[DEALER]

February [  ], 2024

To: Parsons Corporation

100 W. Walnut Street

Corporate Treasury

Pasadena, CA 91124

Re: [Base][Additional] Call Option Transaction

The purpose of this letter agreement (this “Confirmation”) is to confirm the terms and conditions of the call option transaction entered into between [DEALER] (“Dealer”) [, represented by [AGENT] (“Agent”),] and Parsons Corporation (“Counterparty”) as of the Trade Date specified below (the “Transaction”). This letter agreement constitutes a “Confirmation” as referred to in the ISDA Master Agreement specified below. Each party further agrees that this Confirmation together with the Agreement (as defined below) evidence a complete binding agreement between Counterparty and Dealer as to the subject matter and terms of the Transaction to which this Confirmation relates, and shall supersede all prior or contemporaneous written or oral communications with respect thereto.

The definitions and provisions contained in the 2002 ISDA Equity Derivatives Definitions (the “Equity Definitions”), as published by the International Swaps and Derivatives Association, Inc. (“ISDA”) are incorporated into this Confirmation. In the event of any inconsistency between the Equity Definitions and this Confirmation, this Confirmation shall govern. Certain defined terms used herein are based on terms that are defined in the Offering Memorandum dated February [  ], 2024 (the “Offering Memorandum”) relating to the [  ]% Convertible Senior Notes due 2029 (as originally issued by Counterparty, the “Convertible Notes” and each USD 1,000 principal amount of Convertible Notes, a “Convertible Note”) issued by Counterparty in an aggregate initial principal amount of USD [700,000,000] (as increased by [up to] an aggregate principal amount of USD [100,000,000] [if and to the extent that][pursuant to the exercise by] the Initial Purchasers (as defined herein) [exercise][of] their option to purchase additional Convertible Notes pursuant to the Purchase Agreement (as defined herein)) pursuant to an Indenture [to be] dated February [  ], 2024 between Counterparty and U.S. Bank Trust Company, National Association, as trustee (the “Indenture”). In the event of any inconsistency between the terms defined in the Offering Memorandum, the Indenture and this Confirmation, this Confirmation shall govern. The parties acknowledge that this Confirmation is entered into on the date hereof with the understanding that (i) definitions set forth in the Indenture which are also defined herein by reference to the Indenture and (ii) sections of the Indenture that are referred to herein will conform to the descriptions thereof in the Offering Memorandum. If any such definitions in the Indenture or any such sections of the Indenture differ from the descriptions thereof in the Offering Memorandum, the descriptions thereof in the Offering Memorandum will govern for purposes of this Confirmation. The parties further acknowledge that the Indenture section numbers used herein are based on the [draft of the Indenture last reviewed by Dealer as of the date of this Confirmation, and if any such section numbers are changed in the Indenture as executed, the parties will amend this Confirmation in good faith to preserve the intent of the parties][Indenture as executed]. Subject to the foregoing, references to the Indenture herein are references to the Indenture as in effect on the date of its execution, and if the Indenture is amended or supplemented following such date (other than any amendment or supplement (x) pursuant to Section 10.01(i) of the Indenture that, as determined by the Calculation Agent, conforms the Indenture to the description of Convertible Notes in the Offering Memorandum or (y) pursuant to Section 14.07(a) of the Indenture, subject, in the case of this clause (y), to the second paragraph under “Method of Adjustment” in Section ‎3), any such amendment or supplement will be disregarded for purposes of this Confirmation unless the parties agree otherwise in writing.

Each party is hereby advised, and each such party acknowledges, that the other party has engaged in, or refrained from engaging in, substantial financial transactions and has taken other material actions in reliance upon the parties’ entry into the Transaction to which this Confirmation relates on the terms and conditions set forth below.

General Terms.

Trade Date: February [  ], 2024

Effective Date: The closing date of the [initial] issuance of the Convertible Notes [issued pursuant to the option to purchase additional Convertible Notes exercised on the date hereof].

Option Style: “Modified American”, as described under “Procedures for Exercise” below.

Option Type: Call

Buyer: Counterparty

Seller: Dealer

Shares: The common stock of Counterparty, par value USD 1.00 per share (Exchange symbol “PSN”).

