SUMMARY

This summary highlights selected information from this joint proxy statement/prospectus. It may not contain all of the information that is important to you. You are urged to read carefully the entire joint proxy statement/prospectus and the other documents attached to or referred to in this joint proxy statement/prospectus in order to fully understand the merger agreement and the proposed merger. See “Where You Can Find More Information” beginning on page 254 of this joint proxy statement/prospectus. Each item in this summary refers to the page of this joint proxy statement/prospectus on which the more detailed discussion of that subject begins.

The Companies (see page 73)

CVS Health Corporation

CVS Health Corporation was incorporated in the State of Delaware on August 22, 1996. CVS Health, together with its subsidiaries, is a pharmacy innovation company helping people on their path to better health. At the forefront of a changing health care landscape, CVS Health has an unmatched suite of capabilities and the expertise needed to drive innovations that will help shape the future of health care.

Through more than 9,700 retail locations, more than 1,100 walk-in health care clinics, a leading pharmacy benefits manager with nearly 90 million plan members, a dedicated senior pharmacy care business serving more than one million patients per year, expanding specialty pharmacy services and a leading stand-alone Medicare Part D prescription drug plan, CVS Health enables people, businesses and communities to manage health in more affordable, effective ways. CVS Health is delivering break-through products and services, from advising patients on their medications at CVS Pharmacy^® locations, to introducing unique programs to help control costs for CVS Health’s clients at CVS Caremark^®, to innovating how care is delivered to CVS Health’s patients with complex conditions through CVS Specialty^®, to improving pharmacy care for the senior community through Omnicare^®, or by expanding access to high-quality, low-cost care at CVS MinuteClinic^®.

The principal trading market for shares of CVS Health common stock (NYSE: CVS) is the NYSE. The principal executive offices of CVS Health are located at One CVS Drive, Woonsocket, RI 02895; its telephone number is (401) 765-1500; and its website is www.cvshealth.com. Information on CVS Health’s Internet website is not incorporated by reference into or otherwise part of this joint proxy statement/prospectus.

This joint proxy statement/prospectus incorporates important business and financial information about CVS Health from other documents that are not included in or delivered with this joint proxy statement/prospectus. For a list of the documents that are incorporated by reference, see “Where You Can Find More Information” beginning on page 254 of this joint proxy statement/prospectus.

Aetna Inc.

Aetna Inc. was incorporated in the Commonwealth of Pennsylvania on December 20, 1982. Aetna, together with its subsidiaries, is one of the nation’s leading diversified health care benefits companies, serving an estimated 37.9 million people as of December 31, 2017. Aetna has the information and resources to help its members, in consultation with their health care professionals, make better informed decisions about their health care. Aetna offers a broad range of traditional, voluntary and consumer-directed health insurance products and related services, including medical, pharmacy, dental, behavioral health, group life and disability plans, medical management capabilities, Medicaid health care management services, Medicare Advantage and Medicare supplement plans, workers’ compensation administrative services and health information technology products and services. Aetna’s customers include employer groups, individuals, college students, part-time and hourly workers, health plans, health care providers, governmental units, government-sponsored plans, labor groups and expatriates. On November 1, 2017, Aetna sold its domestic group life insurance, group disability insurance and absence management businesses to Hartford Life and Accident Insurance Company.

The principal trading market for Aetna common shares (NYSE: AET) is the NYSE. The principal executive offices of Aetna are located at 151 Farmington Avenue, Hartford, CT 06156; its telephone number is (860) 273-0123; and its website is www.aetna.com. Information on Aetna’s Internet website is not incorporated by reference into or otherwise part of this joint proxy statement/prospectus.

This joint proxy statement/prospectus incorporates important business and financial information about Aetna from other documents that are not included in or delivered with this joint proxy statement/prospectus. For a list of the documents that are incorporated by reference, see “Where You Can Find More Information” beginning on page 254 of this joint proxy statement/prospectus.

Hudson Merger Sub Corp.

Merger Sub was incorporated in the Commonwealth of Pennsylvania on November 14, 2017, and is a wholly-owned subsidiary of CVS Health. Merger Sub was formed solely for the purpose of completing the merger. Merger Sub has not carried on any activities to date, except for activities incidental to its formation and activities undertaken in connection with the merger.

The principal executive offices of Merger Sub are located at One CVS Drive, Woonsocket, RI 02895; and its telephone number is (401) 765-1500.

The Merger (see page 177)

CVS Health, Merger Sub and Aetna have entered into the merger agreement. Subject to the terms and conditions of the merger agreement and in accordance with applicable law, in the merger, Merger Sub will be merged with and into Aetna, with Aetna continuing as the surviving corporation and a wholly-owned subsidiary of CVS Health. Upon completion of the merger, Aetna common shares will no longer be publicly traded.

A copy of the merger agreement is attached as Annex A to this joint proxy statement/prospectus. You should read the merger agreement carefully because it is the legal document that governs the merger.

Special Meeting of Stockholders of CVS Health (see page 75)

Meeting. The CVS Health special meeting will be held on March 13, 2018, at the offices of Shearman & Sterling LLP, located at 599 Lexington Avenue, New York, NY 10022, at 11:00 a.m. Eastern Time. At the CVS Health special meeting, CVS Health stockholders will be asked to consider and vote on the following proposals:

Record Date. CVS Health’s board of directors has fixed the close of business on February 5, 2018, as the record date for the determination of the stockholders entitled to notice of and to vote at the CVS Health special meeting or any adjournment or postponement of the CVS Health special meeting. Only CVS Health stockholders of record at the record date are entitled to receive notice of, and to vote at, the CVS Health special meeting or any adjournment or postponement of the CVS Health special meeting. As of the close of business on February 5, 2018, there were 1,015,460,751 shares of CVS Health common stock outstanding and entitled to vote at the CVS Health special meeting. Each holder of shares of CVS Health common stock is entitled to one vote for each share of CVS Health common stock owned at the record date.

Quorum. The presence at the CVS Health special meeting, in person or by proxy, of the holders of a majority of the outstanding shares of CVS Health common stock at the record date (the close of business on

February 5, 2018) will constitute a quorum. Elections to abstain from voting will be deemed present at the CVS Health special meeting for the purpose of determining the presence of a quorum. Shares of CVS Health common stock held in “street name” with respect to which the beneficial owner fails to give voting instructions to the broker, bank or other nominee holder of record, and shares of CVS Health common stock with respect to which the beneficial owner otherwise fails to vote, will not be deemed present at the CVS Health special meeting for the purpose of determining the presence of a quorum. There must be a quorum for the vote on the stock issuance to be taken at the CVS Health special meeting. Failure of a quorum to be present at the CVS Health special meeting will necessitate an adjournment of the meeting and will subject CVS Health to additional expense.

