Document:

EX-10.7

 Exhibit 10.7 

SUBSCRIPTION AGREEMENT 

[Other Investors / VC Investors] 

This SUBSCRIPTION AGREEMENT (this “Subscription Agreement”) is entered into on March 7, 2021, by and between dMY
Technology Group, Inc. III (the “Company”), a Delaware corporation, and the undersigned subscriber (“Subscriber”). 

WHEREAS, concurrently with the execution of this Subscription Agreement, the Company is entering into a definitive agreement with IonQ, Inc.,
a Delaware corporation (“IonQ”), and the other parties thereto, in substantially the form previously provided to Subscriber, providing for the combination of the Company and IonQ (as may be amended or supplemented from time to time,
the “Transaction Agreement,” and the transactions contemplated by the Transaction Agreement, the “Transaction”); 

WHEREAS, in connection with the Transaction, Subscriber desires to subscribe for and purchase from the Company, immediately prior to the
consummation of the Transaction, that number of shares of the Company’s Class A common stock, par value $0.0001 per share (the “Shares” or “Class A common stock”), set forth on the
signature page hereto (the “Subscribed Shares”) for a purchase price of $10.00 per share (the “Per Share Price” and the aggregate of such Per Share Price for all Subscribed Shares being referred to herein as the
“Purchase Price”), and the Company desires to issue and sell to Subscriber the Subscribed Shares in consideration of the payment of the Purchase Price by or on behalf of Subscriber to the Company at or prior to the Closing Date (as
defined herein); and 
 WHEREAS, on or about the date of this Subscription Agreement, the Company is entering into subscription agreements
(the “Other Subscription Agreements” and together with the Subscription Agreement, the “Subscription Agreements”) with certain other investors (the “Other Subscribers” and together with Subscriber,
the “Subscribers”), pursuant to which such Subscribers have agreed to purchase on the closing date of the Transaction, inclusive of the Subscribed Shares, an aggregate amount of up to 35,000,000 Shares, at the Per Share Price (the
shares of the Other Subscribers, the “Other Subscribed Shares” and together with the Subscribed Shares, the “Collective Subscribed Shares”). 

NOW, THEREFORE, in consideration of the foregoing and the mutual representations, warranties and covenants, and subject to the conditions,
herein contained, and intending to be legally bound hereby, the parties hereto hereby agree as follows: 
 Section 1
Subscription. Subject to the terms and conditions hereof, at the Closing (as defined below), Subscriber hereby agrees to subscribe for and purchase, and the Company hereby agrees to issue and sell to Subscriber, upon the payment of the
Purchase Price, the Subscribed Shares (such subscription and issuance, the “Subscription”). 
 Section 2
Closing. 
 (a) The consummation of the Subscription contemplated hereby (the “Closing”) shall occur on the closing
date of the Transaction (the “Closing Date”), immediately prior to or substantially concurrently with, but in any event not after, the consummation of the Transaction. 

 (b) At least five (5) Business Days before the anticipated Closing Date, the Company
shall deliver written notice to Subscriber (the “Closing Notice”) specifying (i) the anticipated Closing Date and (ii) the wire instructions for delivery of the Purchase Price to the Company. No later than two
(2) Business Days prior to the Closing Date, Subscriber shall deliver the Purchase Price for the Subscribed Shares by wire transfer of United States dollars in immediately available funds to the account specified by the Company in the Closing
Notice, such funds to be held by the Company in escrow until the Closing, and deliver to the Company such information as is required in the Closing Notice in order for the Company to issue the Subscribed Shares to Subscriber, including, without
limitation, the legal name of the person in whose name the Subscribed Shares are to be issued and a duly completed and executed Internal Revenue Service Form W-9 or appropriate Form W-8. Upon satisfaction (or, if applicable, waiver) of the conditions set forth in this Section 2, the Company shall deliver to Subscriber (i) at the Closing, the Subscribed Shares in
book entry form, free and clear of any liens or other restrictions (other than those arising under this Subscription Agreement or applicable securities laws), in the name of Subscriber (or its nominee in accordance with its delivery instructions),
and (ii) as promptly as practicable after the Closing, evidence from the Company’s transfer agent of the issuance to Subscriber of the Subscribed Shares on and as of the Closing Date. In the event that (i) the Company does not accept
the subscription or (ii) the consummation of the Transaction does not occur within ten (10) Business Days after the anticipated Closing Date specified in the Closing Notice, unless otherwise agreed to in writing by the Company and the
Subscriber, the Company shall promptly (but in no event later than twelve (12) Business Days after the anticipated Closing Date specified in the Closing Notice) return the funds so delivered by Subscriber to the Company by wire transfer in
immediately available funds to the account specified by Subscriber, and any book entries shall be deemed cancelled. Notwithstanding such return or cancellation (x) a failure to close on the anticipated Closing Date shall not, by itself, be
deemed to be a failure of any of the conditions to Closing set forth in this Section 2 to be satisfied or waived on or prior to the Closing Date, and (y) unless and until this Subscription Agreement is terminated in
accordance with Section 7 herein, Subscriber shall remain obligated (A) to redeliver funds to the Company in escrow following the Company’s delivery to Subscriber of a new Closing Notice and (B) to consummate
the Closing upon satisfaction of the conditions set forth in this Section 2. For the purposes of this Subscription Agreement, “Business Day” means any day other than a Saturday, Sunday or any other day on
which the Federal Reserve Bank of New York is closed. Any funds held in escrow by the Company will be uninvested, and the Subscriber shall not be entitled to any interest earned thereon. 

(c) The Closing shall be subject to the satisfaction, or valid waiver by each of the parties hereto, of the conditions that, on the Closing
Date: 
  

	 	(i)	 no suspension of the qualification of the Subscribed Shares for offering or sale or trading in any
jurisdiction, or initiation or threatening of any proceedings for any of such purposes, shall have occurred; 

  

	 	(ii)	 the terms of the Transaction Agreement (including the conditions thereto) shall not have been amended or waived
in a manner that is materially adverse to the Subscriber (in its capacity as such); 

  
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	 	(iii)	 all conditions precedent to the closing of the Transaction set forth in the Transaction Agreement, including
the approval of the Company’s stockholders, shall have been satisfied (as determined by the parties to the Transaction Agreement) or waived (other than those conditions which, by their nature, are to be satisfied at the closing of the
Transaction pursuant to the Transaction Agreement), and the closing of the Transaction shall be scheduled to occur substantially concurrently with or immediately following the Closing; and 

 

	 	(iv)	 no governmental authority shall have enacted, issued, promulgated, enforced or entered any judgment, order,
law, rule or regulation which is then in effect and has the effect of making the consummation of the transactions contemplated hereby illegal or otherwise restraining or prohibiting consummation of the transactions contemplated hereby.

 (d) The obligation of the Company to consummate the Closing shall be subject to the satisfaction or valid waiver by the
Company of the additional conditions that, on the Closing Date: 
  

	 	(i)	 all representations and warranties of Subscriber contained in this Subscription Agreement shall be true and
correct in all material respects (other than representations and warranties that are qualified as to materiality or Subscriber Material Adverse Effect (as defined below), which representations and warranties shall be true and correct in all
respects) at and as of the Closing Date; and 

  

	 	(ii)	 Subscriber shall have performed, satisfied and complied in all material respects with all covenants, agreements
and conditions required by this Subscription Agreement to be performed, satisfied or complied with by it at or prior to the Closing. 

(e) The obligation of Subscriber to consummate the Closing shall be subject to the satisfaction or valid waiver by Subscriber of the additional
conditions that, on the Closing Date: 
  

	 	(i)	 all representations and warranties of the Company contained in this Subscription Agreement shall be true and
correct in all material respects (other than representations and warranties that are qualified as to materiality or Company Material Adverse Effect (as defined below), which representations and warranties shall be true and correct in all respects)
at and as of the Closing Date; and 

  

	 	(ii)	 the Company shall have performed, satisfied and complied in all material respects with all covenants,
agreements and conditions required by this Subscription Agreement to be performed, satisfied or complied with by it at or prior to the Closing. 

  
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 Section 3 Company Representations and Warranties. The Company represents
and warrants to Subscriber and the Placement Agent that: 
 (a) The Company (i) is duly organized, validly existing and in good standing
under the laws of its jurisdiction of incorporation, (ii) has the requisite power and authority to own, lease and operate its properties, to carry on its business as it is now being conducted and to enter into, deliver and perform its
obligations under this Subscription Agreement, and (iii) is duly licensed or qualified to conduct its business and, if applicable, is in good standing under the laws of each jurisdiction (other than its jurisdiction of incorporation) in which
the conduct of its business or the ownership of its properties or assets requires such license or qualification, except, with respect to the foregoing clause (iii), where the failure to be in good standing would not reasonably be expected to
have a Company Material Adverse Effect. For purposes of this Subscription Agreement, a “Company Material Adverse Effect” means an event, change, development, occurrence, condition or effect with respect to the Company and its
subsidiaries, taken together as a whole (on a consolidated basis), that, individually or in the aggregate, would reasonably be expected to have a material adverse effect on the business, properties, general affairs, management, financial position,
stockholders’ equity, or results of operations of the Company and its subsidiaries taken as a whole, or on the Company’s ability to consummate the transactions contemplated hereby, including the issuance and sale of the Subscribed Shares.

 (b) As of the Closing Date, the Subscribed Shares will be duly authorized and, when issued and delivered to Subscriber against full
payment therefor in accordance with the terms of this Subscription Agreement, will be validly issued, fully paid and non-assessable and will not have been issued in violation of any preemptive or similar
rights created under the Company’s organizational documents (as adopted on or prior to the Closing Date), by contract or the laws of its jurisdiction of incorporation. 

(c) This Subscription Agreement has been duly authorized, executed and delivered by the Company, and assuming the due authorization, execution
and delivery of the same by Subscriber, this Subscription Agreement shall constitute the valid and legally binding obligation of the Company, enforceable against the Company in accordance with its terms, except as such enforceability may be limited
by bankruptcy, insolvency, reorganization, moratorium and similar laws affecting creditors generally and by the availability of equitable remedies. 

(d) Assuming the accuracy of the representations and warranties of Subscriber, the execution and delivery of this Subscription Agreement, the
issuance and sale of the Subscribed Shares and the compliance by the Company with all of the provisions of this Subscription Agreement and the consummation of the transactions contemplated herein will not conflict with or result in a breach or
violation of any of the terms or provisions of, or constitute a default under, or result in the creation or imposition of any lien, charge or encumbrance upon any of the property or assets of the Company or any of its subsidiaries pursuant to the
terms of (i) any indenture, mortgage, deed of trust, loan agreement, lease, license or other agreement or instrument to which the Company is a party or by which the Company or any of its subsidiaries is bound or to which any of the property or
assets of the Company or any of its subsidiaries is subject; (ii) the organizational documents of the Company or any of its subsidiaries; or (iii) any statute or any judgment, order, rule or regulation of any court or governmental agency
or body, domestic or foreign, having jurisdiction over the Company or any of its subsidiaries or any of their properties that, in the case of clauses (i) and (iii), would reasonably be expected to have a Company Material Adverse
Effect. 

  
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 (e) Assuming the accuracy of the representations and warranties of Subscriber, the Company
is not required to obtain any consent, waiver, authorization or order of, give any notice to, or make any filing or registration with, any court or other federal, state, local or other governmental authority, self-regulatory organization (including
New York Stock Exchange (the “Stock Exchange”)) or other person in connection with the execution, delivery and performance of this Subscription Agreement (including, without limitation, the issuance of the Subscribed Shares), other
than (i) filings required by applicable state securities laws, (ii) the filing of the Registration Statement pursuant to Section 5 below, (iii) the filing of a Notice of Exempt Offering of Securities on Form
D with the United States Securities and Exchange Commission (“Commission”) under Regulation D of the Securities Act of 1933, as amended (the “Securities Act”), if applicable, (iv) those required by the Stock
Exchange, including with respect to obtaining stockholder approval, (v) those required to consummate the Transaction as provided under the Transaction Agreement, (vi) the filing of notification under the Hart-Scott-Rodino Antitrust
Improvements Act of 1976, if applicable, and (vii) the failure of which to obtain would not be reasonably likely to have a Company Material Adverse Effect. 