Number of Options: [  ]. For the avoidance of doubt, the Number of Options shall be reduced by any Options exercised by Counterparty. In no event will the Number of Options be less than zero.

Applicable Percentage: [  ]%

Option Entitlement: A number equal to the product of the Applicable Percentage and [  ].

Strike Price: USD [  ]

Cap Price: USD [  ]

Premium: USD [  ]

Premium Payment Date: The Effective Date

Exchange: New York Stock Exchange

Related Exchange(s): All Exchanges

Excluded Provisions: Section 14.03 and Section 14.04(h) of the Indenture.

Procedures for Exercise.

Conversion Date: With respect to any conversion of a Convertible Note, the date on which the “Holder” (as such term is defined in the Indenture) of such Convertible Note satisfies all of the requirements for conversion thereof as set forth in Section 14.02(b) of the Indenture; provided that if Counterparty has not delivered to Dealer a related Notice of Exercise, then in no event shall a Conversion Date be deemed to occur hereunder (and no Option shall be exercised or deemed to be exercised hereunder) with respect to any surrender of a Convertible Note for conversion in respect of which Counterparty has elected to designate a financial institution for exchange in lieu of conversion of such Convertible Note pursuant to Section 14.12 of the Indenture.

Early Conversion: (x) Any conversion of Convertible Notes with a Conversion Date occurring prior to the Free Convertibility Date or (y) any conversion of a Convertible Note in respect of which the “Holder” (as such term is defined in the Indenture) of such Convertible Note would be entitled to an increase in the “Conversion Rate” (as such term is defined in the Indenture) pursuant to Section 14.03 of the Indenture; provided that, in no event shall an Early Conversion be deemed to occur with respect to any surrender of a Convertible Note for conversion in respect of which Counterparty has elected to designate a financial institution for exchange in lieu of conversion of such Convertible Note pursuant to Section 14.12 of the Indenture.

Free Convertibility Date: October 1, 2028

Expiration Time: The Valuation Time

Expiration Date: March 1, 2029, subject to earlier exercise.

Multiple Exercise: Applicable, as described under “Automatic Exercise” and “Automatic Exercise of Remaining Repayment Options After Free Convertibility Date” below.

Automatic Exercise: Notwithstanding Section 3.4 of the Equity Definitions, on each Conversion Date occurring on or after the Free Convertibility Date, in respect of which a “[Notice of Conversion”] (as such term is defined in the Indenture) that is effective as to Counterparty has been delivered in accordance with the Indenture by the relevant converting “Holder” (as such term is defined in the Indenture), a number of Options equal to [(i)] the number of Convertible Notes in denominations of USD 1,000 as to which such Conversion Date has occurred [minus (ii) the number of

Options that are or are deemed to be automatically exercised on such Conversion Date under the Base Call Option Transaction Confirmation letter agreement dated February 21, 2024 between Dealer and Counterparty (the “Base Call Option Confirmation”),] shall be deemed to be automatically exercised; provided that such Options shall be exercised or deemed exercised only if Counterparty has provided a Notice of Exercise to Dealer in accordance with “Notice of Exercise” below.

Notwithstanding the foregoing, in no event shall the number of Options that are exercised or deemed exercised hereunder exceed the Number of Options.

Automatic Exercise of Remaining

Repayment Options After

Free Convertibility Date: Notwithstanding anything herein or in Section 3.4 of the Equity Definitions to the contrary, unless Counterparty notifies Dealer in writing prior to 5:00 p.m. (New York City time) on the Scheduled Valid Day immediately preceding the Expiration Date that it does not wish Automatic Exercise to occur, a number of Options equal to the lesser of (a) the Number of Options (after giving effect to the provisions opposite the caption “Automatic Exercise” above) as of 9:00 a.m. (New York City time) on the Expiration Date and (b) the Remaining Repayment Options [minus the number of “Remaining Options” (as defined in the Base Call Option Confirmation)] (such lesser number, the “Remaining Options”) will be deemed to be automatically exercised as if (i) a number of Convertible Notes (in denominations of USD 1,000 principal amount) equal to such number of Remaining Options were converted with a “Conversion Date” (as such term is defined in the Indenture) occurring on or after the Free Convertibility Date and (ii) the Settlement Method applied to such Convertible Notes; provided that no such automatic exercise pursuant to this paragraph will occur if the Relevant Price for each Valid Day during the Settlement Averaging Period is less than or equal to the Strike Price. “Remaining Repayment Options” shall mean the excess of (I) the aggregate number of Convertible Notes (in denominations of USD 1,000 principal amount) that were subject to Repayment Events (as defined below) during the term of the Transaction over (II) the aggregate number of Repayment Options (as defined below) that were terminated hereunder relating to Repayment Events during the term of the Transaction [plus the aggregate number of “Repayment Options” (as defined in the Base Call Option Confirmation) terminated under the Base Call Option Confirmation relating to “Repayment Events” (as defined therein) during the term of the “Transaction” under the Base Call Option Confirmation]. Counterparty shall notify Dealer in writing of the number of Remaining Repayment Options before 5:00 p.m. (New York City time) on the Scheduled Valid Day immediately preceding the Expiration Date.

