Exhibit 4.5
 
 Description of Securities Registered Pursuant to Section 12 of the Securities Exchange Act of 1934
 
 Description of Capital Stock
 
 As of December 31, 2019, PPD, Inc., a Delaware corporation (the “Company,” “we,” “our” or “us”), had one class of securities registered under Section 12 of the Securities Exchange Act of 1934, as amended: common stock, par value $0.01 per share. The following summary includes a brief description of the common stock, as well as certain related additional information. The summary is not complete and is qualified in its entirety by reference to our amended and restated certificate of incorporation and amended and restated bylaws, which are filed as exhibits to this Annual Report on Form 10-K and are incorporated by reference herein.
 
 Capitalization
 
 Pursuant to our amended and restated certificate of incorporation, our authorized capital stock consists of (i) 2,000,000,000 shares of common stock, par value $0.01 per share, and (ii) 100,000,000 shares of preferred stock, par value $0.01 per share.
 
 Common Stock
 Holders of our common stock are entitled to one vote for each share held of record on all matters on which stockholders are entitled to vote generally, including the election or removal of directors. The holders of our common stock do not have cumulative voting rights in the election of directors.
 Preferred Stock
 Our amended and restated certificate of incorporation authorizes our board of directors to establish one or more series of preferred stock (including convertible preferred stock). Unless required by law or by the rules of the Nasdaq Global Select Market, the authorized shares of preferred stock are available for issuance without further action by holders of our common stock, and holders of our common stock are not entitled to vote on any amendment to our amended and restated certificate of incorporation that relates solely to the terms of any outstanding shares of preferred stock, if the holders of such shares of preferred stock are entitled to vote thereon. Our board of directors is authorized to determine, with respect to any series of preferred stock, the powers (including voting powers), preferences and relative, participating, optional and other special rights, and the qualifications, limitations or restrictions thereof as the board of directors may from time to time determine, which could affect the relative voting power or other rights of the holders of our common stock.
 We could issue a series of preferred stock that could, depending on the terms of the series, impede or discourage an acquisition attempt or other transaction that some, or a majority, of the holders of our common stock might believe to be in their best interests or in which the holders of our common stock might receive a premium for their common stock over the market
 
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 price of the common stock. Additionally, the issuance of preferred stock may adversely affect the holders of our common stock, including, without limitation, by restricting dividends on the common stock, diluting the voting power of the common stock or subordinating the liquidation rights of the common stock. As a result of these or other factors, the issuance of preferred stock could have an adverse impact on the market price of our common stock.
 Liquidation Rights
 Upon our dissolution, liquidation or winding up and after payment in full of all amounts required to be paid to creditors and subject to the rights of the holders of one or more outstanding series of preferred stock having liquidation preferences, if any, the holders of our common stock are entitled to receive pro rata our remaining assets available for distribution. Holders of our common stock do not have preemptive, subscription, redemption sinking fund or conversion rights. The common stock is not subject to further calls or assessment by us. All shares of our common stock outstanding are fully paid and non-assessable. The rights, powers, preferences and privileges of holders of our common stock are subject to those of the holders of any shares of our preferred stock or any series or class of stock we may authorize and issue in the future.
 Dividend Rights
 Holders of our common stock are entitled to receive dividends when, as and if declared by our board of directors out of funds legally available therefor, subject to any statutory or contractual restrictions on the payment of dividends and to the rights of the holders or one or more outstanding series of our preferred stock.
 Other Rights
 
 Our common stock has no conversion rights, sinking fund provisions, redemption provisions or preemptive rights.
 
 Certain Anti-Takeover Effects
 
 Certain provisions of the Delaware General Corporation Law (“DGCL”), our amended and restated certificate of incorporation and our amended and restated bylaws summarized in the paragraphs above and in the following paragraphs may have an anti-takeover effect, especially with respect to certain rights held by The Carlyle Group Inc. and its affiliates and Hellman & Friedman LLC and its affiliates (collectively, the “Majority Sponsors”). In other words, such provisions could delay, defer or prevent a tender offer or takeover attempt that a stockholder might consider in its best interests, including those attempts that might result in a premium over the market price for the shares held by such stockholder.
 