(f) As of their respective dates, all reports (the “SEC Reports”) required to be filed by the Company with the Commission
complied in all material respects with the applicable requirements of the Securities Act and/or the Securities Exchange Act of 1934, as amended (the “Exchange Act”), and the rules and regulations of the Commission promulgated
thereunder, and none of the SEC Reports, when filed, contained any untrue statement of a material fact or omitted to state a material fact required to be stated therein or necessary in order to make the statements therein, in the light of the
circumstances under which they were made, not misleading. The financial statements of the Company included in the SEC Reports comply in all material respects with applicable accounting requirements and the rules and regulations of the Commission
with respect thereto as in effect at the time of filing and fairly present in all material respects the financial position of the Company as of and for the dates thereof and the results of operations and cash flows for the periods then ended,
subject, in the case of unaudited statements, to normal, year-end audit adjustments. A copy of each SEC Report is available to the Subscriber via the Commission’s EDGAR system. The Company has timely
filed each report, statement, schedule, prospectus, and registration statement that the Company was required to file with the Commission since its initial registration of the Class A common stock with the Commission. There are no material
outstanding or unresolved comments in comment letters from the staff of the Division of Corporation Finance of the Commission with respect to any of the SEC Reports. 

(g) Except for such matters as have not had and would not be reasonably likely to have a Company Material Adverse Effect, there is no
(i) suit, action, claim or other proceeding or arbitration before a governmental authority or arbitrator pending, or, to the knowledge of the Company, threatened in writing against the Company or any of its subsidiaries or (ii) judgment,
decree, injunction, ruling or order of any governmental authority or arbitrator outstanding against the Company or any of its subsidiaries. 

(h) Assuming the accuracy of Subscriber’s representations and warranties set forth in Section 4 of this
Subscription Agreement, no registration under the Securities Act is required for the offer and sale of the Subscribed Shares by the Company to Subscriber. 

(i) Neither the Company nor any person acting on its behalf has engaged or will engage in any form of general solicitation or general
advertising (within the meaning of Regulation D) in connection with any offer or sale of the Subscribed Shares. 

  
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 (j) Except for Needham & Company, LLC (the “Placement Agent”), no
broker or finder is entitled to any brokerage or finder’s fee or commission solely in connection with the sale of the Subscribed Shares to Subscriber. 

(k) As of the date hereof, the shares of the Company’s Class A common stock are registered pursuant to Section 12(b) of the
Securities Exchange Act, and are listed for trading on the Stock Exchange under the symbol “DMYI.” There is no suit, action, proceeding or investigation pending or, to the knowledge of the Company, threatened against the Company by NYSE or
the Commission with respect to any intention by such entity to deregister the Shares or prohibit or terminate the listing of the Shares on NYSE. The Company has taken no action that is designed to terminate the registration of the Shares under the
Exchange Act. 
 Section 4 Subscriber Representations and Warranties. Subscriber represents and warrants to the Company
and the Placement Agent that: 
 (a) Subscriber (i) is either (x) a corporate entity duly organized, validly existing and in good
standing under the laws of its jurisdiction of incorporation or (y) a natural person, and (ii) has the requisite power and authority to enter into and perform its obligations under this Subscription Agreement. 

(b) This Subscription Agreement has been duly executed and delivered by Subscriber, and assuming the due authorization, execution and delivery
of the same by the Company, this Subscription Agreement shall constitute the valid and legally binding obligation of Subscriber, enforceable against Subscriber in accordance with its terms, except as such enforceability may be limited by bankruptcy,
insolvency, reorganization, moratorium and similar laws affecting creditors generally and by the availability of equitable remedies. 
 (c)
The execution and delivery of this Subscription Agreement, the purchase of the Subscribed Shares and the compliance by Subscriber with all of the provisions of this Subscription Agreement and the consummation of the transactions contemplated herein
will not conflict with or result in a breach or violation of any of the terms or provisions of, or constitute a default under, or result in the creation or imposition of any lien, charge or encumbrance upon any of the property or assets of
Subscriber pursuant to the terms of (i) any indenture, mortgage, deed of trust, loan agreement, lease, license or other agreement or instrument to which Subscriber is a party or by which Subscriber is bound or to which any of the property or
assets of Subscriber is subject; (ii) the organizational documents of Subscriber; or (iii) any statute or any judgment, order, rule or regulation of any court or governmental agency or body, domestic or foreign, having jurisdiction over
Subscriber or any of its properties that, in the case of clauses (i) and (iii), would reasonably be expected to have a Subscriber Material Adverse Effect. For purposes of this Subscription Agreement, a “Subscriber Material
Adverse Effect” means an event, change, development, occurrence, condition or effect with respect to Subscriber that would reasonably be expected to have a material adverse effect on Subscriber’s ability to consummate the transactions
contemplated hereby, including the purchase of the Subscribed Shares. 
 (d) Subscriber (i) is a “qualified institutional
buyer” (as defined in Rule 144A under the Securities Act) or an “accredited investor” (within the meaning of Rule 501(a)(1), (2), (3), (5), (6), (7) or (8) under the Securities Act), in each case, satisfying the applicable
requirements set forth on Annex A, (ii) is acquiring the Subscribed Shares only for its own account and not for 

  
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the account of others, or if Subscriber is subscribing for the Subscribed Shares as a fiduciary or agent for one or more investor accounts, each owner of such account is a qualified institutional
buyer and Subscriber has full investment discretion with respect to each such account, and the full power and authority to make the acknowledgements, representations and agreements herein on behalf of each owner of each such account, and
(iii) is not acquiring the Subscribed Shares with a view to, or for offer or sale in connection with, any distribution thereof in violation of the Securities Act (and has provided the Company with the requested information on Annex A following
the signature page hereto). Subscriber is not an “institutional account” as defined by FINRA Rule 4512(c). 
 (e) Subscriber
understands that the Subscribed Shares are being offered in a transaction not involving any public offering within the meaning of the Securities Act and that the Subscribed Shares have not been registered under the Securities Act. Subscriber
understands that the Subscribed Shares may not be offered, resold, transferred, pledged or otherwise disposed of by Subscriber absent an effective registration statement under the Securities Act, except (i) to the Company or a subsidiary
thereof, or (ii) pursuant to an applicable exemption from the registration requirements of the Securities Act, and, in each of cases (i) and (ii), in accordance with any applicable securities laws of the applicable states and other
jurisdictions of the United States, and that any certificates or book entry records representing the Subscribed Shares shall contain a restrictive legend to such effect. The Subscriber acknowledges and agrees that the Subscribed Shares will be
subject to these securities law transfer restrictions and, as a result of these transfer restrictions, Subscriber may not be able to readily resell the Subscribed Shares and may be required to bear the financial risk of an investment in the
Subscribed Shares for an indefinite period of time. Subscriber acknowledges and agrees that the Subscribed Shares will not be eligible for offer, resale, transfer, pledge or disposition pursuant to Rule 144 promulgated under the Securities Act until
at least one year from the filing of “Form 10 information” with the Commission after the Closing Date. Subscriber understands that it has been advised to consult legal counsel prior to making any offer, resale, pledge or transfer of any of
the Subscribed Shares. 
 (f) Subscriber understands and agrees that Subscriber is purchasing the Subscribed Shares directly from the
Company. Subscriber further acknowledges that there have not been, and Subscriber hereby agrees that it is not relying on, any representations, warranties, covenants or agreements made to Subscriber by the Company, the Placement Agent, any of their
respective affiliates or any control persons, officers, directors, employees, partners, agents or representatives, any other party to the Transaction or any other person or entity, expressly or by implication, other than those representations,
warranties, covenants and agreements of the Company set forth in this Subscription Agreement. Subscriber acknowledges that certain information provided by the Company was based on projections, and such projections were prepared based on assumptions
and estimates that are inherently uncertain and are subject to a wide variety of significant business, economic and competitive risks and uncertainties that could cause actual results to differ materially from those contained in the projections.

  
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 (g) In making its decision to purchase the Subscribed Shares, Subscriber has relied solely
upon independent investigation made by Subscriber. Subscriber acknowledges and agrees that Subscriber has received such information as Subscriber deems necessary in order to make an investment decision with respect to the Subscribed Shares,
including with respect to the Company and the Transaction (including IonQ and its subsidiaries (collectively, the “Acquired Companies”)). Subscriber represents and agrees that Subscriber and Subscriber’s professional
advisor(s), if any, have had the full opportunity to ask such questions, receive such answers and obtain such information as Subscriber and such undersigned’s professional advisor(s), if any, have deemed necessary to make an investment decision
with respect to the Subscribed Shares. Without limiting the generality of the foregoing, the Subscriber acknowledges that it has reviewed the Company’s filings with the Commission. Subscriber acknowledges and agrees that neither the Placement
Agent, nor any affiliate of the Placement Agent, has provided Subscriber with any information or advice with respect to the Subscribed Shares nor is such information or advice necessary or desired. Neither the Placement Agent nor any of its
affiliates has made or makes any representation as to the Company or the Acquired Companies or the quality or value of the Subscribed Shares. The Placement Agent and its affiliates may have acquired non-public
information with respect to the Company or the Acquired Companies which Subscriber agrees need not be provided to it. In connection with the issuance of the Subscribed Shares to Subscriber, neither the Placement Agent nor any of its affiliates has
acted as a financial advisor or fiduciary to Subscriber. The Subscriber agrees the Placement Agent shall not be liable to any Subscriber for any action heretofore or hereafter taken or omitted to be taken by any of them in connection with the
Subscriber’s purchase of the Subscribed Shares. 
 (h) Subscriber became aware of this offering of the Subscribed Shares solely by means
of direct contact between Subscriber and the Company and/or IonQ, or their respective representatives or affiliates, or by means of contact from the Placement Agent and the Subscribed Shares were offered to Subscriber solely by direct contact
between Subscriber and the Company and/or IonQ, or their respective affiliates. Subscriber did not become aware of this offering of the Subscribed Shares, nor were the Subscribed Shares offered to Subscriber, by any other means. Subscriber
acknowledges that the Company represents and warrants that the Subscribed Shares (i) were not offered by any form of general solicitation or general advertising and (ii) are not being offered in a manner involving a public offering under,
or in a distribution in violation of, the Securities Act, or any state securities laws. 
 (i) Subscriber acknowledges that it is aware that
there are substantial risks incident to the purchase and ownership of the Subscribed Shares. Subscriber has such knowledge and experience in financial and business matters as to be capable of evaluating the merits and risks of an investment in the
Subscribed Shares, and Subscriber has had an opportunity to seek, and has sought, such accounting, legal, business and tax advice as Subscriber has considered necessary to make an informed investment decision. 

(j) Subscriber has adequately analyzed and fully considered the risks of an investment in the Subscribed Shares and determined that the
Subscribed Shares are a suitable investment for Subscriber and that Subscriber is able at this time and in the foreseeable future to bear the economic risk of a total loss of Subscriber’s investment in the Company. Subscriber acknowledges
specifically that a possibility of total loss exists. 
 (k) Subscriber understands and agrees that no federal or state agency has passed
upon or endorsed the merits of the offering of the Subscribed Shares or made any findings or determination as to the fairness of this investment. 

  
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 (l) Subscriber is not owned or controlled by or acting on behalf of (in connection with this
Transaction), a Sanctioned Person. Subscriber is not an institution that accepts currency for deposit and that (a) has no physical presence in the jurisdiction in which it is incorporated or in which it is operating and (b) is unaffiliated
with a regulated financial group that is subject to consolidated supervision (a “Shell Bank”) or providing banking services to a Shell Bank. Subscriber represents that if it is a financial institution subject to the Bank Secrecy Act
(31 U.S.C. Section 5311 et seq.), as amended by the USA PATRIOT Act of 2001 and its implementing regulations (collectively, the “BSA/PATRIOT Act”), that Subscriber maintains policies and procedures reasonably designed to comply
with applicable obligations under the BSA/PATRIOT Act. Subscriber also represents that, to the extent required by applicable law, it maintains, either directly or through the use of a third-party administrator, policies and procedures reasonably
designed for the screening of any investors in the Subscriber against Sanctions-related lists of blocked or restricted persons. Subscriber further represents and warrants that (a) the funds held by Subscriber and used to purchase the Subscribed
Shares were not directly or indirectly derived from or related to any activities that may contravene U.S. federal, state or non-U.S. anti-money laundering, anti-corruption or Sanctions laws and regulations or
activities that may otherwise be deemed criminal and (b) any returns from the Subscriber’s investment will not be used to finance any illegal activities. For purposes of this Agreement, “Sanctioned Person” means at any time any
person or entity with whom dealings are restricted, prohibited, or sanctionable under any Sanctions (as defined below), including as a result of being: (a) listed on any Sanctions-related list of designated or blocked or restricted persons;
(b) that is a national of, the government of, or any agency or instrumentality of the government of, or resident in, or organized under the laws of, a country or territory that is the target of comprehensive Sanctions from time to time (as of
the date of this Agreement, Cuba, Iran, North Korea, Syria, and the Crimea region); or (c) a relationship of ownership, control, or agency with any of the foregoing. “Sanctions” means those trade, economic and financial sanctions
laws, regulations, embargoes, and restrictive measures (in each case having the force of law) administered, enacted or enforced from time to time by (a) the United States (including without limitation the U.S. Department of the Treasury, Office
of Foreign Assets Control, the U.S. Department of State, and the U.S. Department of Commerce), (b) the European Union and enforced by its member states, (c) the United Nations and (d) the United Kingdom. 