Notice of Exercise: Notwithstanding anything to the contrary in the Equity Definitions or under “Automatic Exercise” above, but subject to “Automatic Exercise of Remaining Repayment Options After Free Convertibility Date” above, in order to exercise any Options relating to Convertible Notes with a Conversion Date occurring on or after the Free Convertibility Date, Counterparty must notify Dealer in writing (which, for the avoidance of doubt, may be by email) before 5:00 p.m. (New York City time) on the second Scheduled Valid Day immediately preceding the Expiration Date specifying the number of such Options; provided that if the Relevant Settlement Method for such Options is (x) Combination Settlement or (y) Cash Settlement, Dealer shall have received a separate notice (the “Notice of Final Settlement Method”) in respect of all such Convertible Notes before 5:00 p.m. (New York City time) on the Free Convertibility Date specifying (1) the Relevant Settlement Method for such Options, and (2) if the settlement method for the related Convertible Notes is not Settlement in Cash (as defined below), the fixed amount of cash per Convertible Note that Counterparty has elected to deliver to “Holders” (as such term is defined in the Indenture) of the related Convertible Notes (the “Specified Cash Amount”); provided that (a) Counterparty must make a single irrevocable election for all Options and (b) if Counterparty is electing Cash Settlement or Combination Settlement, such Settlement Method Election shall be effective only if Counterparty represents and warrants to Dealer in writing on the date of such Settlement Method Election that such election is being made in good faith and not as part of a plan or scheme to evade compliance with the federal securities laws.

Without limiting the generality of the foregoing, Counterparty acknowledges its responsibilities under applicable securities laws, and in particular Section 9 and Section 10(b) of the Exchange Act (as defined below) and the rules and regulations thereunder, in respect of any election of a settlement method with respect to the Convertible Notes and the Relevant Settlement Method.

Valuation Time: At the close of trading of the regular trading session on the Exchange; provided that if the principal trading session is extended, the Calculation Agent shall determine the Valuation Time in its commercially reasonable discretion.

Market Disruption Event: Section 6.3(a) of the Equity Definitions is hereby replaced in its entirety by the following:

“‘Market Disruption Event’ means, with respect to any date (i) the failure by the primary U.S. national or regional securities exchange or market on which the Shares are listed or admitted for trading to open for trading during its regular trading session; or (ii) the occurrence or existence prior to 1:00 p.m., New York City time, on any Scheduled Valid Day for the Shares for more than one half-hour period in the aggregate during regular trading hours of any

suspension or limitation imposed on trading (by reason of movements in price exceeding limits permitted by the relevant stock exchange or otherwise) in the Shares or in any options contracts or futures contracts relating to the Shares.”

Settlement Terms.

Settlement Method: For any Option, Net Share Settlement; provided that if the Relevant Settlement Method set forth below for such Option is not Net Share Settlement, then the Settlement Method for such Option shall be such Relevant Settlement Method, but only if Counterparty shall have delivered to Dealer a valid Notice of Final Settlement Method as set forth above for such Option.