Required Vote. Assuming a quorum is present, approval of the stock issuance requires the affirmative vote of a majority of the votes cast at the CVS Health special meeting by holders of shares of CVS Health common stock. CVS Health cannot complete the merger unless its stockholders approve the stock issuance. Under the current rules and interpretive guidance of the NYSE, “votes cast” on the stock issuance consist of votes “for” or “against”, as well as elections to abstain from voting on the stock issuance. As a result, a CVS Health stockholder’s election to abstain from voting on the stock issuance will have the same effect as a vote “AGAINST” the proposal. Assuming a quorum is present, the failure of a CVS Health stockholder who holds his or her shares in “street name” through a broker, bank or other nominee holder of record to give voting instructions to that broker, bank or other nominee holder of record or any other failure of a CVS Health stockholder to vote will have no effect on the outcome of any vote to approve the stock issuance because these failures to vote are not considered “votes cast.”

Approval of the CVS Health adjournment proposal, whether or not a quorum, as defined under Delaware law, is present, requires the affirmative vote of a majority of the votes cast at the CVS Health special meeting by CVS Health stockholders. For purposes of the CVS Health adjournment proposal, “votes cast” means votes “for” or “against” the proposal. As a result, a CVS Health stockholder’s election to abstain from voting on the CVS Health adjournment proposal, the failure of a CVS Health stockholder who holds his or her shares in “street name” through a broker, bank or other nominee holder of record to give voting instructions to that broker, bank or other nominee holder of record or any other failure of a CVS Health stockholder to vote will have no effect on the outcome of any vote on the CVS Health adjournment proposal.

Stock Ownership of and Voting by CVS Health Directors and Executive Officers. At the record date for the CVS Health special meeting (the close of business on February 5, 2018), CVS Health’s directors and executive officers and their affiliates beneficially owned and had the right to vote in the aggregate 1,279,586 shares of CVS Health common stock at the CVS Health special meeting, which represents approximately 0.13% of the shares of CVS Health common stock entitled to vote at the CVS Health special meeting. Approval of the stock issuance requires the affirmative vote of a majority of the votes cast at the CVS Health special meeting by holders of shares of CVS Health common stock (assuming a quorum is present).

Each of CVS Health’s directors and executive officers is expected, as of the date of this joint proxy statement/prospectus, to vote his or her shares of CVS Health common stock “FOR” the stock issuance and “FOR” the CVS Health adjournment proposal, although none of CVS Health’s directors and executive officers has entered into any agreement requiring them to do so.

Special Meeting of Shareholders of Aetna (see page 82)

Meeting. The Aetna special meeting will be held on March 13, 2018, at the offices of Davis Polk & Wardwell LLP, located at 450 Lexington Avenue, New York, NY 10017, at 11:00 a.m. Eastern Time. At the Aetna special meeting, Aetna shareholders will be asked to consider and vote on the following proposals:

Record Date. A committee of Aetna’s board of directors has fixed the close of business on February 5, 2018, as the record date for the determination of the Aetna shareholders entitled to notice of and to vote at the Aetna special meeting or any adjournment or postponement of the Aetna special meeting. Only Aetna shareholders of record at the record date are entitled to receive notice of, and to vote at, the Aetna special meeting or any adjournment or postponement of the Aetna special meeting. As of the close of business on February 5, 2018, there were 326,942,525 Aetna common shares outstanding and entitled to vote at the Aetna special meeting. Each holder of Aetna common shares is entitled to one vote for each Aetna common share owned at the record date.

Quorum. The presence at the Aetna special meeting, in person or by proxy, of the holders of a majority of the outstanding Aetna common shares at the record date (the close of business on February 5, 2018) will constitute a quorum. Aetna common shares whose holders elect to abstain from voting will be deemed present at the Aetna special meeting for the purpose of determining the presence of a quorum. Aetna common shares held in “street name” with respect to which the beneficial owner fails to give voting instructions to the broker, bank or other nominee holder of record, and Aetna common shares with respect to which the beneficial owner otherwise fails to vote, will not be deemed present at the Aetna special meeting for the purpose of determining the presence of a quorum. There must be a quorum for the vote on the approval and adoption of the merger agreement and the vote on the Aetna compensation advisory proposal to be taken at the Aetna special meeting. Failure of a quorum to be present at the Aetna special meeting will necessitate an adjournment of the meeting and will subject Aetna to additional expense.

Required Vote. Pursuant to Aetna’s amended and restated articles of incorporation, which are referred to in this joint proxy statement/prospectus as Aetna’s articles, to approve and adopt the merger agreement, the affirmative vote of the holders of a majority of Aetna common shares outstanding and entitled to vote thereon is required. Aetna cannot complete the merger and the merger consideration will not be paid unless its shareholders approve and adopt the merger agreement. Because approval and adoption of the merger agreement requires the affirmative vote of the holders of at least a majority of Aetna common shares outstanding and entitled to vote thereon, an Aetna shareholder’s abstention from voting, the failure of an Aetna shareholder who holds his or her shares in “street name” through a broker, bank or other nominee holder of record to give voting instructions to that broker, bank or other nominee holder of record or any other failure of an Aetna shareholder to vote will have the same effect as a vote “AGAINST” the proposal to approve and adopt the merger agreement.

To approve (i) the Aetna adjournment proposal (whether or not a quorum, as defined under Pennsylvania law, is present) and (ii) on an advisory (non-binding) basis, the Aetna compensation advisory proposal (assuming a quorum, as defined under Pennsylvania law, is present), the affirmative vote of a majority of the votes cast at the Aetna special meeting by holders of Aetna common shares is required. For purposes of each of the Aetna adjournment proposal and the Aetna compensation advisory proposal, “votes cast” means votes “for” or “against” the applicable proposal. As a result, an Aetna shareholder’s abstention from voting, the failure of an Aetna shareholder who holds his or her shares in “street name” through a broker, bank or other nominee holder of record to give voting instructions to that broker, bank or other nominee holder of record or any other failure of an Aetna shareholder to vote will have no effect on the outcome of any vote on the Aetna adjournment proposal or any vote to approve, on an advisory (non-binding) basis, the Aetna compensation advisory proposal.

Share Ownership of and Voting by Aetna Directors and Executive Officers. At the record date for the Aetna special meeting (the close of business on February 5, 2018), Aetna’s directors and executive officers and their affiliates beneficially owned and had the right to vote in the aggregate 1,357,761 Aetna common shares at the Aetna special meeting, which represents approximately 0.42% of the Aetna common shares entitled to vote at the Aetna special meeting. To approve and adopt the merger agreement, the affirmative vote of the holders of a majority of Aetna common shares outstanding and entitled to vote thereon is required.

Each of Aetna’s directors and executive officers is expected, as of the date of this joint proxy statement/prospectus, to vote his or her Aetna common shares “FOR” the proposal to approve and adopt the merger agreement, “FOR” the Aetna adjournment proposal and “FOR” the Aetna compensation advisory proposal, although none of Aetna’s directors or executive officers has entered into any agreement requiring them to do so.