 Authorized but Unissued Capital Stock
 Our board of directors may generally issue one or more series of preferred shares on terms that could discourage, delay or prevent a change of control of our Company or the removal of our management.
 
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 Classified Board of Directors
 Our amended and restated certificate of incorporation provides that, subject to the right of holders of any series of preferred stock, our board of directors will be divided into three classes of directors, with the classes to be as nearly equal in number as possible, and with the directors serving staggered three-year terms, with only one class of directors being elected at each annual meeting of stockholders. As a result, approximately one-third of our board of directors will be elected each year.
 Our amended and restated certificate of incorporation and amended and restated bylaws provide that, subject to any rights of holders of preferred stock to elect additional directors under specified circumstances, the number of directors will be fixed from time to time exclusively pursuant to a resolution adopted by the board of directors; however, if at any time the Majority Sponsors beneficially own, in the aggregate, at least 40% in voting power of the stock of our Company entitled to vote generally in the election of directors, the stockholders may also fix the number of directors.
 Removal of Directors; Vacancies
 Our amended and restated certificate of incorporation provides that, other than directors elected by holders of our preferred stock, if any, directors may be removed with or without cause upon the affirmative vote of a majority in voting power of all outstanding shares of stock entitled to vote thereon, voting together as a single class; provided, however, at any time when the Majority Sponsors own, in the aggregate, less than 40% in voting power of the stock of our Company entitled to vote generally in the election of directors, directors may only be removed for cause, and only by the affirmative vote of holders of at least 66 2/3% in voting power of all the then-outstanding shares of stock of our Company entitled to vote thereon, voting together as a single class.
 In addition, our amended and restated certificate of incorporation provides that, subject to the rights granted to one or more series of preferred stock then outstanding, any newly created directorship on the board of directors that results from an increase in the number of directors and any vacancies on our board of directors will be filled only by the affirmative vote of a majority of the remaining directors, even if less than a quorum, or by a sole remaining director or by the stockholders; provided, however, at any time when the Majority Sponsors beneficially own, in the aggregate, less than 40% in voting power of the stock of our Company entitled to vote generally in the election of directors, any newly created directorship on the board of directors that results from an increase in the number of directors and any vacancy occurring in the board of directors may only be filled by a majority of the directors then in office, although less than a quorum, or by a sole remaining director (and not by the stockholders). Our amended and restated certificate of incorporation provides that the board of directors may increase the number of directors by the affirmative vote of a majority of the directors or, at any time when the Majority Sponsors beneficially own, in the aggregate, at least 40% of the voting power of the stock of our Company entitled to vote generally in the election of directors, of the stockholders.
 Business Combinations
 
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 We have opted out of Section 203 of the DGCL; however, our amended and restated certificate of incorporation contains similar provisions providing that we may not engage in certain “business combinations” with any “interested stockholder” for a three-year period following the time that the stockholder became an interested stockholder, unless:
 •prior to such time, our board of directors approved either the business combination or the transaction that resulted in the stockholder becoming an interested stockholder; •upon consummation of the transaction which resulted in the stockholder becoming an interested stockholder, the interested stockholder owned at least 85% of our voting stock outstanding at the time the transaction commenced, excluding certain shares; •at or subsequent to that time, the business combination is approved by our board of directors and by the affirmative vote of holders of at least 66 2/3% of our outstanding voting stock that is not owned by the interested stockholder; or •the stockholder became an interested stockholder inadvertently and (i) as soon as practicable divested itself of sufficient ownership to cease to be an interested stockholder and (ii) had not been an interested stockholder but for the inadvertent acquisition of ownership within three years of the business combination. Generally, a “business combination” includes a merger, asset or stock sale or other transaction resulting in a financial benefit to the interested stockholder. Subject to certain exceptions, an “interested stockholder” is a person who, together with that person’s affiliates and associates, owns, or within the previous three years owned, 15% or more of our outstanding voting stock. For purposes of this section only, “voting stock” has the meaning given to it in Section 203 of the DGCL.
 Our amended and restated certificate of incorporation provides that the Majority Sponsors, and any of their respective direct or indirect transferees and any group as to which such persons or entities are a party, do not constitute “interested stockholders” for purposes of this provision.
 No Cumulative Voting
 Our amended and restated certificate of incorporation does not authorize cumulative voting.
 Special Stockholder Meetings
 Our amended and restated certificate of incorporation provides that special meetings of our stockholders may be called at any time only by or at the direction of the board of directors or the chairman of the board of directors; provided, however, at any time when the Majority Sponsors beneficially own, in the aggregate, at least 40% in voting power of the stock of our Company entitled to vote generally in the election of directors, special meetings of our stockholders shall also be called by the board of directors or the chairman of the board of directors at the request of any of the Majority Sponsors. Our amended and restated bylaws prohibit the conduct of any business at a special meeting other than as specified in the notice for such meeting.
 