Relevant Settlement Method: In respect of any Option:

(i) if Counterparty has elected, or is deemed to have elected, to settle its conversion obligations in respect of the related Convertible Note in a combination of cash and Shares pursuant to Section 14.02(a) of the Indenture with a Specified Cash Amount equal to USD 1,000, then the Relevant Settlement Method for such Option shall be Net Share Settlement;

(ii) if Counterparty has elected to settle its conversion obligations in respect of the related Convertible Note in a combination of cash and Shares pursuant to Section 14.02(a) of the Indenture with a Specified Cash Amount greater than USD 1,000, then the Relevant Settlement Method for such Option shall be Combination Settlement; and

(iii) if Counterparty has elected to settle its conversion obligations in respect of the related Convertible Note entirely in cash pursuant to Section 14.02(a) of the Indenture (such settlement method, “Settlement in Cash”), then the Relevant Settlement Method for such Option shall be Cash Settlement.

Net Share Settlement: If Net Share Settlement is applicable to any Option exercised or deemed exercised hereunder, Dealer will deliver to Counterparty, on the relevant Settlement Date for each such Option, a number of Shares (the “Net Share Settlement Amount”) equal to the sum, for each Valid Day during the Settlement Averaging Period for each such Option, of (i) (a) the Daily Option Value for such Valid Day, divided by (b) the Relevant Price on such Valid Day, divided by (ii) the number of Valid Days in the Settlement Averaging Period; provided that in no event shall the Net Share Settlement Amount for any Option exceed a number of Shares equal to the Applicable Limit for such Option divided by the Applicable Limit Price on the Settlement Date for such Option.

Dealer will pay cash in lieu of delivering any fractional Shares to be delivered with respect to any Net Share Settlement Amount valued at the Relevant Price for the last Valid Day of the Settlement Averaging Period.

Combination Settlement: If Combination Settlement is applicable to any Option exercised or deemed exercised hereunder, Dealer will pay or deliver, as the case may be, to Counterparty, on the relevant Settlement Date for each such Option:

(i) cash (the “Combination Settlement Cash Amount”) equal to the sum, for each Valid Day during the Settlement Averaging Period for such Option, of (A) an amount (the “Daily Combination Settlement Cash Amount”) equal to the lesser of (1) the product of (x) the Applicable Percentage and (y) the Specified Cash Amount minus USD 1,000 and (2) the Daily Option Value, divided by (B) the number of Valid Days in the Settlement Averaging Period; provided that if the calculation in clause (A) above results in zero or a negative number for any Valid Day, the Daily Combination Settlement Cash Amount for such Valid Day shall be deemed to be zero; and

(ii) Shares (the “Combination Settlement Share Amount”) equal to the sum, for each Valid Day during the Settlement Averaging Period for such Option, of a number of Shares for such Valid Day (the “Daily Combination Settlement Share Amount”) equal to (A) (1) the Daily Option Value on such Valid Day minus the Daily Combination Settlement Cash Amount for such Valid Day, divided by (2) the Relevant Price on such Valid Day, divided by (B) the number of Valid Days in the Settlement Averaging Period; provided that if the calculation in sub-clause (A)(1) above results in zero or a negative number for any Valid Day, the Daily Combination Settlement Share Amount for such Valid Day shall be deemed to be zero;

provided that in no event shall the sum of (x) the Combination Settlement Cash Amount for any Option, (y) the Combination Settlement Share Amount (not including any such amount representing a fractional share) for such Option multiplied by the Applicable Limit Price on the Settlement Date for such Option and (z) the cash to be paid by Dealer in lieu of a fractional share, exceed the Applicable Limit for such Option.

Dealer will pay cash in lieu of delivering any fractional Shares to be delivered with respect to any Combination Settlement Share Amount valued at the Relevant Price for the last Valid Day of the Settlement Averaging Period.

Cash Settlement: If Cash Settlement is applicable to any Option exercised or deemed exercised hereunder, in lieu of Section 8.1 of the

Equity Definitions, Dealer will pay to Counterparty, on the relevant Settlement Date for each such Option, an amount of cash (the “Cash Settlement Amount”) equal to the sum, for each Valid Day during the Settlement Averaging Period for such Option, of (i) the Daily Option Value for such Valid Day, divided by (ii) the number of Valid Days in the Settlement Averaging Period; provided that in no event shall the Cash Settlement Amount for any Option exceed the Applicable Limit for such Option.