What Aetna Shareholders Will Receive in the Merger (see page 178)

If the merger is completed, Aetna shareholders will be entitled to receive, in exchange for each Aetna common share that they own immediately prior to the effective time of the merger, $145.00 in cash without interest thereon and 0.8378 of a share of CVS Health common stock, together with cash payable in lieu of any fractional shares as described below.

CVS Health will not issue any fractional shares in the merger. Instead, the total number of shares of CVS Health common stock that each Aetna shareholder will be entitled to receive in the merger will be rounded down to the nearest whole number, and each Aetna shareholder will be entitled to receive cash, without interest thereon, for any fractional share of CVS Health common stock that he or she otherwise would be entitled to receive in the merger. The amount of cash for fractional shares will be calculated by multiplying the fraction of a share of CVS Health common stock that the Aetna shareholder otherwise would be entitled to receive in the merger by the CVS Health closing price.

Example: If you own 100 Aetna common shares at the time the merger is completed, you will be entitled to receive $14,500.00 in cash without interest thereon and 83 shares of CVS Health common stock. In addition, you will be entitled to receive an amount of cash equal to 0.78 of a share of CVS Health common stock multiplied by the CVS Health closing price.

The exchange ratio is fixed, which means that it will not change between now and the date of the merger, regardless of whether the market price of either shares of CVS Health common stock or Aetna common shares changes. Therefore, the value of the share consideration will depend on the market price of shares of CVS Health common stock at the time Aetna shareholders receive shares of CVS Health common stock in the merger. Based on the closing price of a share of CVS Health common stock on the NYSE on October 25, 2017, the last trading day prior to news reports of a potential transaction between CVS Health and Aetna, the merger consideration represented approximately $208.28 in value for each Aetna common share. Based on the closing price of a share of CVS Health common stock on the NYSE on February 8, 2018, the most recent trading day prior to the date of this joint proxy statement/prospectus for which this information was available, the merger consideration represented approximately $204.11 in value for each Aetna common share. The market price of shares of CVS Health common stock has fluctuated since the date of the announcement of the merger agreement and will continue to fluctuate from the date of this joint proxy statement/prospectus to the date of the Aetna special meeting and the date the merger is completed and thereafter. The market price of shares of CVS Health common stock when received by Aetna shareholders after the merger is completed could be greater than, less than or the same as the market price of shares of CVS Health common stock on the date of this joint proxy statement/prospectus or at the time of the Aetna special meeting or any adjournment or postponement thereof.

Treatment of Aetna Equity Awards (see page 180)

At completion of the merger, each outstanding vested Aetna stock appreciation right (including those Aetna stock appreciation rights that vest by their terms at completion of the merger), will be cancelled and converted into the right to receive an amount in cash, without interest, equal to the excess, if any, of the equity award cash consideration over the applicable per share exercise price of such Aetna stock appreciation right multiplied by the total number of Aetna common shares subject to such Aetna stock appreciation right.

Each Aetna stock appreciation right that is not vested as of completion of the merger or that is granted after the date of the merger agreement (to the extent permitted under the merger agreement), at completion of the merger, will be assumed by CVS Health and will become an assumed stock appreciation right representing the right to receive a payment in shares of CVS Health common stock on the same terms and conditions, except that the number of shares of CVS Health common stock subject to the assumed stock appreciation right will equal the product of the number of Aetna common shares that were subject to such Aetna stock appreciation right immediately prior to completion of the merger multiplied by the equity award exchange ratio, with such product rounded down to the nearest whole share of CVS Health common stock. The per share exercise price for each assumed stock appreciation right will equal the exercise price per share of such Aetna stock appreciation right immediately prior to completion of the merger divided by the equity award exchange ratio, rounded up to the nearest whole cent.

Immediately prior to completion of the merger, each outstanding Aetna RSU and each outstanding Aetna PSU that provides for accelerated vesting upon completion of the merger will vest and will be converted into the right to receive, with respect to each Aetna common share underlying the Aetna RSU or Aetna PSU, the merger consideration, less applicable tax withholdings.

Each Aetna RSU or Aetna PSU that is not converted into a right to receive the merger consideration or is granted after the date of the merger agreement (to the extent permitted under the merger agreement) will be assumed by CVS Health and will be converted into a time-based restricted stock unit award covering the number of whole shares of CVS Health common stock equal to the product of the number of Aetna common shares underlying such assumed Aetna RSU or Aetna PSU immediately prior to completion of the merger (with the performance of each Aetna PSU to be determined based on the applicable award agreement relating to such Aetna PSU) multiplied by the equity award exchange ratio, with such product rounded down to the nearest whole share of CVS Health common stock. Except as provided in the immediately preceding sentence, each assumed Aetna RSU or Aetna PSU will continue to have, and be subject to, the same terms and conditions as applied to the corresponding Aetna RSU or Aetna PSU immediately prior to completion of the merger (including any terms and conditions relating to accelerated vesting upon a termination of the holder’s employment in connection with or following the merger).

The description above does not apply to equity awards held by Aetna’s non-employee directors, who will receive a cash payment for their restricted and deferred units in accordance with the Aetna Director Plan.

Recommendations of the Aetna Board of Directors (see page 101)

Aetna’s board of directors unanimously determined that the merger agreement and the transactions contemplated by the merger agreement (including the merger) are fair to and in the best interests of Aetna and its shareholders. Aetna’s board of directors unanimously recommends that Aetna shareholders vote “FOR” the proposal to approve and adopt the merger agreement. For the factors considered by Aetna’s board of directors in reaching this decision, see “Aetna Proposal I: Approval and Adoption of the Merger Agreement and CVS Health Proposal I: Approval of the Stock Issuance—Aetna’s Reasons for the Merger; Recommendation of the Aetna Board of Directors that Aetna Shareholders Approve and Adopt the Merger Agreement” beginning on page 101 of this joint proxy statement/prospectus.

Aetna’s board of directors unanimously recommends that Aetna shareholders vote “FOR” the Aetna adjournment proposal. See “Aetna Proposal II: Adjournment of the Aetna Special Meeting” beginning on page 219 of this joint proxy statement/prospectus.

In addition, Aetna’s board of directors unanimously recommends that Aetna shareholders vote “FOR” the Aetna compensation advisory proposal. See “Aetna Proposal III: Advisory Vote On Merger-Related Executive Compensation Arrangements” beginning on page 220 of this joint proxy statement/prospectus.