(m) Subscriber is not owned or controlled by or acting on behalf of (in connection with this Transaction), a person or entity resident in, or
whose funds used to purchase the Subscribed Shares are transferred from or through, a country, territory or entity that (i) has been designated as non-cooperative with international anti-money laundering
or counter terrorist financing principles or procedures by the United States or by an intergovernmental group or organization, such as the Financial Action Task Force, of which the United States is a member; (ii) is the subject of an advisory
issued by the Financial Crimes Enforcement Network of the U.S. Department of the Treasury; or (iii) has been designated by the Secretary of the Treasury under Section 311 of the USA PATRIOT Act as warranting special measures due to money
laundering concerns (any such country or territory, a “Non-cooperative Jurisdiction”), or an entity or individual that resides or has a place of business in, or is organized under the laws of, a Non-cooperative Jurisdiction. 

  
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 (n) Subscriber does not have, as of the date hereof, and during the 30-day period immediately prior to the date hereof such Subscriber has not entered into, any “put equivalent position” as such term is defined in Rule 16a-1 under
the Exchange Act or Short Sale positions with respect to the securities of the Company or IonQ. Notwithstanding the foregoing, in the case of a Subscriber that is a multi-managed investment vehicle whereby separate portfolio managers manage separate
portions of such Subscriber’s assets and the portfolio managers have no direct knowledge of the investment decisions made by the portfolio managers managing other portions of such Subscriber’s assets, the representation set forth above
shall only apply with respect to the portion of assets managed by the portfolio manager that made the investment decision to purchase the Subscribed Shares covered by this Agreement. 

(o) Subscriber is not currently (and at all times through Closing will refrain from being or becoming) a member of a “group” (within
the meaning of Section 13(d)(3) or Section 14(d)(2) of the Exchange Act or any successor provision) including any group acting for the purpose of acquiring, holding, voting or disposing of equity securities of the Company or IonQ (within
the meaning of Rule 13d-5(b)(1) under the Exchange Act). 
 (p) If Subscriber is an employee benefit
plan that is subject to Title I of the Employee Retirement Income Security Act of 1974, as amended (“ERISA”), a plan, an individual retirement account or other arrangement that is subject to section 4975 of the Internal Revenue Code of
1986, as amended (the “Code”) or an employee benefit plan that is a governmental plan (as defined in section 3(32) of ERISA), a church plan (as defined in section 3(33) of ERISA), a non-U.S.
plan (as described in section 4(b)(4) of ERISA) or other plan that is not subject to the foregoing but may be subject to provisions under any other federal, state, local, non-U.S. or other laws or regulations
that are similar to such provisions of ERISA or the Code, or an entity whose underlying assets are considered to include “plan assets” of any such plan, account or arrangement (each, a “Plan”) subject to the fiduciary or
prohibited transaction provisions of ERISA or section 4975 of the Code, Subscriber represents and warrants that (i) neither the Company, nor any of its respective affiliates, including dMY Sponsor III, LLC (the “Transaction
Parties”), has acted as the Plan’s fiduciary, or has been relied on for advice, with respect to its decision to acquire and hold the Subscribed Shares, and none of the Transaction Parties shall at any time be relied upon as the
Plan’s fiduciary with respect to any decision to acquire, continue to hold or transfer the Subscribed Shares and (ii) the acquisition and holding of the Subscribed Shares will not result in a
non-exempt prohibited transaction under ERISA or Section 4975 of the Code. 
 (q) Subscriber at
the Closing will have sufficient funds to pay the Purchase Price pursuant to Section 2. 
 (r) Except for the
Placement Agent, no broker or finder is entitled to any brokerage or finder’s fee or commission solely in connection with the sale of the Subscribed Shares to Subscriber. 

(s) Subscriber agrees that the Placement Agent may rely upon the representations and warranties made by Subscriber to the Company in this
Subscription Agreement. 

  
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 Section 5 Registration of Subscribed Shares. 

(a) The Company agrees that, within fifteen (15) Business Days after the Closing Date (the “Filing Date”), the Company
will submit to or file with the Commission (at the Company’s sole cost and expense) a registration statement registering the resale of the Subscribed Shares (the “Registration Statement”) and the Company shall use its
commercially reasonable efforts to have the Registration Statement declared effective as soon as practicable after the filing thereof (and in any event, no later than thirty (30) calendar days following the Filing Date) (the
“Effectiveness Deadline”), provided, that the Effectiveness Deadline shall be extended to sixty (60) calendar days after the Filing Date if the Registration Statement is reviewed by, and comments thereto are provided from, the
Commission; provided, that if such day falls on a Saturday, Sunday or other day that the Commission is closed for business, the Effectiveness Deadline shall be extended to the next Business Day on which the Commission is open for business.
Notwithstanding the foregoing, if the Company is notified (orally or in writing, whichever is earlier) by the Commission that the Registration Statement will not be “reviewed” or subject to further review, the Company shall use its
commercially reasonable efforts to have the Registration Statement declared effective within five (5) Business Days of receipt of such notice, or on the Closing Date, if later. Any failure by the Company to file the Registration Statement by
the Filing Date or to effect such Registration Statement by the Effectiveness Deadline shall not otherwise relieve the Company of its obligations to file or effect the Registration Statement as set forth above in this Section 5. The
Company will use its commercially reasonable efforts to provide a draft of the Registration Statement to the undersigned for review (but not comment) at least two (2) Business Days in advance of filing the Registration Statement; provided that,
for the avoidance of doubt, in no event shall the Company be required to delay or postpone the filing of such Registration Statement as a result of or in connection with Subscriber’s review. In no event shall the undersigned be identified as a
statutory underwriter in the Registration Statement unless requested by the Commission; provided, that if the Commission requests that a Subscriber be identified as a statutory underwriter in the Registration Statement, Subscriber will have the
opportunity to withdraw from the Registration Statement. Notwithstanding the foregoing, if the Commission prevents the Company from including any or all of the shares proposed to be registered under the Registration Statement due to limitations on
the use of Rule 415 of the Securities Act for the resale of the Subscribed Shares by the applicable stockholders or otherwise, such Registration Statement shall register for resale such number of Subscribed Shares which is equal to the maximum
number of Subscribed Shares as is permitted by the Commission. In such event, the number of Subscribed Shares to be registered for each selling stockholder named in the Registration Statement shall be reduced pro rata among all such selling
stockholders. The Company agrees that, except for such times as the Company is permitted hereunder to suspend the use of the prospectus forming part of a Registration Statement, the Company will use commercially reasonable efforts to cause such
Registration Statement to remain effective with respect to Subscriber until the earlier of (i) two (2) years from the issuance of the Subscribed Shares, (ii) the date on which all of the Subscribed Shares shall have been sold, or
(iii) on the first date on which the undersigned can sell all of its Subscribed Shares (or shares received in exchange therefor) under Rule 144 of the Securities Act without limitation as to the manner of sale or the amount of such securities
that may be sold. For as long as the Registration Statement shall remain effective pursuant to the immediately preceding sentence, the Company will use commercially reasonable efforts to file all reports, and provide all customary and reasonable
cooperation, necessary to enable the undersigned to resell the Subscribed Shares pursuant to the Registration Statement or Rule 144 of the Securities Act (when Rule 144 of the Securities Act becomes available to the Company), as applicable, qualify
the Subscribed Shares for listing on 

  
 11 

 
the applicable stock exchange on which the Company’s Shares are then listed, and update or amend the Registration Statement as necessary to include the Subscribed Shares. The undersigned
agrees to disclose its beneficial ownership, as determined in accordance with Rule 13d-3 of the Securities Exchange Act of 1934 (as amended, the “Exchange Act”), of Subscribed Shares to the
Company (or its successor) upon request to assist the Company in making the determination described above. The Company’s obligations to include the Subscribed Shares in the Registration Statement are contingent upon Subscriber furnishing in
writing to the Company such information regarding Subscriber, the securities of the Company held by Subscriber and the intended method of disposition of the Subscribed Shares as shall be reasonably requested by the Company to effect the registration
of the Subscribed Shares, and Subscriber shall execute such documents in connection with such registration as the Company may reasonably request that are customary of a selling stockholder in similar situations, including providing that the Company
shall be entitled to postpone and suspend the effectiveness or use of the Registration Statement during any customary blackout or similar period or as permitted hereunder. In the case of the registration effected by the Company pursuant to this
Subscription Agreement, the Company shall, upon reasonable request, inform Subscriber as to the status of such registration. Subscriber shall not be entitled to use the Registration Statement for an underwritten offering of Subscribed Shares.
Notwithstanding anything to the contrary contained herein, the Company may delay or postpone filing of such Registration Statement, and from time to time require Subscriber not to sell under the Registration Statement or suspend the use or
effectiveness of any such Registration Statement if it determines that in order for the registration statement to not contain a material misstatement or omission, an amendment thereto would be needed, or if such filing or use could materially affect
a bona fide business or financing transaction of the Company or would require premature disclosure of information that could materially adversely affect the Company (each such circumstance, a “Suspension Event”); provided, that,
(x) the Company shall not so delay filing or so suspend the use of the Registration Statement on more than two (2) occasions for a period of more than sixty (60) consecutive days each or more than a total of one hundred-twenty
(120) calendar days, in each case in any three hundred sixty (360) day period and (y) the Company shall use commercially reasonable efforts to make such registration statement available for the sale by the undersigned of such
securities as soon as practicable thereafter. 
 (b) Upon receipt of any written notice from the Company (which notice shall not contain any
material non-public information regarding the Company) of the happening of any Suspension Event during the period that the Registration Statement is effective or if as a result of a Suspension Event the
Registration Statement or related prospectus contains any untrue statement of a material fact or omits to state any material fact required to be stated therein or necessary to make the statements therein, in light of the circumstances under which
they were made (in the case of the prospectus) not misleading, the undersigned agrees that (i) it will immediately discontinue offers and sales of the Subscribed Shares under the Registration Statement (excluding, for the avoidance of doubt,
sales conducted pursuant to Rule 144) until the undersigned receives copies of a supplemental or amended prospectus (which the Company agrees to promptly prepare) that corrects the misstatement(s) or omission(s) referred to above and receives notice
that any post-effective amendment has become effective or unless otherwise notified by the Company that it may resume such offers and sales, and (ii) it will maintain the confidentiality of any information included in such written notice
delivered by the Company unless otherwise required by law, subpoena or regulatory request or requirement. If so directed by the Company, the undersigned will deliver to the Company or, in the undersigned’s sole

  
 12 

 
discretion destroy, all copies of the prospectus covering the Subscribed Shares in the undersigned’s possession; provided, however, that this obligation to deliver or destroy all copies of
the prospectus covering the Subscribed Shares shall not apply (w) to the extent the undersigned is required to retain a copy of such prospectus (A) in order to comply with applicable legal, regulatory, self-regulatory or professional
requirements or (B) in accordance with a bona fide pre-existing document retention policy or (x) to copies stored electronically on archival servers as a result of automatic data back-up. 
 Section 6 Short Sales. Subscriber hereby agrees that, from the date of this
Subscription Agreement, none of Subscriber, its controlled affiliates, or any person or entity acting on behalf of Subscriber or any of its controlled affiliates or pursuant to any understanding with Subscriber or any of its controlled affiliates
will engage in any Short Sales with respect to securities of the Company prior to the Closing. For purposes of this Section 6, “Short Sales” shall include, without limitation, all “short sales” as
defined in Rule 200 promulgated under Regulation SHO under the Exchange Act, and all types of direct and indirect stock pledges (other than pledges in the ordinary course of business as part of prime brokerage arrangements), forward sale contracts,
options, puts, calls, swaps and similar arrangements (including on a total return basis), and sales and other transactions through non-U.S. broker dealers or foreign regulated brokers. Notwithstanding the
foregoing, (i) nothing herein shall prohibit other entities under common management with Subscriber that have no knowledge of this Subscription Agreement or of Subscriber’s participation in the Transaction (including Subscriber’s
controlled affiliates and/or affiliates) from entering into any Short Sales and (ii) in the case of a Subscriber that is a multi-managed investment vehicle whereby separate portfolio managers manage separate portions of such Subscriber’s
assets and the portfolio managers have no knowledge of the investment decisions made by the portfolio managers managing other portions of such Subscriber’s assets, the covenant set forth above shall only apply with respect to the portion of
assets managed by the portfolio manager that made the investment decision to purchase the Subscribed Shares covered by this Subscription Agreement. 