Daily Option Value: For any Valid Day, an amount equal to (i) the Option Entitlement on such Valid Day, multiplied by (ii) (A) the lesser of the Relevant Price on such Valid Day and the Cap Price, less (B) the Strike Price on such Valid Day; provided that if the calculation contained in clause (ii) above results in a negative number, the Daily Option Value for such Valid Day shall be deemed to be zero. In no event will the Daily Option Value be less than zero.

Applicable Limit: For any Option, an amount of cash equal to the Applicable Percentage multiplied by the excess of (i) the aggregate of (A) the amount of cash paid to the “Holder” (as such term is defined in the Indenture) of the related Convertible Note upon conversion of such Convertible Note and (B) the number of Shares, if any, delivered to the “Holder” (as such term is defined in the Indenture) of the related Convertible Note upon conversion of such Convertible Note multiplied by the Applicable Limit Price on the Settlement Date for such Option, over (ii) USD 1,000.

Applicable Limit Price: On any day, the opening price as displayed under the heading “Op” on Bloomberg page PSN<equity> (or any successor thereto).

Valid Day: Any day on which (i) trading in the Shares generally occurs on the Exchange or, if the Shares are not then listed on the Exchange, on the principal other U.S. national or regional securities exchange on which the Shares are then listed or, if the Shares are not then listed on a U.S. national or regional securities exchange, on the principal other market on which the Shares are then listed or admitted for trading; and (ii) there is no Market Disruption Event. If the Shares are not so listed or admitted for trading, then “Valid Day” means a Business Day.

Scheduled Valid Day: Any day that is scheduled to be a Valid Day on the principal U.S. national or regional securities exchange or market on which the Shares are then listed or admitted for trading. If the Shares are not so listed or traded, then “Scheduled Valid Day” means a Business Day.

Business Day: Any day other than a Saturday, a Sunday or any day on which the Federal Reserve Bank of New York is authorized or required by law or executive order to close or be closed.

Relevant Price: On any Valid Day, the per Share volume-weighted average price as displayed under the heading “Bloomberg VWAP”

on Bloomberg page “PSN <equity> AQR” (or its equivalent successor if such page is not available) in respect of the period from the scheduled open of trading until the scheduled close of trading of the primary trading session on such Valid Day (or if such volume-weighted average price is unavailable at such time, the market value of one Share on such Valid Day, as determined by the Calculation Agent in a commercially reasonable manner using, if practicable, a volume-weighted average method). The Relevant Price will be determined without regard to after-hours trading or any other trading outside of the regular trading session trading hours.

Settlement Averaging Period: For any Option and regardless of the Settlement Method applicable to such Option, the 50 consecutive Valid Days commencing on, and including, the 51st Scheduled Valid Day immediately prior to the Expiration Date.

Settlement Date: For any Option, the second Business Day immediately following the final Valid Day of the Settlement Averaging Period for such Option.

Settlement Currency: USD

Other Applicable Provisions: The provisions of Sections 9.1(c), 9.8, 9.9 and 9.11 of the Equity Definitions will be applicable, except that all references in such provisions to “Physically-settled” shall be read as references to “Share Settled”. “Share Settled” in relation to any Option means that Net Share Settlement or Combination Settlement is applicable to that Option.

Representation and Agreement: Notwithstanding anything to the contrary in the Equity Definitions (including, but not limited to, Section 9.11 thereof), the parties acknowledge that (i) any Shares delivered to Counterparty shall be, upon delivery, subject to restrictions and limitations arising from Counterparty’s status as issuer of the Shares under applicable securities laws, (ii) Dealer may deliver any Shares required to be delivered hereunder in certificated form in lieu of delivery through the Clearance System and (iii) any Shares delivered to Counterparty may be “restricted securities” (as defined in Rule 144 under the Securities Act of 1933, as amended (the “Securities Act”)).