Recommendations of the CVS Health Board of Directors (see page 107)

CVS Health’s board of directors unanimously determined that the merger agreement and the transactions contemplated by the merger agreement, including merger and the stock issuance, are advisable, fair to and in the best interests of CVS Health and its stockholders. CVS Health’s board of directors unanimously recommends that CVS Health stockholders vote “FOR” the stock issuance. For the factors considered by CVS Health’s board of directors in reaching this decision, see “Aetna Proposal I: Approval and Adoption of the Merger Agreement and CVS Health Proposal I: Approval of the Stock Issuance—CVS Health’s Reasons for the Merger; Recommendation of the CVS Health Board of Directors that CVS Health Stockholders Approve the Stock Issuance” beginning on page 107 of this joint proxy statement/prospectus.

CVS Health’s board of directors unanimously recommends that CVS Health stockholders vote “FOR” the CVS Health adjournment proposal. See “CVS Health Proposal II: Adjournment of the CVS Health Special Meeting” beginning on page 221 of this joint proxy statement/prospectus.

Opinions of Aetna’s Financial Advisors (see page 111)

Opinion of Lazard Frères & Co. LLC

Aetna has engaged Lazard Frères & Co. LLC, which is referred to in this joint proxy statement/prospectus as Lazard, as a financial advisor in connection with the merger. In connection with the merger, Lazard delivered a written opinion, dated December 3, 2017, to the Aetna board of directors as to the fairness, from a financial point of view and as of such date, of the consideration to be paid to the holders of Aetna common shares in the merger.

The full text of Lazard’s written opinion, dated December 3, 2017, which sets forth the assumptions made, procedures followed, matters considered and qualifications and limitations on the review undertaken, is attached as Annex B to this joint proxy statement/prospectus and is incorporated herein by reference. The description of Lazard’s opinion set forth in this joint proxy statement/prospectus is qualified in its entirety by reference to the full text of Lazard’s opinion. Lazard’s opinion was for the benefit of the Aetna board of directors (in its capacity as such) in connection with its evaluation of the merger and did not address any terms or other aspects (other than the merger consideration to the extent expressly specified in Lazard’s opinion) of the merger. Lazard’s opinion did not address the relative merits of the merger as compared to any other transaction or business strategy in which Aetna might engage or the merits of the underlying decision by Aetna to engage in the merger. Lazard’s opinion is not intended to and does not constitute a recommendation to any shareholder as to how such shareholder should vote or act with respect to the merger or any matter relating thereto.

Opinion of Allen & Company LLC

Aetna also has engaged Allen & Company LLC, which is referred to in this joint proxy statement/prospectus as Allen & Company, as a financial advisor in connection with the merger. In connection with the merger, Allen & Company delivered a written opinion, dated December 3, 2017, to the Aetna board of directors as to the fairness, from a financial point of view and as of the date of the opinion, of the consideration to be received by holders of Aetna common shares pursuant to the merger agreement.

The full text of Allen & Company’s written opinion, dated December 3, 2017, which describes the assumptions made, procedures followed, matters considered and qualifications and limitations on the review undertaken, is attached as Annex C to this joint proxy statement/prospectus and is incorporated herein by reference. The description of Allen & Company’s opinion set forth in this joint proxy statement/prospectus is qualified in its entirety by reference to the full text of Allen & Company’s opinion. Allen & Company’s opinion was intended for the benefit and use of the Aetna board of directors (in its capacity as such) in connection

with its evaluation of the merger consideration from a financial point of view and did not address any other terms, aspects or implications of the merger. Allen & Company’s opinion did not constitute a recommendation as to the course of action that Aetna (or the Aetna board of directors) should pursue in connection with the merger or otherwise address the merits of the underlying decision by Aetna to engage in the merger, including in comparison to other strategies or transactions that might be available to Aetna or which Aetna might engage in or consider. Allen & Company’s opinion does not constitute advice or a recommendation to any shareholder as to how such shareholder should vote or act on any matter relating to the merger or otherwise.

Opinions of CVS Health’s Financial Advisors (see page 128)

Opinions of Barclays Capital Inc. and Goldman Sachs & Co. LLC

CVS Health engaged Barclays Capital Inc., which is referred to in this joint proxy statement/prospectus as Barclays, and Goldman Sachs & Co. LLC, which is referred to in this joint proxy statement/prospectus as Goldman Sachs, to act as its financial advisors with respect to the merger. Barclays delivered its opinion to CVS Health’s board of directors that, as of December 3, 2017 and based upon and subject to the qualifications, limitations, factors and assumptions set forth in the opinion, the merger consideration to be paid by CVS Health in the merger was fair, from a financial point of view, to CVS Health. Goldman Sachs delivered its opinion to CVS Health’s board of directors that, as of December 3, 2017 and based upon and subject to the qualifications, limitations, factors and assumptions set forth in the opinion, the merger consideration to be paid by CVS Health in the merger was fair, from a financial point of view, to CVS Health.

The full text of the written opinion of Barclays, dated as of December 3, 2017, is attached as Annex D to this joint proxy statement/prospectus. Barclays’ written opinion sets forth, among other things, the assumptions made, procedures followed, factors considered and limitations on the review undertaken by Barclays in connection with the opinion. Barclays provided advisory services and its opinion for the information and assistance of CVS Health’s board of directors in connection with its consideration of the merger. The Barclays opinion is not a recommendation as to how any holder of shares of CVS Health common stock or Aetna common shares should vote with respect to the merger or any other matter.

The full text of the written opinion of Goldman Sachs, dated as of December 3, 2017, is attached as Annex E to this joint proxy statement/prospectus. Goldman Sachs’ written opinion sets forth, among other things, the assumptions made, procedures followed, factors considered and limitations on the review undertaken by Goldman Sachs in connection with the opinion. Goldman Sachs provided advisory services and its opinion for the information and assistance of CVS Health’s board of directors in connection with its consideration of the merger. The Goldman Sachs opinion is not a recommendation as to how any holder of shares of CVS Health common stock or Aetna common shares should vote with respect to the merger or any other matter.

Opinion of Centerview Partners LLC

CVS Health also retained Centerview Partners LLC, which is referred to in this joint proxy statement/prospectus as Centerview, as financial advisor to CVS Health in connection with the proposed merger and the other transactions contemplated by the merger agreement, which are collectively referred to as the transaction throughout this section and the summary of Centerview’s opinion below under the caption “Opinions of CVS Health’s Financial Advisors—Opinion of Centerview Partners LLC” beginning on page 145 of this joint proxy statement/prospectus. In connection with this engagement, the board of directors of CVS Health requested that Centerview evaluate the fairness, from a financial point of view, to CVS Health, of the merger consideration to be paid by CVS Health in the merger pursuant to the merger agreement. On December 3, 2017, Centerview

rendered to the board of directors of CVS Health its oral opinion, which was subsequently confirmed by delivery of a written opinion dated December 3, 2017 that, as of such date and based upon and subject to the assumptions made, procedures followed, matters considered, and qualifications and limitations upon the review undertaken by Centerview in preparing its opinion, the merger consideration proposed to be paid by CVS Health in the merger pursuant to the merger agreement was fair, from a financial point of view, to CVS Health.