Section 7 Termination. This Subscription Agreement shall terminate and be void and of no further force and effect, and all rights
and obligations of the parties hereunder shall terminate without any further liability on the part of any party in respect thereof, upon the earlier to occur of (a) such date and time as the Transaction Agreement is terminated in accordance
with its terms, (b) upon the mutual written agreement of the parties hereto to terminate this Subscription Agreement or (c) if, on the Closing Date of the Transaction, any of the conditions to Closing set forth in
Section 2 of this Subscription Agreement have not been satisfied as of the time required hereunder to be so satisfied or waived by the party entitled to grant such waiver and, as a result thereof, the transactions
contemplated by this Subscription Agreement are not consummated (the termination events described in clauses (a)-(c) above, collectively, the “Termination Events”); provided, that nothing herein will relieve any party
from liability for any willful breach hereof prior to the time of termination, and each party will be entitled to any remedies at law or in equity to recover losses, liabilities or damages arising from such breach. The Company shall notify
Subscriber of the termination of the Transaction Agreement promptly after the termination thereof. Upon the occurrence of any Termination Event, except as set forth in the proviso to the first sentence of this Section 7,
this Subscription Agreement shall be void and of no further effect and any portion of the Purchase Price paid by the Subscriber to Company in connection herewith shall promptly (and in any event within one (1) business day) following the
Termination Event be returned to the Subscriber. 

  
 13 

 Section 8 Trust Account Waiver. Subscriber hereby acknowledges that the Company
has established a trust account (the “Trust Account”) containing the proceeds of its initial public offering (the “IPO”) and from certain private placements occurring simultaneously with the IPO (including interest
accrued from time to time thereon) for the benefit of the Company’s public stockholders and certain other parties (including the underwriters of the IPO). For and in consideration of the Company entering into this Subscription Agreement, and
for other good and valuable consideration, the receipt and sufficiency of which are hereby acknowledged, Subscriber hereby (a) agrees that it does not now and shall not at any time hereafter have any right, title, interest or claim of any kind
in or to any assets held in the Trust Account, and shall not make any claim against the Trust Account, regardless of whether such claim arises as a result of, in connection with or relating in any way to this Subscription Agreement or any other
matter, and regardless of whether such claim arises based on contract, tort, equity or any other theory of legal liability (any and all such claims are collectively referred to hereafter as the “Released Claims”), (b) irrevocably
waives any Released Claims that it may have against the Trust Account now or in the future as a result of, or arising out of, any negotiations, contracts or agreements with the Company, and (c) will not seek recourse against the Trust Account
for any reason whatsoever; provided, however, that nothing in this Section 8 shall be deemed to limit any Subscriber’s right to distributions from the Trust Account in accordance with the Company’s
amended and restated certificate of incorporation in respect of shares of Class A common stock of the Company acquired by any means other than pursuant to this Subscription Agreement. 

Section 9 Transfer Restrictions. Subscriber agrees that it shall not (i) sell, offer to sell, contract or agree to sell,
hypothecate, pledge, grant any option to purchase or otherwise dispose of or agree to dispose of, directly or indirectly, or establish or increase a put equivalent position or liquidate or decrease a call equivalent position within the meaning of
Section 16 of the Exchange Act, with respect to any Subscribed Shares, (ii) enter into any swap or other arrangement that transfers to another, in whole or in part, any of the economic consequences of ownership of any Subscribed Shares
(clauses (i) and (ii) collectively, a “Transfer”) or (iii) publicly announce any intention to effect any transaction specified in clause (i) or (ii), for a period beginning on the date hereof and ending on the date
that is six (6) months after the Closing (the “Lock-Up Period”), in each case, without the prior written consent of the Company. 

Section 10 Miscellaneous. 

(a) All notices, requests, demands, claims, and other communications hereunder shall be in writing. Any notice, request, demand, claim, or
other communication hereunder shall be deemed duly given (i) when delivered personally to the recipient, (ii) when sent by electronic mail, on the date of transmission to such recipient; provided, that such notice, request, demand, claim
or other communication is also sent to the recipient pursuant to clauses (i), (iii) or (iv) of this Section 10(a), (iii) one (1) Business Day after being sent to the recipient by reputable
overnight courier service (charges prepaid), or (iv) four (4) Business Days after being mailed to the recipient by certified or registered mail, return receipt requested and postage prepaid, and, in each case, addressed to the intended
recipient at its address specified on the signature page hereof or to such electronic mail address or address as subsequently modified by written notice given in accordance with this Section 10(a). A courtesy electronic
copy of any notice sent by methods (i), (iii), or (iv) above shall also be sent to the recipient via electronic mail if provided in the applicable signature page hereof or to an electronic mail address as subsequently modified by written notice
given in accordance with this Section 10(a). 

  
 14 

 (b) Subscriber acknowledges that the Company, IonQ, the Placement Agent and others will rely
on the acknowledgments, understandings, agreements, representations and warranties of Subscriber contained in this Subscription Agreement. Prior to the Closing, Subscriber agrees to promptly notify the Company, IonQ and the Placement Agent if it
becomes aware that any of the acknowledgments, understandings, agreements, representations and warranties of Subscriber set forth herein are no longer accurate in all material respects. Subscriber acknowledges and agrees that each purchase by
Subscriber of Subscribed Shares from the Company will constitute a reaffirmation of the acknowledgments, understandings, agreements, representations and warranties herein (as modified by any such notice) by Subscriber as of the time of such
purchase. The Company acknowledges that Subscriber will rely on the acknowledgments, understandings, agreements, representations and warranties contained in this Subscription Agreement. Prior to the Closing, the Company agrees to promptly notify
Subscriber if it becomes aware that any of the acknowledgments, understandings, agreements, representations and warranties of the Company set forth herein are no longer accurate in all material respects. 

(c) Each of the Company, IonQ, the Placement Agent and Subscriber is irrevocably authorized to produce this Subscription Agreement or a copy
hereof to any interested party in any administrative or legal proceeding or official inquiry with respect to the matters covered hereby. The parties hereto acknowledge and agree that the Placement Agent is a third-party beneficiary of the
acknowledgments, representations, warranties and covenants of the parties contained in this Subscription Agreement. 
 (d) Subscriber shall
pay all of its own expenses in connection with this Subscription Agreement and the transactions contemplated herein. 
 (e) Neither this
Subscription Agreement nor any rights that may accrue to Subscriber hereunder (other than the Subscribed Shares acquired hereunder, if any) may be transferred or assigned. Neither this Subscription Agreement nor any rights that may accrue to the
Company hereunder may be transferred or assigned (provided, that, for the avoidance of doubt, the Company may transfer the Subscription Agreement and its rights hereunder solely in connection with the consummation of the Transaction and exclusively
to another entity under the control of, or under common control with, the Company). Notwithstanding the foregoing, Subscriber may assign its rights and obligations under this Subscription Agreement to one or more of its affiliates (including other
investment funds or accounts managed or advised by the investment manager who acts on behalf of Subscriber) or, with the Company’s prior written consent, to another person, provided that no such assignment shall relieve Subscriber of its
obligations hereunder if any such assignee fails to perform such obligations. 
 (f) All the agreements, representations and warranties made
by each party hereto in this Subscription Agreement shall survive the Closing. For the avoidance of doubt, if for any reason the Closing does not occur prior to the consummation of the Transaction, all representations, warranties, covenants and
agreements of the parties hereunder shall survive the consummation of the Transaction and remain in full force and effect. 

  
 15 

 (g) The Company may request from Subscriber such additional information as the Company may
reasonably deem necessary to evaluate the eligibility of Subscriber to acquire the Subscribed Shares and to register the Subscribed Shares for resale, and Subscriber shall provide such information as may be requested. Subscriber acknowledges that,
subject to the conditions set forth in Section 10(t), the Company may file a copy of this Subscription Agreement with the Commission as an exhibit to a periodic report of the Company or a registration statement of the
Company. 
 (h) This Subscription Agreement may not be amended, modified or waived except by an instrument in writing, signed by each of the
parties hereto. 
 (i) This Subscription Agreement and any non-disclosure agreement entered into by
the parties hereto constitute the entire agreement, and supersedes all other prior agreements, understandings, representations and warranties, both written and oral, among the parties, with respect to the subject matter hereof. 

(j) Except as otherwise provided herein, this Subscription Agreement is intended for the benefit of the parties hereto and their heirs,
executors, administrators, successors, legal representatives, and permitted assigns and is not for the benefit of, nor may any provision hereof be enforced by, any other person. Except as set forth in Section 10(b),
Section 10(c) and this Section 10(j) with respect to the persons specifically referenced therein, this Subscription Agreement shall not confer any rights or remedies upon any person other than the
parties hereto, and their respective successor and assigns, and the parties hereto acknowledge that such persons so referenced are third party beneficiaries of this Subscription Agreement for the purposes of, and to the extent of, the rights granted
to them, if any, pursuant to the applicable provisions. 
 (k) The parties hereto acknowledge and agree that (i) this Subscription
Agreement is being entered into in order to induce the Company to execute and deliver the Transaction Agreement and (ii) irreparable damage would occur in the event that any of the provisions of this Subscription Agreement were not performed in
accordance with their specific terms or were otherwise breached and that money or other legal remedies would not be an adequate remedy for such damage. It is accordingly agreed that the parties shall be entitled to equitable relief, including in the
form of an injunction or injunctions to prevent breaches or threatened breaches of this Subscription Agreement and to enforce specifically the terms and provisions of this Subscription Agreement, this being in addition to any other remedy to which
such party is entitled at law, in equity, in contract, in tort or otherwise. The parties hereto acknowledge and agree that the Company shall be entitled to specifically enforce Subscriber’s obligations to fund the Subscription Amount and the
provisions of the Subscription Agreement, in each case, on the terms and subject to the conditions set forth herein. The parties hereto further acknowledge and agree: (x) to waive any requirement for the security or posting of any bond in
connection with any such equitable remedy; (y) not to assert that a remedy of specific enforcement pursuant to this Section 10(k) is unenforceable, invalid, contrary to applicable law or inequitable for any reason; and
(z) to waive any defenses in any action for specific performance, including the defense that a remedy at law would be adequate. In connection with any proceeding for which the Company is being granted an award of money damages, the Subscriber
agrees that such damages shall include, without limitation, damages related to the consideration that is or was to be paid to IonQ under the Transaction Agreement and such damages are not limited to an award of out-of-pocket fees and expenses related to the Transaction Agreement and this Subscription Agreement. 

  
 16 

 (l) In any dispute arising out of or related to this Subscription Agreement, or any other
agreement, document, instrument or certificate contemplated hereby, or any transactions contemplated hereby or thereby, the applicable adjudicating body shall award to the prevailing party, if any, the costs and attorneys’ fees reasonably
incurred by the prevailing party in connection with the dispute and the enforcement of its rights under this Subscription Agreement or any other agreement, document, instrument or certificate contemplated hereby and, if the adjudicating body
determines a party to be the prevailing party under circumstances where the prevailing party won on some but not all of the claims and counterclaims, the adjudicating body may award the prevailing party an appropriate percentage of the costs and
attorneys’ fees reasonably incurred by the prevailing party in connection with the adjudication and the enforcement of its rights under this Subscription Agreement or any other agreement, document, instrument or certificate contemplated hereby
or thereby. 
 (m) If any provision of this Subscription Agreement shall be invalid, illegal or unenforceable, the validity, legality or
enforceability of the remaining provisions of this Subscription Agreement shall not in any way be affected or impaired thereby and shall continue in full force and effect. 