Adjustments applicable to the Transaction:

Potential Adjustment Events: Notwithstanding Section 11.2(e) of the Equity Definitions, a “Potential Adjustment Event” means an occurrence of any event or condition, as set forth in any Dilution Adjustment Provision, that would result in an adjustment under the Indenture to the [“Conversion Rate” or the composition of a “unit of Reference Property” or to any “Last Reported Sale Price,” “Daily Measurement Value,” “Daily Conversion Value,” “Daily Settlement Amount” or “Daily VWAP”] (each such term as defined in the

Indenture). For the avoidance of doubt, Dealer shall not have any delivery or payment obligation hereunder, and except as set forth in Section 9(x), no adjustment shall be made to the terms of the Transaction, on account of (x) any distribution of cash, property or securities by Counterparty to “Holders” (as such term is defined in the Indenture) (upon conversion or otherwise) or (y) any other transaction in which “Holders” (as such term is defined in the Indenture) are entitled to participate, in each case, in lieu of an adjustment under the Indenture of the type referred to in the immediately preceding sentence (including, without limitation, pursuant to the fourth sentence of the first paragraph of Section 14.04(c) of the Indenture or the fourth sentence of Section 14.04(d) of the Indenture).

Method of Adjustment: Calculation Agent Adjustment, which means that, notwithstanding Section 11.2(c) of the Equity Definitions, upon any Potential Adjustment Event, the Calculation Agent shall make an adjustment to any one or more of the Strike Price, Number of Options, Option Entitlement and any other variable relevant to the exercise, settlement or payment for the Transaction that corresponds to the adjustments to the Convertible Notes under the Indenture; provided that the parties agree that (x) open market Share repurchases at prevailing market prices and (y) Share repurchases through a dealer pursuant to accelerated share repurchases, forward contracts or similar transactions that are entered into at prevailing market prices and in accordance with customary market terms for transactions of such type to repurchase the Shares shall not be considered Potential Adjustment Events, in each case, to the extent that, after giving effect to such transactions, the aggregate number of Shares repurchased during the term of the Transaction pursuant to all transactions described in this proviso would not reduce the number of Shares outstanding to be less than [ ] Shares, as determined by the Calculation Agent and as adjusted by the Calculation Agent to account for any subdivision or combination with respect to the Shares.

Notwithstanding the foregoing and “Consequences of Merger Events / Tender Offers” below:

(i) if the Calculation Agent in good faith disagrees with any adjustment to the Convertible Notes that involves an exercise of discretion by Counterparty or its board of directors (including, without limitation, pursuant to Section 14.05 of the Indenture, Section 14.07(a) of the Indenture or any supplemental indenture entered into thereunder or in connection with any proportional adjustment or the determination of the fair value of any securities, property, rights or other assets), then in each such case, the Calculation Agent will, in good faith and in a commercially reasonable manner and, if applicable, consistent with the

methodology set forth in the Indenture, determine the adjustment to be made to any one or more of the Strike Price, Number of Options, Option Entitlement and any other variable relevant to the exercise, settlement or payment for the Transaction in a commercially reasonable manner;

(ii) in connection with any Potential Adjustment Event as a result of an event or condition set forth in Section 14.04(b) of the Indenture or Section 14.04(c) of the Indenture where, in either case, the period for determining “Y” (as such term is used in Section 14.04(b) of the Indenture) or “SP0” (as such term is used in Section 14.04(c) of the Indenture), as the case may be, begins before Counterparty has publicly announced the event or condition giving rise to such Potential Adjustment Event, then the Calculation Agent shall, in good faith and in a commercially reasonable manner, have the right to adjust any variable relevant to the exercise, settlement or payment for the Transaction as appropriate to reflect the costs (including, but not limited to, hedging mismatches and market losses) and expenses incurred by Dealer in connection with its hedging activities, with such adjustments made assuming that Dealer maintains commercially reasonable hedge positions, as a result of such event or condition not having been publicly announced prior to the beginning of such period; and

(iii) if any Potential Adjustment Event is declared and (a) the event or condition giving rise to such Potential Adjustment Event is subsequently amended, modified, cancelled or abandoned, (b) the “Conversion Rate” (as such term is defined in the Indenture) is otherwise not adjusted at the time or in the manner contemplated by the relevant Dilution Adjustment Provision based on such declaration or (c) the “Conversion Rate” (as such term is defined in the Indenture) is adjusted as a result of such Potential Adjustment Event and subsequently re-adjusted (each of clauses (a), (b) and (c), a “Potential Adjustment Event Change”) then, in each case, the Calculation Agent shall, in good faith and in a commercially reasonable manner, have the right to adjust any variable relevant to the exercise, settlement or payment for the Transaction as appropriate to reflect the costs (including, but not limited to, hedging mismatches and market losses) and expenses incurred by Dealer in connection with its hedging activities, with such adjustments made assuming that Dealer maintains commercially

reasonable hedge positions, as a result of such Potential Adjustment Event Change.