The full text of Centerview’s written opinion, dated December 3, 2017, which describes the assumptions made, procedures followed, matters considered, and qualifications and limitations upon the review undertaken by Centerview in preparing its opinion, is attached as Annex F and is incorporated herein by reference. Centerview’s financial advisory services and opinion were provided for the information and assistance of the board of directors of CVS (in their capacity as directors and not in any other capacity) in connection with and for purposes of its consideration of the transaction and Centerview’s opinion addressed only the fairness, from a financial point of view, as of the date of Centerview’s written opinion, to CVS of the merger consideration to be paid by CVS in the merger pursuant to the merger agreement. Centerview’s opinion did not address any other term or aspect of the merger agreement or the transaction and does not constitute a recommendation to any stockholder of CVS or any other person as to how such stockholder or other person should vote with respect to the merger or otherwise act with respect to the transaction or any other matter.

The full text of Centerview’s written opinion should be read carefully in its entirety for a description of the assumptions made, procedures followed, matters considered, and qualifications and limitations upon the review undertaken by Centerview in preparing its opinion.

Ownership of CVS Health Common Stock After the Merger (see page 89)

Based on the number of Aetna common shares (including the number of shares underlying Aetna stock appreciation rights, Aetna RSUs, Aetna PSUs and unexercised rights under the Aetna employee stock purchase plan) outstanding as of February 5, 2018, and the treatment of Aetna common shares, stock appreciation rights, Aetna RSUs, Aetna PSUs and unexercised rights under the Aetna employee stock purchase plan in the merger, CVS Health expects to issue approximately 280 million shares of CVS Health common stock to Aetna shareholders and Aetna equity award holders upon completion of the merger and reserve for issuance additional shares of CVS Health common stock in connection with the assumption, exercise and settlement of Aetna stock appreciation rights, Aetna RSUs and Aetna PSUs that are not vested as of completion of the merger or that are granted after the date of the merger agreement (to the extent permitted by the merger agreement). The actual number of shares of CVS Health common stock to be issued and reserved for issuance upon completion of the merger will be determined at completion of the merger based on the exchange ratio and the number of Aetna common shares (including the number of shares underlying Aetna stock appreciation rights, Aetna RSUs, Aetna PSUs and unexercised rights under the Aetna employee stock purchase plan) outstanding at that time. Based on the number of Aetna common shares (including the number of shares underlying Aetna stock appreciation rights, Aetna RSUs, Aetna PSUs and unexercised rights under the Aetna employee stock purchase plan) outstanding as of February 5, 2018, and the number of shares of CVS Health common stock outstanding as of February 5, 2018, it is expected that, immediately after completion of the merger, former Aetna shareholders will own approximately 22% of the outstanding shares of CVS Health common stock.

Governance and Social Matters Following Completion of the Merger (see page 180)

At completion of the merger, the size of the board of directors of CVS Health will be increased by three and the vacancies created thereby will be filled by Mark T. Bertolini, the Chairman and Chief Executive Officer of Aetna, and two other individuals who are serving on the board of directors of Aetna immediately prior to completion of the merger who meet CVS Health’s independence criteria as in effect as of such time and who will

be jointly designated by Aetna and CVS Health prior to completion of the merger. See “The Merger Agreement—Governance and Social Matters Following Completion of the Merger” beginning on page 180 for further information.

The merger agreement provides that, for at least three years following completion of the merger, CVS Health will preserve Aetna Foundation, Inc. in a manner consistent in all material respects with the past practice of Aetna, including by maintaining its name and its charitable mission.

The merger agreement also provides that, for at least five years following completion of the merger, CVS Health will maintain “Aetna” as the primary brand for the insurance businesses of CVS Health and its subsidiaries (including Aetna and its subsidiaries).

Interests of Aetna’s Directors and Executive Officers in the Merger (see page 209)

In considering the recommendation of the Aetna board of directors to approve and adopt the merger agreement, Aetna shareholders should be aware that Aetna’s directors and executive officers have interests in the merger that may be different from, or in addition to, the interests of Aetna shareholders generally. Aetna’s board of directors was aware of these interests and considered them, among other matters, in evaluating and negotiating the merger agreement, in reaching its decision to approve the merger agreement and the transactions contemplated by the merger agreement (including the merger), and in recommending to Aetna shareholders that the merger agreement be approved and adopted.

These interests include the following:

These interests are described in further detail, including more information on the assumptions used in calculating the estimated amounts set forth above, under “Interests of Aetna’s Directors and Executive Officers in the Merger” and “The Merger Agreement—Indemnification and Insurance” beginning on pages 209 and 201, respectively, of this joint proxy statement/prospectus.

Listing of CVS Health Common Stock; Delisting and Deregistration of Aetna Common Shares (see page 170)

CVS Health will apply to have the shares of CVS Health common stock to be issued in the merger approved for listing on the NYSE, where shares of CVS Health common stock are currently traded. If the merger is completed, Aetna common shares will no longer be listed on the NYSE and will be deregistered under the Securities Exchange Act of 1934, as amended, which is referred to in this joint proxy statement/prospectus as the Exchange Act.

Appraisal or Dissenters’ Rights Not Available to Aetna Shareholders (see page 167)

Under Pennsylvania law, Aetna shareholders will not be entitled to appraisal or dissenters’ rights in connection with the merger.

Completion of the Merger Is Subject to Certain Conditions (see page 181)

As more fully described in this joint proxy statement/prospectus and in the merger agreement, the obligation of each of CVS Health and Merger Sub, on the one hand, and Aetna, on the other hand, to complete the merger is subject to the satisfaction (or, to the extent permitted by applicable law, waiver) of a number of conditions, including the following:

In addition to the conditions to all parties’ obligations, the obligations of CVS Health and Merger Sub to complete the merger are subject to the satisfaction (or, to the extent permitted by applicable law, waiver) of certain additional conditions, including the following:

In addition to the conditions to all parties’ obligations, the obligation of Aetna to complete the merger is subject to the satisfaction (or, to the extent permitted by applicable law, waiver) of certain additional conditions, including (i) expiration or early termination of the waiting period relating to the merger under the HSR Act and (ii) the required governmental authorizations having been made or obtained.

CVS Health and Aetna cannot be certain when, or if, the conditions to the merger will be satisfied or waived, or that the merger will be completed.

The Merger May Not Be Completed Without All Required Regulatory Approvals (see page 165)

Completion of the merger is conditioned upon the expiration or early termination of the waiting period relating to the merger under the HSR Act and the required governmental authorizations having been made or obtained and being in full force and effect, and in the case of CVS Health, without the imposition of any term or condition that would have or would reasonably be expected to have, individually or in the aggregate, a regulatory material adverse effect on CVS Health or Aetna.