(n) No failure or delay by a party hereto in exercising any right, power or remedy under this Subscription Agreement, and no course of dealing
between the parties hereto, shall operate as a waiver of any such right, power or remedy of such party. No single or partial exercise of any right, power or remedy under this Subscription Agreement by a party hereto, nor any abandonment or
discontinuance of steps to enforce any such right, power or remedy, shall preclude such party from any other or further exercise thereof or the exercise of any other right, power or remedy hereunder. The election of any remedy by a party hereto
shall not constitute a waiver of the right of such party to pursue other available remedies. No notice to or demand on a party not expressly required under this Subscription Agreement shall entitle the party receiving such notice or demand to any
other or further notice or demand in similar or other circumstances or constitute a waiver of the rights of the party giving such notice or demand to any other or further action in any circumstances without such notice or demand. 

(o) This Subscription Agreement may be executed and delivered in one or more counterparts (including by facsimile or electronic mail or in
..pdf) and by different parties in separate counterparts, with the same effect as if all parties hereto had signed the same document. All counterparts so executed and delivered shall be construed together and shall constitute one and the same
agreement. 
 (p) This Subscription Agreement shall be governed by, and construed in accordance with, the laws of the State of New York,
without regard to the principles of conflicts of laws that would otherwise require the application of the law of any other state. 

  
 17 

 (q) EACH PARTY AND ANY PERSON ASSERTING RIGHTS AS A THIRD PARTY BENEFICIARY HEREBY
WAIVES ITS RESPECTIVE RIGHTS TO A TRIAL BY JURY OF ANY CLAIM OR CAUSE OF ACTION BASED UPON OR ARISING OUT OR RELATED TO THIS SUBSCRIPTION AGREEMENT OR THE TRANSACTIONS CONTEMPLATED HEREBY IN ANY ACTION, PROCEEDING OR OTHER LITIGATION OF ANY TYPE
BROUGHT BY ANY PARTY AGAINST ANY OTHER PARTY OR ANY AFFILIATE OF ANY OTHER SUCH PARTY, WHETHER WITH RESPECT TO CONTRACT CLAIMS, TORT CLAIMS OR OTHERWISE. THE PARTIES AGREE THAT ANY SUCH CLAIM OR CAUSE OF ACTION SHALL BE TRIED BY A COURT TRIAL
WITHOUT A JURY. WITHOUT LIMITING THE FOREGOING, THE PARTIES FURTHER AGREE THAT THEIR RESPECTIVE RIGHT TO A TRIAL BY JURY IS WAIVED BY OPERATION OF THIS SECTION AS TO ANY ACTION, COUNTERCLAIM OR OTHER PROCEEDING WHICH SEEKS, IN WHOLE OR IN PART, TO
CHALLENGE THE VALIDITY OR ENFORCEABILITY OF THIS SUBSCRIPTION AGREEMENT OR ANY PROVISION HEREOF. THIS WAIVER SHALL APPLY TO ANY SUBSEQUENT AMENDMENTS, RENEWALS, SUPPLEMENTS OR MODIFICATIONS TO THIS SUBSCRIPTION AGREEMENT. 

(r) The parties agree that all disputes, legal actions, suits and proceedings arising out of or relating to this Subscription Agreement must be
brought exclusively in the United States District Court for the Southern District of New York, the Supreme Court of the State of New York and the federal courts of the United States of America located in the State of New York (collectively the
“Designated Courts”). Each party hereby consents and submits to the exclusive jurisdiction of the Designated Courts. No legal action, suit or proceeding with respect to this Subscription Agreement may be brought in any other forum.
Each party hereby irrevocably waives all claims of immunity from jurisdiction, and any objection which such party may now or hereafter have to the laying of venue of any suit, action or proceeding in any Designated Court, including any right to
object on the basis that any dispute, action, suit or proceeding brought in the Designated Courts has been brought in an improper or inconvenient forum or venue. Each of the parties also agrees that delivery of any process, summons, notice or
document to a party hereof in compliance with Section 10(a) of this Subscription Agreement shall be effective service of process for any action, suit or proceeding in a Designated Court with respect to any matters to which
the parties have submitted to jurisdiction as set forth above. 
 (s) This Subscription Agreement may only be enforced against, and any
claim, action, suit or other legal proceeding based upon, arising out of, or related to this Subscription Agreement, or the negotiation, execution or performance of this Subscription Agreement, may only be brought against the entities that are
expressly named as parties or third party beneficiaries hereto and then only with respect to the specific obligations set forth herein with respect to such party or third party beneficiary. No past, present or future director, officer, employee,
incorporator, manager, member, partner, stockholder, affiliate, agent, attorney or other representative of any party hereto or of any affiliate of any party hereto, or any of their successors or permitted assigns, shall have any liability for any
obligations or liabilities of any party hereto under this Subscription Agreement or for any claim, action, suit or other legal proceeding based on, in respect of or by reason of the transactions contemplated hereby. 

(t) Subscriber hereby consents to the publication and disclosure in any press release issued by the Company or IonQ, any Form 8-K filed by the Company with the Commission in connection with the execution and delivery of the Transaction Agreement or the transactions contemplated thereby and the Proxy Statement (as defined in the Transaction
Agreement) (and, as and to the extent otherwise required by the federal securities laws, exchange rules, the 

  
 18 

 
Commission or any other securities authorities or any rules and regulations promulgated thereby, any other documents or communications provided by the Company or IonQ to any governmental entity
or to any securityholders of the Company) of Subscriber’s identity and beneficial ownership of the Subscribed Shares and the nature of Subscriber’s commitments, arrangements and understandings under and relating to this Agreement and, if
deemed appropriate by the Company or IonQ, a copy of this Agreement, all solely to the extent required by applicable law or any regulation or stock exchange listing requirement. Subscriber will promptly provide any information reasonably requested
by the Company or IonQ for any regulatory application or filing made or approval sought in connection with the Transaction (including filings with the Commission). For the avoidance of doubt, nothing in this Agreement shall require or be deemed to
require the Company or IonQ to make public or disclose any material, non-public information that the Company and/or IonQ have provided to Subscriber other than the material,
non-public information that is contained in the Proxy Statement (as defined in the Transaction Agreement) or other filings of the Company with the Commission. Notwithstanding the foregoing, the Company shall
provide to Subscriber a copy of any proposed disclosure relating to the Subscriber in accordance with the provisions of this Section 10(t) in advance of any publication thereof and shall include such revisions to such
proposed disclosure as Subscriber shall reasonably request. 
 (u) The obligations of Subscriber under this Subscription Agreement are
several and not joint with the obligations of any Other Subscriber or any other investor under the Other Subscription Agreements, and Subscriber shall not be responsible in any way for the performance of the obligations of any Other Subscriber under
this Subscription Agreement or any Other Subscriber or other investor under the Other Subscription Agreements. The decision of Subscriber to purchase Subscribed Shares pursuant to this Subscription Agreement has been made by Subscriber independently
of any Other Subscriber or any other investor and independently of any information, materials, statements or opinions as to the business, affairs, operations, assets, properties, liabilities, results of operations, condition (financial or otherwise)
or prospects of the Company, IonQ or any of their respective subsidiaries which may have been made or given by any Other Subscriber or investor or by any agent or employee of any Other Subscriber or investor, and neither Subscriber nor any of its
agents or employees shall have any liability to any Other Subscriber or investor (or any other person) relating to or arising from any such information, materials, statements or opinions. Nothing contained herein or in any Other Subscription
Agreement, and no action taken by Subscriber or investor pursuant hereto or thereto, shall be deemed to constitute Subscriber and Other Subscribers or other investors as a partnership, an association, a joint venture or any other kind of entity, or
create a presumption that Subscriber and Other Subscribers or other investors are in any way acting in concert or as a group with respect to such obligations or the transactions contemplated by this Subscription Agreement and the Other Subscription
Agreements. Subscriber acknowledges that no Other Subscriber has acted as agent for Subscriber in connection with making its investment hereunder and no Other Subscriber will be acting as agent of Subscriber in connection with monitoring its
investment in the Subscribed Shares or enforcing its rights under this Subscription Agreement. Subscriber shall be entitled to independently protect and enforce its rights, including without limitation the rights arising out of this Subscription
Agreement, and it shall not be necessary for any Other Subscriber or investor to be joined as an additional party in any proceeding for such purpose. 

[Signature pages follow.] 

  
 19 

 IN WITNESS WHEREOF, each of the Company and Subscriber has executed or caused this
Subscription Agreement to be executed by its duly authorized representative as of the date first set forth above. 
  

			
	[●]
		
	By:	 	  

 
			
	Name:	 	
	Title	 	
	
	Address for Notices
	
	[●]
	
	ATTN: [●]
	EMAIL:	 	[●]
	
	with a copy (not to constitute notice) to:
	
	[●]
	
	ATTN: [●]
	EMAIL:	 	[●]
	
	Name in which shares are to be registered:

  

					
	 Number of Subscribed Shares subscribed for:
	  			
		  	  
	  
	 
	 Price Per Subscribed Share:
	  	$	10.00	 
	 Aggregate Purchase Price:
	  	$	 	 
		  	  
	  
	 

 You must pay the Purchase Price by wire transfer of United States dollars in immediately available funds to the account of the
Company specified by the Company in the Closing Notice 

  
 [Signature Page to
Subscription Agreement] 

 
			
	DMY TECHNOLOGY GROUP, INC. III
		
	By:	 	  

 
			
	Name:	 	
	Title	 	
	
	Address for Notices
		
	[●]	 	
	
	ATTN: Niccolo de Masi, Chief Executive Officer
	EMAIL: niccolo@dmytechnology.com
	
	with a copy (not to constitute notice) to:
	
	CLEARY GOTTLIEB STEEN & HAMILTON LLP
	ONE LIBERTY PLAZA, NEW YORK NY 10006
		
	ATTN:	 	Giovanni P. Prezioso
	 Adam J. Brenneman

	
	EMAIL: gprezioso@cgsh.com
	 abrenneman@cgsh.com

  
 [Signature Page to
Subscription Agreement] 

 ANNEX A 

ELIGIBILITY REPRESENTATIONS OF SUBSCRIBER 

This Annex A should be completed and signed by Subscriber 

and constitutes a part of the Subscription Agreement. 
  

	A.	 QUALIFIED INSTITUTIONAL BUYER STATUS (Please check the box, if applicable) 

 

	 	☐	 Subscriber is a “qualified institutional buyer” (as defined in Rule 144A under the Securities Act).

  

	B.	 ACCREDITED INVESTOR STATUS (Please check the box) 

 

	 	☐	 Subscriber is an “accredited investor” (within the meaning of Rule 501(a)(1), (2), (3), (5), (6), (7)
or (8) under the Securities Act) and has marked and initialed the appropriate box below indicating the provision under which it qualifies as an “accredited investor.” 

 

	C.	 AFFILIATE STATUS (Please check the applicable box) 

SUBSCRIBER: 
  

	 	☐	 is: 

  

	 	☐	 is not: 

an “affiliate” (as defined in Rule 144 under the Securities Act) of the Company or acting on behalf of an affiliate of the Company.

 Rule 501(a), in relevant part, states that an “accredited investor” shall mean any person who comes within any of the below
listed categories, or who the issuer reasonably believes comes within any of the below listed categories, at the time of the sale of the securities to that person. Subscriber has indicated, by marking and initialing the appropriate box below, the
provision(s) below which apply to Subscriber and under which Subscriber accordingly qualifies as an “accredited investor.” 
  

	 	☐	 Any bank, registered broker or dealer, insurance company, registered investment company, business development
company, or small business investment company; 

  

	 	☐	 Any plan established and maintained by a state, its political subdivisions, or any agency or instrumentality of
a state or its political subdivisions for the benefit of its employees, if such plan has total assets in excess of $5,000,000; 

  

	 	☐	 Any employee benefit plan, within the meaning of the Employee Retirement Income Security Act of 1974, if a
bank, insurance company, or registered investment adviser makes the investment decisions, or if the plan has total assets in excess of $5,000,000; 

  

	 	☐	 Any corporation, similar business trust, partnership or any organization described in Section 501(c)(3) of
the Internal Revenue Code, not formed for the specific purpose of acquiring the securities offered, with total assets in excess of $5,000,000; 

	 	☐	 Any natural person whose individual net worth, or joint net worth with that person’s spouse or spousal
equivalent, exceeds $1,000,000; provided, however, that the following will be excluded when calculating a person’s net worth: (1) the person’s primary residence shall not be included as an asset; (2) indebtedness that is
secured by the person’s primary residence, up to the estimated fair market value of the primary residence at the time of the sale of securities, shall not be included as a liability (except that if the amount of such indebtedness outstanding at
the time of sale the Subscribed Shares exceeds the amount outstanding 60 days before such time, other than as a result of the acquisition of the primary residence, the amount of such excess shall be included as a liability); and
(3) indebtedness that is secured by the person’s primary residence in excess of the estimated fair market value of the primary residence at the time of the sale of the Subscribed Shares shall be included as a liability;

  

	 	☐	 Any natural person who had an individual income in excess of $200,000 in each of the two most recent years or
joint income with that person’s spouse or spousal equivalent in excess of $300,000 in each of those years and has a reasonable expectation of reaching the same income level in the current year; 

 

	 	☐	 Any trust with assets in excess of $5,000,000, not formed to acquire the securities offered, whose purchase is
directed by a sophisticated person; or 

  

	 	☐	 Any entity in which all of the equity owners are accredited investors. 