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 Requirements for Advance Notification of Director Nominations and Stockholder Proposals
 Our amended and restated bylaws establish advance notice procedures with respect to stockholder proposals and the nomination of candidates for election as directors, other than nominations made by or at the direction of the board of directors or a committee of the board of directors.
 Stockholder Action by Written Consent
 Our amended and restated certificate of incorporation precludes stockholder action by written consent at any time when the Majority Sponsors beneficially own, in the aggregate, less than 40% in voting power of the stock of our Company entitled to vote generally in the election of directors, other than certain rights that holders of our preferred stock may have to act by written consent.
 Supermajority Provisions
 Our amended and restated certificate of incorporation and amended and restated bylaws provide that the board of directors is expressly authorized to make, alter, amend, change, add to, rescind or repeal, in whole or in part, our bylaws without a stockholder vote in any matter not inconsistent with Delaware law or our amended and restated certificate of incorporation. In addition, for as long as the Majority Sponsors beneficially own, in the aggregate, at least 40% in voting power of the stock of our Company entitled to vote generally in the election of directors, any amendment, alteration, rescission or repeal of our bylaws by our stockholders requires the affirmative vote of a majority in voting power of the outstanding shares of our stock present in person or represented by proxy at the meeting of stockholders and entitled to vote on such amendment, alteration, change, addition, rescission, change, addition or repeal.
 Our amended and restated certificate of incorporation provides that at any time when the Majority Sponsors beneficially own, in the aggregate, less than 40% in voting power of the stock of our Company entitled to vote generally in the election of directors, certain provisions in our amended and restated certificate of incorporation may be amended, altered, repealed or rescinded only by the affirmative vote of the holders of at least 66 2/3% in voting power of all the then-outstanding shares of stock of our Company entitled to vote thereon, voting together as a single class.
 Exclusive Forum
 Our amended and restated bylaws provide that unless we consent in writing to the selection of an alternative forum, the Court of Chancery of the State of Delaware shall, to the fullest extent permitted by law, be the sole and exclusive forum for any (i) derivative action or proceeding brought on behalf of our Company, (ii) action asserting a claim of breach of a fiduciary duty owed by any director, officer or other employee of our Company to our Company or our Company’s stockholders, (iii) action asserting a claim against our Company or any director, officer or other employee of our Company arising pursuant to any provision of the DGCL or our amended and restated certificate of incorporation or our amended and restated
 
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 bylaws or as to which the DGCL confers jurisdiction on the Court of Chancery of the State of Delaware or (iv) action asserting a claim against our Company or any director, officer or other employee of our Company governed by the internal affairs doctrine. However, it is possible that a court could find our forum selection provisions to be inapplicable or unenforceable.
 Transfer Agent and Registrar
 
 The transfer agent and registrar for our common stock is Broadridge Corporate Issuer Solutions, Inc.
 
 Nasdaq Listing
 
 Our common stock is listed on The Nasdaq Global Select Market under the symbol “PPD.”