Under the HSR Act, certain transactions, including the merger, may not be completed unless certain waiting period requirements have expired or been terminated. The HSR Act provides that each party must file a pre-merger notification with the Federal Trade Commission, which is referred to in this joint proxy statement/prospectus as the FTC, and the Antitrust Division of the U.S. Department of Justice, which is referred to in this joint proxy statement/prospectus as the DOJ. A transaction notifiable under the HSR Act may not be completed until the expiration of a 30-calendar-day waiting period following the parties’ filings of their respective HSR Act notification forms or the early termination of that waiting period. The merger is being reviewed by the DOJ. If the DOJ issues a Request for Additional Information and Documentary Material prior to the expiration of the initial waiting period, the parties must observe a second 30-calendar-day waiting period, which would begin to run only after both parties have substantially complied with the request for additional information, unless the waiting period is terminated earlier.

Each of CVS Health and Aetna filed its respective HSR Act notification and report with respect to the merger on January 2, 2018. On February 1, 2018, CVS Health and Aetna each received a request for additional information, which is referred to in this joint proxy statement/prospectus as the second request, from the DOJ in connection with the DOJ’s review of the transactions contemplated by the merger agreement. Issuance of the second request extends the waiting period under the HSR Act until 30 days after both CVS Health and Aetna

have substantially complied with the second request or such later time as the parties may agree with the DOJ, unless the waiting period is terminated earlier by the DOJ. CVS Health and Aetna have been cooperating with the DOJ staff since shortly after the announcement of the merger agreement and are continuing to cooperate with the DOJ staff in its review of the transactions contemplated by the merger agreement.

Pursuant to federal health care laws and regulations and, in some instances, the health care and insurance laws and regulations of certain states, and pursuant to certain licenses and contracts of certain of Aetna’s subsidiaries, applicable federal and state regulatory and governmental authorities must approve, or be notified of, CVS Health’s acquisition of control of Aetna’s health maintenance organizations, insurance companies, pharmacy businesses and other regulated businesses or entities. To obtain these approvals and provide such notices, CVS Health, or the applicable CVS Health subsidiary, and in some instances Aetna, or the applicable Aetna regulated entity, as the case may be, has filed and/or will file acquisition of control and/or material modification or other statements, notices or applications, as required by federal health care law or regulation and the insurance and health care laws and regulations of each applicable state and country or the Aetna regulated entities’ licenses and contracts. In addition, certain non-U.S. governmental authorities must approve, or be notified of, the merger, and CVS Health and/or Aetna and/or their respective subsidiaries will file all such statements, notices, or applications, as are required by the laws of applicable non-U.S. governmental authorities.

Neither CVS Health nor Aetna is aware of any material governmental approvals or actions that are required for completion of the merger other than those described above. It is presently contemplated that if any such additional material governmental approvals or actions are required, those approvals or actions will be sought.

CVS Health and Aetna have agreed to use their respective reasonable best efforts to obtain all regulatory approvals required to complete the merger, which reasonable best efforts include contesting any proceeding brought by a governmental authority seeking to prohibit completion of the merger or seeking damages or to impose any terms or conditions in connection with the merger. In using its reasonable best efforts, under the terms of the merger agreement, CVS Health is required to take all actions and do all things necessary, proper or advisable to complete the merger in connection with (i) the expiration or early termination of the waiting period relating to the merger under the HSR Act, (ii) any other antitrust law or (iii) the required governmental authorizations, except that CVS Health is not required to take any action or agree to any term or condition in connection with those matters if that action, term or condition would have or would reasonably be expected to have, individually or in the aggregate, a regulatory material adverse effect on CVS Health or on Aetna (see “The Merger Agreement—Reasonable Best Efforts Covenant” beginning on page 194 of this joint proxy statement/prospectus for the definition of regulatory material adverse effect). In addition, in connection with obtaining the regulatory approvals required to complete the merger, (x) neither CVS Health nor Aetna is required to take any action or agree to any term or condition that is not conditioned upon completion of the merger and (y) Aetna is not permitted to take any action or agree to any term or condition without CVS Health’s consent.

Description of Debt Financing (see page 170)

The merger is not subject to a financing condition. On December 3, 2017, CVS Health entered into a bridge facility commitment letter, which is referred to in this joint proxy statement/prospectus as the bridge facility commitment letter, with Barclays Bank PLC, Goldman Sachs Bank USA, Goldman Sachs Lending Partners LLC, Bank of America, N.A. and Merrill Lynch, Pierce, Fenner & Smith Incorporated (solely in its capacity as an arranger), to finance up to $49.0 billion of the cash consideration and fees, commissions and expenses payable by CVS Health in connection with the merger to the extent that CVS Health has not received $49.0 billion of net cash proceeds from a combination of (a) the issuance by CVS Health or one of its wholly-owned subsidiaries of a combination of equity securities, equity-linked securities or unsecured debt securities and/or (b) unsecured term loans, in each case, at or prior to completion of the merger, which is referred to in this joint proxy statement/prospectus as the bridge facility. Barclays Bank PLC, Goldman Sachs Bank USA, Goldman Sachs Lending Partners LLC and Bank of America, N.A. each provided a commitment to fund loans under the bridge facility

and are collectively referred to in this joint proxy statement/prospectus as the initial bridge commitment parties. On December 15, 2017, CVS Health, the initial bridge commitment parties and Merrill Lynch, Pierce, Fenner & Smith Incorporated entered into a joinder agreement to the bridge facility commitment letter, which is referred to in this joint proxy statement/prospectus as the bridge joinder agreement, with JPMorgan Chase Bank, N.A., Wells Fargo Bank, N.A., The Bank of New York Mellon, The Bank of Tokyo-Mitsubishi UFJ, Ltd., Mizuho Bank, Ltd., Royal Bank of Canada, SunTrust Bank, U.S. Bank National Association, Fifth Third Bank, KeyBank National Association, PNC Bank, National Association, Banco Santander, S.A., New York Branch, Sumitomo Mitsui Banking Corporation, Bank of China, New York Branch, Industrial and Commercial Bank of China Limited, New York Branch, The Toronto-Dominion Bank, New York Branch and Guggenheim Life and Annuity Company which are collectively referred to in this joint proxy statement/prospectus as the additional bridge commitment parties. The bridge joinder agreement amends the bridge facility commitment letter and reallocates the commitments of the initial bridge commitment parties to fund loans under the bridge facility among the initial bridge commitment parties and the additional bridge commitment parties. The initial bridge commitment parties together with the additional bridge commitment parties are collectively referred to in this joint proxy statement/prospectus as the bridge commitment parties. The bridge commitment parties’ obligation to fund the bridge facility is subject to several limited conditions as set forth in the bridge facility commitment letter, including, among others, completion of the merger, the non-occurrence of a material adverse effect (as defined in the bridge facility commitment letter) on Aetna, the accuracy in all material respects of certain representations and warranties related to both CVS Health and Aetna, the absence of certain defaults by CVS Health, the delivery of certain financial statements of CVS Health and Aetna and other customary conditions to completion.