D. FINANCIAL DUE DILIGENCE (Applicable to “natural persons” only) 

Rule 506(c)(ii) requires that an issuer take reasonable steps to verify that purchasers of the Subscribed Shares are accredited investors. An
issuer shall be deemed to take reasonable steps to verify if the issuer uses one of the following non-exclusive methods. Please check the applicable box indicating what form of verification is being provided
by Subscriber. 
  

	 	☐	 Any Internal Revenue Service form that reports Subscriber’s income for the two most recent years
(including, but not limited to, Form W-2, Form 1099, Schedule K-1 to Form 1065, and Form 1040) and a written representation from Subscriber that he or she has a
reasonable expectation of reaching the income level necessary to qualify as an accredited investor during the current year; 

  

	 	☐	 One or more of the following types of documentation dated within the prior three months: (1) with respect
to assets, bank statements, brokerage statements and other statements of securities holdings, certificates of deposit, tax assessments, and appraisal reports issued by independent third parties; and (2) with respect to liabilities, a consumer
report from at least one of the nationwide consumer reporting agencies, and a written representation from Subscriber that all liabilities necessary to make a determination of net worth have been disclosed; or 

 

	 	☐	 A written confirmation from (1) a registered broker-dealer, (2) an investment adviser registered with
the Commission, (3) a licensed attorney who is in good standing under the laws of the jurisdictions in which he or she is admitted to practice law or (4) a certified public accountant who is duly registered and in good standing under the
laws of the place of his or her residence or principal office that such person or entity has taken reasonable steps to verify that Subscriber is an accredited investor within the prior three months and has determined that such Subscriber is an
accredited investor. 

 
			
	SUBSCRIBER:
	Print Name:
		
	By:	 	              

		 	Name:
		 	TitleEX-10.8

 Exhibit 10.8 

Execution Version 
 SPONSOR
SUPPORT AGREEMENT 
 This Sponsor Support Agreement (this “Agreement”) is dated as of March 7, 2021, by
and among dMY Technology Group, Inc. III, a Delaware corporation (“dMY”), dMY Sponsor III, LLC, a Delaware limited liability company (the “Sponsor”), each of the undersigned individuals, each of whom
is a member of dMY’s board of directors and/or management team (each, an “Insider” and collectively, the “Insiders” and together with the Sponsor, the “dMY Holders”) and
IonQ, Inc., a Delaware corporation (the “Company”). Capitalized terms used but not defined herein shall have the respective meanings ascribed to such terms in the Merger Agreement (defined below). 

RECITALS 
 WHEREAS, as of
the date hereof, each dMY Holder is the holder of record and the “beneficial owner” (within the meaning of Rule 13d-3 under the Exchange Act) of certain shares of dMY Class A Common Stock, par
value $0.0001 per share (“dMY Class A Common Stock”), dMY Class B Common Stock, par value $0.0001 per share (“dMY Class B Common
Stock” and together with the dMY Class A Common Stock, “dMY Common Stock”), and warrants exercisable for shares of dMY Class A Common Stock (the “dMY Warrants”) in each case as
set forth on Schedule I attached hereto (all such securities or other equity securities, together with any shares of the dMY’s capital stock or other equity securities of which ownership of record or the power to vote (including, without
limitation, by proxy or power of attorney) is hereafter acquired by any such dMY Holder during the period from the date hereof through the Expiration Time are referred to herein as the “Subject Securities”); 

WHEREAS, contemporaneously with the execution and delivery of this Agreement, dMY, Ion Trap Acquisition Inc., a Delaware corporation and the
Company, have entered into an Agreement and Plan of Merger (as amended or modified from time to time, the “Merger Agreement”), dated as of the date hereof, pursuant to which, among other transactions, Merger Sub will be
merged with and into the Company (the “Merger”), with the Company continuing on as the surviving entity (the “Surviving Corporation”); and each share of Company Preferred Stock will be converted into
Company Common Stock in accordance with the Merger Agreement and each share of Company Common Stock that is issued in respect thereof or otherwise issued and outstanding immediately prior to the Effective Time, shall be canceled and converted into
the right to receive the number of shares of dMY Class A Common Stock described in the Merger Agreement (such transaction, the Merger and the other transactions contemplated by the Merger Agreement, the “Transactions”);

 WHEREAS, Article 4.3(b) of dMY’s Amended and Restated Certificate of Incorporation (the “dMY
Charter”) provides that, automatically on the closing of a Business Combination (as defined in the dMY Charter), each share of dMY Class B Common Stock will automatically convert on a one-for-one basis into shares of dMY Class A Common Stock; provided that, if, in connection with the consummation of a Business Combination, additional shares of dMY Class A Common Stock are issued
or deemed issued in excess of the amounts sold in dMY’s initial public offering, the ratio for which the shares of dMY Class B Common Stock shall convert into shares of dMY Class A Common Stock will be adjusted so that the number of
shares of dMY 

 
Class A Common Stock issuable upon conversion of all shares of dMY Class B Common Stock will equal, in the aggregate, 25% of the sum of (a) the total number of all shares of dMY
Class A Common Stock issued in dMY’s initial public offering (including any shares of dMY Class A Common Stock issued pursuant to the underwriters’ over-allotment option) plus (b) the sum of (i) all shares of dMY
Class A Common Stock issued or deemed issued or issuable upon conversion or exercise of any equity-linked securities or rights issued or deemed issued in connection with or in relation to the consummation of the Business Combination (including
any shares of dMY Class A Common Stock issued pursuant to a forward purchase agreement), excluding any shares of dMY Class A Common Stock or equity-linked securities or rights issued, or to be issued, to any seller in the Business
Combination, any private placement warrants issued to the Sponsor, or an affiliate of the Sponsor or dMY’s officers and directors upon the conversion of working capital loans made to dMY and any warrants issued pursuant to a forward purchase
agreement, minus (ii) the number of shares of dMY Class A Common Stock redeemed in connection with a Business Combination, provided that such conversion of shares of dMY Class B Common Stock shall never be less than on a one-for-one basis (the “Conversion Rights Provision”); 

WHEREAS, under the dMY Charter, the Transactions (including the PIPE Investment) will trigger the Conversion Rights Provision; and 

WHEREAS, in connection with the Transactions, the parties hereto desire that each dMY Holder irrevocably waives his, her or its rights under
Article 4.3(b) of the dMY Charter with respect to any additional shares of dMY Class A Common Stock otherwise issuable upon conversion pursuant to the Conversion Rights Provision (the “Excess Shares”). 

WHEREAS, as an inducement to dMY and the Company to enter into the Merger Agreement and to consummate the transactions contemplated therein,
the parties hereto desire to agree to certain matters as set forth herein. 
 AGREEMENT 

NOW, THEREFORE, in consideration of the foregoing, in order to induce the Company and dMY to enter into the Merger Agreement and for other
good and valuable consideration, the receipt and sufficiency of which are hereby acknowledged, the parties hereto agree, as follows: 

ARTICLE I 
 SPONSOR
SUPPORT AGREEMENT; COVENANTS 
 Section 1.1 Binding Effect of Merger Agreement. Each dMY Holder hereby
acknowledges that it has read the Merger Agreement and this Agreement and has had the opportunity to consult with its tax and legal advisors. During the period commencing on the date hereof and ending on the earlier to occur of (a) the
Effective Time and (b) such date and time as the Merger Agreement shall be terminated in accordance with Section 7.1 thereof (the “Expiration Time”), each dMY Holder shall be bound by and comply with
Section 6.9 (Communications; Press Releases) (other than the first clause of the first sentence of Section 6.9), Section 8.10 (Trust Account Waiver) and Section 8.14 (No Recourse) of the Merger Agreement (and any relevant
definitions contained in such Section) as if (a) the Sponsor or such Insider was an original signatory to the Merger Agreement with respect to such provision and (b) each reference to dMY contained in such provisions also referred to such
dMY Holder. 

  
 2 

 Section 1.2 Competing Transaction. From the date hereof until the Expiration
Time, each dMY Holder shall not, and shall cause its controlled Affiliates and instruct its Related Parties, not to, directly or indirectly, (i) solicit or take any action to facilitate or encourage any inquiries or the making, submission or
announcement of, any proposal or offer from any Alternative Target or its Representatives that may constitute, or would reasonably be expected to lead to, a dMY Competing Transaction; (ii) enter into, participate in, continue or otherwise
engage in, any discussions or negotiations with any Alternative Target regarding a dMY Competing Transaction; (iii) furnish (including through the Data Room) any information relating to dMY or any of its assets or businesses, or afford access
to the assets, business, properties, books or records of dMY to an Alternative Target, in all cases for the purpose of assisting with or facilitating, or that would otherwise reasonably be expected to lead to, a dMY Competing Transaction;
(iv) approve, endorse or recommend any dMY Competing Transaction; or (v) enter into any dMY Competing Transaction or any agreement, arrangement or understanding (including any letter of intent or term sheet) relating to a dMY Competing
Transaction or publicly announce an intention to take any such actions. Each dMY Holder shall, and shall instruct its Related Parties to, immediately cease any and all existing discussions or negotiations with any Person conducted prior to the date
hereof with respect to, or which is reasonably likely to give rise to or result in, a dMY Competing Transaction. 
 Section 1.3 No
Transfer. From the date hereof until the Expiration Time, no dMY Holder shall, (i) sell, offer to sell, contract or agree to sell, hypothecate, pledge, grant any option to purchase or otherwise dispose of or agree to dispose of, directly or
indirectly, file (or participate in the filing of) a registration statement with the SEC (other than the Registration Statement) or establish or increase a put equivalent position or liquidate or decrease a call equivalent position within the
meaning of Section 16 of the Exchange Act, with respect to any Subject Securities, (ii) deposit any Subject Securities into a voting trust or enter into a voting agreement or arrangement or grant any proxy or power of attorney with respect
thereto that is inconsistent with this Agreement, or (iii) enter into any swap or other arrangement that transfers to another, in whole or in part, any of the economic consequences of ownership of any Subject Shares, (clauses (i), (ii) and
(iii), collectively, a “Transfer”), except, in each case, for any Transfers of Subject Securities from a dMY Holder (x) who is an entity, (A) to any partner, member or Affiliate thereof or (B) to dMY’s
officers or directors, any affiliate or family member of any of dMY’s officers or directors, any affiliate of the Sponsor or to any members of the Sponsor or any of their affiliates and (y) who is an individual, (A) to any member of
such dMY Holder’s immediate family, or to a trust for the benefit of such dMY Holder or any member of the immediate family of such dMY Holder, the sole trustees of which are such dMY Holder or any member of such dMY Holder’s immediate
family, an affiliate of such dMY Holder or to a charitable organization, (B) by will, other testamentary document or under the Laws of intestacy upon the death of such dMY Holder or (C) pursuant to a qualified domestic relations order (a
“Permitted Transfer”); provided, however, that any Permitted Transfer shall be permitted only if, as a precondition to such Transfer, the transferee also agrees in a writing, reasonably satisfactory in form and substance to
the Company, to assume all of the obligations of such dMY Holder under, and be bound by all of the terms of, this Agreement; provided, further, that any Transfer permitted under this Section 1.3 shall not relieve such dMY Holder of its
obligations under this Agreement. Any Transfer in violation of this Section 1.3 with respect to the Subject Securities of any dMY Holder shall be void ab initio and of no force or effect. 