On December 15, 2017, CVS Health entered into a term loan agreement, which is referred to in this joint proxy statement/prospectus as the term loan agreement, with a group of twenty banks and other financial institutions, which are collectively referred to in this joint proxy statement/prospectus as the term lenders, consisting of a $3.0 billion three-year tranche and a $2.0 billion five-year tranche, to finance $5.0 billion of the cash consideration and fees, commissions and expenses payable by CVS Health in connection with the merger, which is referred to in this joint proxy statement/prospectus as the term loan facility. The occurrence of the effective date under the term loan agreement on December 15, 2017 had the effect of reducing the bridge facility by a principal amount of $5.0 billion to $44.0 billion. The term lenders’ obligation to fund the term loan facility is subject to several limited conditions as set forth in the term loan agreement, including, among others, completion of the merger, the non-occurrence of a material adverse effect (as defined in the term loan agreement) on Aetna, the accuracy in all material respects of certain representations and warranties related to both CVS Health and Aetna, the absence of certain defaults by CVS Health, the delivery of certain financial statements of CVS Health and Aetna and other customary conditions to completion.

On December 15, 2017, CVS Health and its current group of lenders entered into a first amendment to each of CVS Health’s existing revolving credit facilities (consisting of (i) a $1.0 billion, 364-day unsecured credit facility expiring on May 17, 2018, (ii) a $1.25 billion, five-year unsecured back-up credit facility expiring on July 24, 2019, (iii) a $1.25 billion, five-year unsecured back-up credit facility expiring on July 1, 2020 and (iv) a $1.0 billion, five-year unsecured back-up credit facility expiring on May 18, 2022, which is referred to in this joint proxy statement/prospectus as the 2017 five-year revolving credit facility, to (w) amend the covenant restricting the incurrence of debt by CVS Health’s subsidiaries to up to 15% of net tangible assets, which is referred to in this joint proxy statement/prospectus as the net tangible assets test, by (a) excluding any indebtedness of Aetna and its subsidiaries existing as of completion of the merger (other than any increase, refinancing or replacement thereof), which is referred to in this joint proxy statement/prospectus as the Aetna existing indebtedness, from indebtedness for purposes of determining compliance with the net tangible assets test, and (b) restricting the indebtedness that may be incurred by all of CVS Health’s subsidiaries (excluding the Aetna existing indebtedness and other indebtedness under capital leases incurred in connection with a sale and leaseback transaction) to an amount not exceeding $900.0 million in the aggregate, in each case, on and following completion of the merger until the date that CVS Health is in compliance with the net tangible assets

test without giving effect to the exclusion set forth in clause (a) above, (x) expressly permit completion of the merger under the acquisition covenant, (y) amend the financial covenant by (a) increasing the consolidated indebtedness to total capitalization ratio from 0.60:1.00 to 0.65:1.00 from completion of the merger through and including the fiscal quarter ending September 30, 2019, and (b) excluding unsecured indebtedness in an aggregate principal amount not exceeding $49.0 billion incurred by CVS Health for the purpose of financing the merger (including all of the transaction costs, fees, commissions and expenses in connection therewith) and which is redeemable or prepayable if the merger is not consummated, from the calculation of consolidated indebtedness and total capitalization, until the earliest of the occurrence of completion of the merger, the date that is 30 days following the termination of the merger agreement in accordance with its terms and August 31, 2019, and (z) increase the threshold amount of specified events of default to (a) prior to the later of (i) the termination or other expiration of the bridge facility commitment letter in accordance with its terms and (ii) the termination or other expiration of the bridge facility if it is entered into, $250.0 million, and (b) at all other times, $200.0 million. In this joint proxy statement/prospectus, CVS Health’s existing revolving credit agreements are referred to as the revolving credit agreements, and the lenders under the revolving credit agreements are referred to as the revolving lenders.

For a more complete description of CVS Health’s debt financing for the merger, see “Aetna Proposal I: Approval and Adoption of the Merger Agreement and CVS Health Proposal I: Approval of the Stock Issuance—Description of Debt Financing” beginning on page 170 of this joint proxy statement/prospectus.

CVS Health and Aetna Expect the Merger to be Completed in the Second Half of 2018 (see page 177)

The merger will occur three business days after the conditions to its completion have been satisfied or, to the extent permitted by applicable law, waived, unless otherwise mutually agreed by the parties. As of the date of this joint proxy statement/prospectus, CVS Health and Aetna expect the merger to be completed in the second half of 2018. However, there can be no assurance as to when, or if, the merger will occur.

No Solicitation by Aetna or CVS Health (see page 190)

As more fully described in this joint proxy statement/prospectus and in the merger agreement, and subject to the exceptions described below and in the merger agreement, each of Aetna and CVS Health has agreed not to, among other things, (i) solicit, initiate or take any action to knowingly facilitate or knowingly encourage the submission of any acquisition proposal from any third party, (ii) enter into or participate in any discussions or negotiations with any third party that such party knows is seeking to make, or has made, an acquisition proposal, (iii) fail to make or withdraw or qualify, amend or modify in any manner adverse to the other party the recommendation of such party’s board of directors that its shareholders approve and adopt the merger agreement, in the case of Aetna, or its stockholders approve the stock issuance, in the case of CVS Health, or (iv) fail to enforce or grant any waiver or release under any standstill or similar agreement.

However, at any time prior to the approval and adoption of the merger agreement by Aetna shareholders, in the case of Aetna, or the approval of the stock issuance by CVS Health stockholders, in the case of CVS Health, subject to the terms and conditions described in the merger agreement, each of Aetna or CVS Health, as applicable, is permitted to:

Aetna or CVS Health, as applicable, is only permitted to take the actions described above if its board of directors determines that the failure to take that action would be reasonably likely to be inconsistent with its fiduciary duties under applicable law. In addition, Aetna’s board of directors is not permitted to withdraw or modify its recommendation that Aetna shareholders approve and adopt the merger agreement or to terminate the merger agreement in order to enter into a definitive agreement with respect to a superior proposal, and CVS Health’s board of directors is not permitted to withdraw or modify its recommendation that CVS Health stockholders approve the stock issuance or to terminate the merger agreement in order to enter into a definitive agreement with respect to a superior proposal, unless, before taking that action, the applicable party notifies the other party that it intends to take that action and, if requested by the other party, negotiates in good faith with the other party for certain periods of time regarding any proposal by the other party to amend the terms of the merger agreement.

Termination of the Merger Agreement (see page 203)

As more fully described in this joint proxy statement/prospectus and in the merger agreement, and subject to the terms and conditions set forth in the merger agreement, the merger agreement may be terminated at any time before completion of the merger in any of the following ways:

Termination Fees (see page 205)

As more fully described in this joint proxy statement/prospectus and in the merger agreement, and subject to the terms and conditions of the merger agreement, Aetna has agreed to pay CVS Health a termination fee of $2.1 billion if the merger agreement is terminated under any of the following circumstances:

As more fully described in this joint proxy statement/prospectus and in the merger agreement, and subject to the terms and conditions of the merger agreement, CVS Health has agreed to pay Aetna a termination fee of $2.1 billion if the merger agreement is terminated under any of the following circumstances:

In addition, as more fully described in this joint proxy statement/prospectus and in the merger agreement, and subject to the terms and conditions of the merger agreement, CVS Health has agreed to pay Aetna a termination fee of $2.1 billion if both (x) the merger agreement is terminated under any the following circumstances:

and (y) at the time of termination of the merger agreement, all of the conditions to CVS Health’s and Merger Sub’s obligations to complete the merger are satisfied or waived other than (i) the regulatory approvals condition and (ii) the condition requiring the absence of any applicable law or order being in effect in the U.S. that prohibits completion of the merger (but only if that condition is not satisfied solely due to any applicable law or final and non-appealable order in respect of certain regulatory matters).

Except in the case of fraud, if either party receives a termination fee in accordance with the provisions of the merger agreement, the receipt of the termination fee will be the receiving party’s sole and exclusive remedy against the paying party.

See “The Merger Agreement—Termination Fee and Expenses” beginning on page 205 of this joint proxy statement/prospectus for a more complete description of the circumstances under which Aetna or CVS Health will be required to pay a termination fee.

Specific Performance; Remedies (see page 207)

Under the merger agreement, each of CVS Health and Aetna is entitled to an injunction or injunctions to prevent breaches of the merger agreement and to specifically enforce the terms and provisions of the merger agreement.

Material U.S. Federal Income Tax Consequences (see page 167)

The exchange of Aetna common shares for the merger consideration pursuant to the merger will be a taxable transaction for U.S. federal income tax purposes. Accordingly, an Aetna shareholder that is a U.S. holder (as defined in “Aetna Proposal I: Approval and Adoption of the Merger Agreement and CVS Health Proposal I: Approval of the Stock Issuance—Material U.S. Federal Income Tax Consequences”) will recognize taxable capital gain or loss in an amount equal to the difference, if any, between (i) the sum of (x) the amount of cash, including cash in lieu of fractional shares, received by such U.S. holder in the merger and (y) the fair market value of the shares of CVS Health common stock received by such U.S. holder in the merger and (ii) such U.S. holder’s adjusted tax basis in the Aetna common shares exchanged therefor. With respect to an Aetna shareholder that is a non-U.S. holder (as defined in “Aetna Proposal I: Approval and Adoption of the Merger Agreement and CVS Health Proposal I: Approval of the Stock Issuance—Material U.S. Federal Income Tax Consequences”), the exchange of Aetna common shares for the merger consideration pursuant to the merger generally will not result in tax to such non-U.S. holder under U.S. federal income tax laws unless such non-U.S. holder has certain connections with the United States.

Each Aetna shareholder is urged to read the discussion in the section entitled “Aetna Proposal I: Approval and Adoption of the Merger Agreement and CVS Health Proposal I: Approval of the Stock Issuance—Material U.S. Federal Income Tax Consequences” beginning on page 167 of this joint proxy statement/prospectus and to consult its tax advisor to determine the particular U.S. federal, state or local or non-U.S. income or other tax consequences to it of the merger.

Accounting Treatment (see page 169)

The merger will be accounted for as an acquisition of a business. CVS Health will record assets acquired and liabilities assumed from Aetna primarily at their respective fair values at the date of completion of the merger. Any excess of the purchase price (as described under Note 4. Estimate of Consideration Expected to be Transferred under “CVS Health and Aetna Unaudited Pro Forma Condensed Combined Financial Statements” beginning on page 42 of this joint proxy statement/prospectus) over the net fair value of such assets and liabilities will be recorded as goodwill.

Rights of Aetna Shareholders Will Change as a Result of the Merger (see page 225)

Aetna shareholders will have different rights once they become CVS Health stockholders due to differences between the organizational documents of CVS Health and Aetna and differences between Delaware law, under which CVS Health is incorporated, and Pennsylvania law, under which Aetna is incorporated. These differences are described in more detail under “Comparison of Stockholder Rights” beginning on page 225 of this joint proxy statement/prospectus.

Litigation Relating to the Merger (see page 176)

As of February 8, 2018, seven complaints had been filed by purported Aetna shareholders challenging the merger. The first, a putative class action complaint, was filed by Olivier Miramond in the United States District Court for the District of Connecticut and is captioned Miramond v. Aetna, Inc., et al., case number 3:18-cv-00083. The second complaint, filed in the United States District Court for the District of Connecticut by Shiva Stein individually, is captioned Stein v. Aetna, Inc., et al., case number 3:18-cv-00136. The third complaint, a putative class action, was filed by Robert Freedman in the United States District Court for the Eastern District of Pennsylvania and is captioned Freedman v. Aetna, Inc., et al., case number 2:18-cv-00323. The fourth complaint, filed in the United States District Court for the District of Connecticut by Luan Pham individually, is captioned Pham v. Aetna, Inc., et al., case number 3:18-cv-00154. The fifth complaint, filed in the United States District Court for the Eastern District of Pennsylvania by Vladimir Gusinsky Rev. Trust individually, is captioned Vladimir Gusinsky Rev. Trust v. Aetna Inc. et al., case number 2:18-cv-00361. The sixth complaint, a putative class action complaint, was filed by Dr. Eli Inzlicht-Sprei in the United States District Court for the District of Connecticut and is captioned Inzlicht-Sprei v. Aetna, Inc., et al., case number 3:18-cv-00176. The seventh complaint, a putative class action complaint, was filed by Joel Rosenfeld in the United States District Court for the District of Connecticut and is captioned Rosenfeld v. Aetna, Inc., et al., case number 3:18-cv-00213. The complaints name as defendants Aetna and each member of Aetna’s board of directors. In addition, the Vladimir Gusinsky Rev. Trust complaint names CVS Health and Merger Sub as defendants. The complaints generally allege, among other things, that the merger consideration in the proposed transaction is unfair, inadequate and undervalues Aetna; that the defendants failed to conduct a fair and reasonable sales process; that the merger agreement’s deal protection provisions improperly deter other suitors from submitting a superior offer for Aetna; that Aetna’s board of directors and executive officers are conflicted because they have secured unique benefits for themselves from the proposed transaction not available to Aetna shareholders generally; and that the defendants authorized the filing of a materially incomplete and misleading registration statement. Among other remedies, the complaints seek to enjoin the Aetna special meeting and the closing of the merger, as well as costs and attorneys’ fees. Defendants believe that the complaints are without merit.

Risk Factors (see page 62)

You should also carefully consider the risks that are described in the section entitled “Risk Factors” beginning on page 62 of this joint proxy statement/prospectus.