  
 3 

 Section 1.4 New Shares. In the event that, during the period commencing on the
date hereof and ending at the Expiration Time, (a) any Subject Securities are issued to any dMY Holder after the date of this Agreement pursuant to any stock dividend, stock split, recapitalization, reclassification, combination or exchange of
Subject Securities or otherwise, (b) any dMY Holder purchases or otherwise acquires beneficial ownership of any Subject Securities or (c) any dMY Holder acquires the right to vote or share in the voting of any Subject Securities
(collectively the “New Securities”), then such New Securities acquired or purchased by such dMY Holder shall be subject to the terms of this Agreement to the same extent as if they constituted the Subject Securities owned by
such dMY Holder as of the date hereof. 
 Section 1.5 Sponsor Agreements. 

(a) Hereafter until the Expiration Time, at any meeting of the dMY Stockholders of dMY (or any adjournment or postponement thereof), or in any
other circumstance in which the vote, consent or other approval of the dMY Stockholders is sought, each dMY Holder shall (i) appear at each such meeting or otherwise cause all of its Subject Securities that are shares of dMY Common Stock that
are entitled to vote on such matters (“dMY Voting Shares”) to be counted as present thereat for purposes of calculating a quorum and (ii) vote (or cause to be voted), or execute and deliver a written consent (or cause a
written consent to be executed and delivered) covering, all of its, his, or her dMY Voting Shares: 
 (i) in favor of each dMY Stockholder
Voting Matter, including the approval and adoption of the Merger Agreement and the Transactions; 
 (ii) against and withhold consent with
respect to any dMY Competing Transaction; 
 (iii) against any business combination agreement or merger (other than the Merger Agreement and
the Transactions), consolidation, combination, sale of substantial assets, reorganization, recapitalization, dissolution, liquidation or winding up of or by dMY; 

(iv) against any proposal, action or agreement that would (A) materially impede, frustrate, prevent or nullify any provision of this
Agreement, the Merger Agreement or the Transactions, (B) result in a breach in any respect of any covenant, representation, warranty or any other obligation or agreement of dMY under the Merger Agreement or (C) result in any of the
conditions set forth in Sections 2.4 or 2.6 of the Merger Agreement not being fulfilled. 
 (b) Hereafter until the Expiration Time, each
dMY Holder hereby unconditionally and irrevocably agrees that such dMY Holder, as applicable, shall: 
 (i) not commit or agree to take any
action inconsistent with the foregoing covenants set forth in Section 1.5(a); and 

  
 4 

 (ii) not redeem any shares of dMY Common Stock owned by such dMY Holder in connection with
such stockholder approval or proposed the dMY Stockholder Voting Matters. 
 Section 1.6 Waiver of Conversion Ratio Adjustment.

 (a) As of and conditioned upon the Closing, each dMY Holder hereby irrevocably relinquishes and waives any and all rights such dMY Holder
has or will have under Section 4.3(b)(ii) of dMY Charter to receive any Excess Shares upon conversion of any of the dMY Class B Common Stock held by him, her or it, as applicable, in connection with the Closing. 

(b) Each dMY Holder hereby acknowledges and agrees that, to the extent such dMY Holder receives any Excess Shares as a result of any
conversion of shares of dMY Class B Common Stock, such dMY Holder shall surrender such shares, including any certificates thereof, to dMY for cancellation, and no consideration shall be payable to such dMY Holder in connection therewith. 

(c) Each dMY Holder hereby acknowledges and agrees that, immediately prior to the Effective Time, and subject to Section 1.7(a), each
share of dMY Class B Common Stock that is issued and outstanding as of such time shall automatically convert in accordance with the Conversion Rights Provision into one share of dMY Class A Common Stock, and each dMY Holder jointly and
severally agree that as a result of such conversion, all outstanding shares of dMY Class B Common Stock shall collectively convert into 7,500,000 shares of dMY Class A Common Stock (subject to the vesting provisions set forth in Article II
and ordinary equitable adjustments on account of any share split, reverse share split or similar equity restructuring transaction). 

Section 1.7 Closing Date Deliverables. On the Closing Date, each dMY Holder that holds any Subject Securities shall deliver to dMY
and the Company a duly executed copy of the Investor Rights Agreement substantially in the form attached as Exhibit C to the Merger Agreement. 

Section 1.8 Consent to Disclosure. Each dMY Holder hereby consents to the publication and disclosure in the Registration Statement
(and, as and to the extent otherwise required by applicable securities Laws or the SEC or any other securities authorities, any other documents or communications provided by the Company or dMY to any Governmental Entity or to securityholders of dMY)
of the identity of the Sponsor or such Insider, as applicable, and beneficial ownership of Subject Securities and the nature of such Company Stockholder’s commitments, arrangements and understandings under and relating to this Agreement and, if
deemed appropriate by the Company or dMY, a copy of this Agreement. 
 ARTICLE II 

VESTING PROVISIONS 

Section 2.1 Vesting Provisions for Founder Shares. The Sponsor and each of the Insiders agrees that, effective upon the Closing,
the number of shares of dMY Common Stock set forth beside each such Person’s name on Exhibit A hereto (which represent, in the aggregate, 750,000 shares of dMY Common Stock, the “Founder Shares”) shall be unvested and
shall be 

  
 5 

 
subject to the vesting and forfeiture provisions set forth in this Article II (the “Vesting Shares”). In addition to, and without limiting, any restrictions on Transfers
set forth in that certain Letter Agreement, dated as of October 28, 2020, by and among dMY, the dMY Holders and the other parties thereto (the “IPO Letter Agreement”), each dMY Holder agrees that it shall not (and will
cause its Affiliates not to) Transfer any unvested Vesting Shares prior to the date such Vesting Shares become vested pursuant to this Article II. Each dMY Holder agrees that, in connection with the Transactions, the Vesting Shares shall,
concurrently with the Closing, have the following legend affixed to them as set forth in this Section 2.1. The books and records of dMY evidencing the Vesting Shares shall be stamped or otherwise imprinted with a legend in substantially the
following form: 
 THE SECURITIES EVIDENCED HEREIN ARE SUBJECT TO RESTRICTIONS ON TRANSFER, AND CERTAIN OTHER AGREEMENTS, SET FORTH IN THE
SPONSOR SUPPORT AGREEMENT DATED AS OF MARCH 7, 2021, BY AND AMONG DMY TECHNOLOGY GROUP, INC. III AND THE OTHER PARTIES THERETO. 

Section 2.2 Vesting of Shares. 

(a) Each dMY Holder acknowledged and agrees that the Vesting Shares shall be subject to vesting from and after the Closing through and until
the date that is five years after the Closing Date (the “Sponsor Vesting Period”): 
 (i) One third of the Vesting
Shares beneficially owned by the dMY Holders shall vest and be released from escrow, in proportion to their ownership of the Vesting Shares, if at any time during Sponsor Vesting Period: (x) the closing price of dMY Common Stock equals or
exceeds $12.50 for any 20 Trading Days during any period of 30 consecutive Trading Days or (y) dMY consummates a Subsequent Transaction which results in its stockholders having the right to exchange their shares for cash, securities or other
property having a value of at least $12.50 per share; 
 (ii) One third of the Vesting Shares beneficially owned by the dMY Holder shall
vest and be released from escrow, in proportion to their ownership of the Vesting Shares, if at any time during the Sponsor Vesting Period: (x) the closing price of dMY Common Stock equals or exceeds $15.00 for any 20 Trading Days during any
period of 30 consecutive Trading Days or (y) dMY consummates a Subsequent Transaction which results in its stockholders having the right to exchange their shares for cash, securities or other property having a value of at least $15.00 per
share; and 
 (iii) One third of the Vesting Shares beneficially owned by Sponsor and each of the Insiders shall vest and be released from
escrow, in proportion to their ownership of the Vesting Shares, if at any time during the Sponsor Vesting Period (x) the closing price of dMY Common Stock equals or exceeds $17.50 for any 20 Trading Days during any period of 30 consecutive
Trading Days or (y) dMY consummates a Subsequent Transaction which results in its stockholders having the right to exchange their shares for cash, securities or other property having a value of at least $17.50 per share. 

  
 6 

 (b) Forfeiture of Unvested Founder Shares. Vesting Shares that remain unvested on
the first Business Day after the conclusion of the Sponsor Vesting Period shall be surrendered by the dMY Holders to dMY, without any consideration for such Transfer. 

(c) Stock Price Level. The closing price of dMY Common Stock and the per share consideration with respect to any Subsequent Transaction
shall be equitably adjusted on account of any share split, reverse share split or similar equity restructuring transaction. 
 (d)
Certain Definitions. For purposes of this Article II, the following terms shall have the following meanings: 
 (i)
“Subsequent Transaction” shall mean the occurrence of any of the following events: (i) any Person or any group of Persons acting together which would constitute a “group” for purposes of Section 13(d) of
the Exchange Act or any successor provisions thereto is or becomes the beneficial owner, directly or indirectly, of securities of dMY representing more than 50% of the combined voting power of dMY’s then outstanding voting securities,
(ii) there is consummated a merger or consolidation of dMY with any other corporation or other entity, and, immediately after the consummation of such merger or consolidation, the voting securities of dMY immediately prior to such merger or
consolidation do not continue to represent or are not converted into more than 50% of the combined voting power of the then outstanding voting securities of the Person resulting from such merger or consolidation or, if the surviving company is a
Subsidiary, the ultimate parent thereof, or (iii) the shareholders of dMY approve a plan of complete liquidation or dissolution of dMY or there is consummated an agreement or series of related agreements for the sale, lease or other
disposition, directly or indirectly, by dMY of all or substantially all of the assets of dMY and its Subsidiaries, taken as a whole, other than such sale or other disposition by dMY of all or substantially all of the assets of dMY and its
Subsidiaries, taken as a whole, to an entity at least 50% of the combined voting power of the voting securities of which are owned by shareholders of dMY in substantially the same proportions as their ownership of dMY immediately prior to such sale.

 (ii) “Trading Day” means any day on which shares of dMY Common Stock are actually traded on the Trading Market.

 (iii) “Trading Market” means the New York Stock Exchange or any other stock market on which shares of dMY Common
Stock shall be trading at the time of determination of the the closing price of such shares. 
 ARTICLE III 

REPRESENTATIONS AND WARRANTIES 

Each dMY Holder represents and warrants as of the date hereof (or the date such dMY Holder becomes a party hereto) to dMY and the Company
(solely with respect to such dMY Holder and not with respect to any other dMY Holder) as follows: 
 Section 3.1 Organization; Due
Authorization. If such dMY Holder is not a natural person, such dMY Holder is duly organized, validly existing and in good standing under the Laws of the jurisdiction in which it is incorporated, formed, organized or constituted, and the
execution, delivery and performance of this Agreement and the consummation of the transactions 

  
 7 

 
contemplated hereby are within such dMY Holder’s corporate, limited liability company or organizational powers and have been duly authorized by all necessary corporate, limited liability
company or organizational actions on the part of such dMY Holder. If such dMY Holder is an individual, such dMY Holder has full legal capacity, right and authority to execute and deliver this Agreement and to perform his or her obligations
hereunder. This Agreement has been duly executed and delivered by such dMY Holder and, assuming due authorization, execution and delivery by the other parties to this Agreement, this Agreement constitutes a legally valid and binding obligation of
such dMY Holder, enforceable against such dMY Holder in accordance with the terms hereof (subject to the Remedies Exception). If this Agreement is being executed in a representative or fiduciary capacity, the Person signing this Agreement has full
power and authority to enter into this Agreement on behalf of such dMY Holder. 
 Section 3.2 Ownership. Such dMY Holder is the
record and beneficial owner (as defined in the Securities Act) of, and has good title to, all of the Subject Securities listed across from such dMY Holder’s name on Schedule 1 hereto, and there exist no Liens or any other limitation or
restriction (including any restriction on the right to vote, sell or otherwise dispose of such Subject Securities (other than transfer restrictions under the Securities Act)) affecting any such Subject Securities, other than Liens pursuant to
(i) this Agreement, (ii) the dMY Governing Documents, (iii) the Merger Agreement, (iv) the IPO Letter Agreement or (v) any applicable securities Laws. The Subject Securities are the only equity securities in dMY owned of
record or beneficially by such dMY Holder on the date of this Agreement, and none of the Subject Securities held by such dMY Holder are subject to any proxy, voting trust or other agreement or arrangement with respect to the voting of such Subject
Securities, except as provided hereunder and under the IPO Letter Agreement. Such dMY Holder has full voting power with respect to the Subject Securities held by such dMY Holder. Other than the Subject Securities held by such dMY Holder, such dMY
Holder does not hold or own any rights to acquire (directly or indirectly) any equity securities of dMY or any equity securities convertible into, or which can be exchanged for equity securities of dMY. 

Section 3.3 No Conflicts. The execution and delivery of this Agreement by such dMY Holder does not, and the performance by such
dMY Holder of its obligations hereunder will not, (i) conflict with or result in a violation of the organizational documents of such dMY Holder, (ii) require any consent or approval that has not been given or other action that has not been
taken by any Person (including under any contract binding upon such dMY Holder or such dMY Holder’s Subject Securities), in each case, to the extent such consent, approval or other action would prevent, enjoin or materially delay the
performance by such dMY Holder of its obligations under this Agreement or (iii) conflict with or violate any Law. 
 Section 3.4
Litigation. Except as set forth on Section 4.7 of the dMY Disclosure Letter to the Merger Agreement, there are no Proceedings pending against such dMY Holder, or to the knowledge of such dMY Holder threatened against such dMY Holder,
before (or, in the case of threatened Proceedings, that would be before) any arbitrator or any Governmental Entity, which in any manner challenges or seeks to prevent, enjoin or materially delay the performance by such dMY Holder of its obligations
under this Agreement. 

  
 8 

 Section 3.5 Brokerage Fees. Except as described on Section 4.3 of
dMY’s Disclosure Letter to the Merger Agreement, no broker, finder, investment banker or other Person is entitled to any brokerage fee, finders’ fee or other commission in connection with the Transactions or the dMY IPO based upon
arrangements made by such dMY Holder, for which dMY or any of its Affiliates (including, from and after the Closing, the Company) may become liable. 

Section 3.6 Acknowledgment. Such dMY Holder understands and acknowledges that each of dMY and the Company is entering into the
Merger Agreement in reliance upon such dMY Holder’s execution and delivery of this Agreement. 
 ARTICLE IV 

MISCELLANEOUS 

Section 4.1 Termination. 

(a) This Agreement and all of its provisions (other than those provisions which expressly survive the Closing, as set forth in Article II and
this Article IV, collectively, the “Surviving Provisions”) shall terminate and be of no further force or effect upon the earliest of (i) the Expiration Time, and (ii) the written agreement of the Sponsor, dMY, and
the Company. 
 (b) If the Closing occurs, then the Surviving Provisions shall continue in force until the first to occur of (i) the
vesting of all of the Vesting Shares in accordance with this Agreement, (ii) the termination of the Sponsor Vesting Period and (iii) the written agreement of the Sponsor, dMY, and the Company; provided, that the provisions set forth in
this Article IV shall survive any such termination. 
 (c) Upon any termination of this Agreement in the entirety, all obligations of the
parties under this Agreement will terminate, without any liability or other obligation on the part of any party hereto to any Person in respect hereof or the transactions contemplated hereby, and no party hereto shall have any claim against another
(and no person shall have any rights against such party), whether under contract, tort or otherwise, with respect to the subject matter hereof; provided, however, that the termination of this Agreement shall not relieve any party hereto from
liability arising in respect of any breach of this Agreement prior to such termination. 
 (d) Notwithstanding anything to the foregoing,
this Article IV shall survive the termination of this Agreement. 
 Section 4.2 Governing Law. The Law of the State of Delaware
shall govern (a) all claims or matters related to or arising from this Agreement (including any tort or non-contractual claims) and (b) any questions concerning the construction, interpretation,
validity and enforceability of this Agreement, and the performance of the obligations imposed by this Agreement, in each case without giving effect to any choice of law or conflict of law rules or provisions (whether of the State of Delaware or any
other jurisdiction) that would cause the application of the Law of any jurisdiction other than the State of Delaware. 

  
 9 

 Section 4.3 CONSENT TO JURISDICTION AND SERVICE OF PROCESS; WAIVER OF JURY
TRIAL. 
 (a) Each party hereto submits to the exclusive jurisdiction of first, the Court of Chancery of the State of Delaware or if
such court declines jurisdiction, then to any court of the State of Delaware or the Federal District Court for the District of Delaware, in any Proceeding arising out of or relating to this Agreement, agrees that all claims in respect of the
Proceeding shall be heard and determined in any such court and agrees not to bring any Proceeding arising out of or relating to this Agreement in any other courts. Nothing in this Section 4.3, however, shall affect the right of any party to
serve legal process in any other manner permitted by Law or at equity. Each party hereto agrees that a final judgment in any Proceeding so brought shall be conclusive and may be enforced by suit on the judgment or in any other manner provided by Law
or at equity. 
 (b) WAIVER OF TRIAL BY JURY. EACH PARTY HERETO HEREBY IRREVOCABLY WAIVES ALL RIGHTS TO TRIAL BY JURY IN ANY PROCEEDING
BROUGHT TO RESOLVE ANY DISPUTE BETWEEN OR AMONG ANY OF THE PARTIES (WHETHER ARISING IN CONTRACT, TORT OR OTHERWISE) ARISING OUT OF, CONNECTED WITH, RELATED OR INCIDENTAL TO THIS AGREEMENT, THE TRANSACTIONS OR THE RELATIONSHIPS ESTABLISHED AMONG THE
PARTIES UNDER THIS AGREEMENT. EACH PARTY FURTHER WARRANTS AND REPRESENTS THAT SUCH PARTY HAS REVIEWED THIS WAIVER WITH ITS LEGAL COUNSEL, AND THAT SUCH PARTY KNOWINGLY AND VOLUNTARILY WAIVES ITS JURY TRIAL RIGHTS FOLLOWING CONSULTATION WITH LEGAL
COUNSEL. 
 Section 4.4 Assignment. This Agreement and all of the provisions hereof will be binding upon and inure to the
benefit of the parties hereto and their respective heirs, successors and permitted assigns. Neither this Agreement nor any of the rights, interests or obligations hereunder will be assigned (including by operation of law) without the prior written
consent of the parties hereto. Any purported assignment or delegation not permitted under this Section 4.4 shall be null and void. 

Section 4.5 Specific Performance. The parties hereto agree that irreparable damage would occur in the event any provision of this
Agreement was not performed in accordance with the terms hereof and that the parties shall be entitled to specific performance of the terms hereof, in addition to any other remedy at law or in equity without the necessity of proving the inadequacy
of money damages as a remedy and without bond or other security being required, this being in addition to any other remedy to which they are entitled at law or in equity. Each of the parties hereto hereby further acknowledges that the existence of
any other remedy contemplated by this Agreement does not diminish the availability of specific performance of the obligations hereunder or any other injunctive relief. It is accordingly agreed that the parties hereto shall be entitled to seek an
injunction or injunctions to prevent breaches of this Agreement and to enforce specifically the terms and provisions of this Agreement in the chancery court or any other state or federal court within the State of Delaware, this being in addition to
any other remedy to 

  
 10 

 
which such party is entitled at law or in equity. Each party hereto hereby further agrees that in the event of any action by any other party for specific performance or injunctive relief, it will
not assert that a remedy at law or other remedy would be adequate or that specific performance or injunctive relief in respect of such breach or violation should not be available on the grounds that money damages are adequate or any other grounds.

 Section 4.6 Amendment, Waiver. This Agreement may not be amended, changed, supplemented, waived or otherwise modified or
terminated (other than to correct a typographical error) as to any particular provision, except by a written instrument executed by all parties hereto. 

Section 4.7 Severability. Whenever possible, each provision of this Agreement shall be interpreted in such manner as to be
effective and valid under applicable Law, but if any provision of this Agreement or the application of any such provision to any Person or circumstance shall be held to be prohibited by or invalid, illegal or unenforceable under applicable Law in
any respect by a court of competent jurisdiction, such provision shall be ineffective only to the extent of such prohibition or invalidity, illegality or unenforceability, without invalidating the remainder of such provision or the remaining
provisions of this Agreement. Furthermore, in lieu of such illegal, invalid or unenforceable provision, there shall be added automatically as a part of this Agreement a legal, valid and enforceable provision as similar in terms to such illegal,
invalid, or unenforceable provision as may be possible. 
 Section 4.8 Notices. All notices, demands and other communications to
be given or delivered under this Agreement shall be in writing and shall be deemed to have been given (a) when personally delivered (or, if delivery is refused, upon presentment) or received by email prior to 6:00 p.m. eastern time on a
Business Day and, if otherwise, on the next Business Day, (b) one (1) Business Day following sending by reputable overnight express courier (charges prepaid) or (c) three (3) days following mailing by certified or registered mail,
postage prepaid and return receipt requested. Unless another address is specified in writing pursuant to the provisions of this Section 4.8, notices, demands and other communications to the Parties shall be sent to the addresses indicated
below: 
 If to dMY: 

dMY Technology Group, Inc. III 

1180 North Town Center Drive, Suite 100 

Las Vegas, Nevada 89144 

Attention:     Niccolo de Masi 

                     Harry L. You 

Email:           niccolo@dmytechnology.com 

                     
harry@dmytechnology.com 
 with a copy to (which will not constitute notice): 

Cleary Gottlieb Steen & Hamilton LLP 

One Liberty Plaza 
 New York NY
10006 

  
 11 

 Attention:     Kyle A. Harris 

                     James E. Langston

 E-mail:         kaharris@cgsh.com 

                     
jlangston@cgsh.com 
 If to the Company: 

IonQ, Inc. 
 4505 Campus Dr. 

College Park, MD 20740 

Attention:     Peter Chapman, CEO; Legal Department 

E-mail:         chapman@ionq.co; legal@ionq.co 

with a copy to (which shall not constitute notice): 

Cooley LLP 
 55 Hudson Yards 

New York, New York 10001-2157 

Attention:     David Silverman 

                     John McKenna 

Email:          dsilverman@cooley.com 

                     jmckenna@cooley.com

 If to a dMY Holder: 

To such dMY Holder’s address set forth in Schedule I 

with a copy to (which will not constitute notice): 

Cleary Gottlieb Steen & Hamilton LLP 

One Liberty Plaza 
 New York NY
10006 
 Attention:     Kyle A. Harris 

                     James E. Langston

 E-mail:         kaharris@cgsh.com 

                     
jlangston@cgsh.com 
 Section 4.9 Capacity. Each dMY Holder is signing this Agreement solely in such dMY Holder’s capacity
as a holder of Subject Securities, and not in such dMY Holder’s capacity as a director, officer or employee of dMY or in such dMY Holder’s capacity as a trustee or fiduciary of any employee benefit plan or trust. Notwithstanding anything
herein to the contrary, nothing herein shall in any way restrict a director or officer of dMY in the exercise of his or her fiduciary duties as a director or officer of dMY or in his or her capacity as a trustee or fiduciary of any employee benefit
plan or trust or prevent or be construed to create any obligation on the part of any director or officer of dMY or any trustee or fiduciary of any employee benefit plan or trust from taking any action in his or her capacity as such director,
officer, trustee or fiduciary, provided that nothing contained in this Section 4.9 shall obviate any of such dMY Holder’s obligations under Article 1 of this Agreement. 

  
 12 

 Section 4.10 Counterparts. This Agreement may be executed in two or more
counterparts (any of which may be delivered by electronic transmission), each of which shall constitute an original, and all of which taken together shall constitute one and the same instrument. 

Section 4.11 Entire Agreement. This Agreement and the agreements referenced herein constitute the entire agreement and
understanding of the parties hereto in respect of the subject matter hereof and supersede all prior understandings, agreements or representations by or among the parties hereto to the extent they relate in any way to the subject matter hereof. 

[Signature Page Follows] 

  
 13 

 IN WITNESS WHEREOF, the dMY Holders, dMY, and the Company have each caused this Sponsor
Support Agreement to be duly executed as of the date first written above. 
  

			
	SPONSOR:
	
	DMY SPONSOR III, LLC
		
	By:	 	  

		 	Name: Harry L. You
		 	Title: Manager
	
	INSIDERS:
		
	By:	 	  

		 	Name: Harry L. You
		
	By:	 	  

		 	Name: Niccolo de Masi
		
	By:	 	  

		 	Name: Darla Anderson
		
	By:	 	  

		 	Name: Francesca Luthi
		
	By:	 	  

		 	Name: Charles Wert

  

			
	DMY:
	DMY TECHNOLOGY GROUP, INC. III
		
	By:	 	  

		 	Name: Niccolo de Masi
		 	Title: Chief Executive Officer

  

			
	COMPANY:
	
	IonQ, Inc.
		
	By:	 	  

		 	Name: Peter Chapman
		 	Title: Chief Executive Officer

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