Dilution Adjustment Provisions: Sections 14.04(a), (b), (c), (d) and (e) and Section 14.05 of the Indenture.

Extraordinary Events applicable to the Transaction:

Merger Events: Applicable; provided that notwithstanding Section 12.1(b) of the Equity Definitions, a “Merger Event” means the occurrence of any event or condition set forth in the definition of “Share Exchange Event” in Section 14.07(a) of the Indenture.

Tender Offers: Applicable; provided that notwithstanding Section 12.1(d) of the Equity Definitions, a “[Tender Offer]” means the occurrence of any event or condition set forth in Section 14.04(e) of the Indenture.

Consequences of Merger Events/

Tender Offers: Notwithstanding Section 12.2 and Section 12.3 of the Equity Definitions, upon the occurrence of a Merger Event or a Tender Offer, the Calculation Agent shall make a corresponding adjustment in respect of any adjustment under the Indenture to any one or more of the nature of the Shares (in the case of a Merger Event), Strike Price, Number of Options, Option Entitlement and any other variable relevant to the exercise, settlement or payment for the Transaction, subject to the second paragraph under “Method of Adjustment”; provided, however, that such adjustment shall be made without regard to any adjustment to the “Conversion Rate” (as such term is defined in the Indenture) pursuant to any Excluded Provision; provided further that if, with respect to a Merger Event or a Tender Offer, (i) the consideration for the Shares includes (or, at the option of a holder of Shares, may include) shares of an entity or person that is not a corporation or is not organized under the laws of the United States, any State thereof or the District of Columbia or (ii) the Counterparty to the Transaction following such Merger Event or Tender Offer will not be a corporation organized under the laws of the United States, any State thereof or the District of Columbia, then, in either case, Cancellation and Payment (Calculation Agent Determination) may apply at Dealer’s reasonable election; provided further that, for the avoidance of doubt, adjustments shall be made pursuant to the provisions set forth above regardless of whether any Merger Event or Tender Offer gives rise to an Early Conversion.

Consequences of Announcement Events: Modified Calculation Agent Adjustment as set forth in Section 12.3(d) of the Equity Definitions; provided that, in respect of an Announcement Event, (w) references to “Tender Offer” shall be replaced by references to “Announcement Event” and references to “Tender Offer Date” shall be replaced by references to “date of such Announcement Event”, (x) the phrase “exercise,

settlement, payment or any other terms of the Transaction (including, without limitation, the spread)” shall be replaced with the phrase “Cap Price (provided that in no event shall the Cap Price be less than the Strike Price)”, (y) the phrases “whether within a commercially reasonable (as determined by the Calculation Agent) period of time prior to or after the Announcement Event,” shall be inserted prior to the word “which” in the seventh line, and (z) for the avoidance of doubt, the Calculation Agent shall, in good faith and in a commercially reasonable manner, determine whether the relevant Announcement Event has had a material economic effect on the Transaction (and, if so, shall adjust the Cap Price accordingly) on one or more occasions on or after the date of the Announcement Event up to, and including, the Expiration Date, any Early Termination Date and/or any other date of cancellation, it being understood that (i) any adjustment in respect of an Announcement Event shall take into account any earlier adjustment relating to the same Announcement Event and (ii) such adjustment shall be made without duplication of any other adjustment hereunder. An Announcement Event shall be an “Extraordinary Event” for purposes of the Equity Definitions, to which Article 12 of the Equity Definitions is applicable.

Announcement Event: (i) The public announcement by Issuer, any affiliate of Issuer, any agent of Issuer or any Valid Third Party Entity (any such person or entity, a “Relevant Party”) of (x) any transaction or event that, if completed, would constitute a Merger Event or Tender Offer, (y) any potential acquisition or disposition by Issuer and/or its subsidiaries where the aggregate consideration exceeds 35% of the market capitalization of Issuer as of the date of such announcement (an “Acquisition Transaction”) or (z) the intention to enter into a Merger Event or Tender Offer or an Acquisition Transaction, (ii) the public announcement by Issuer of an intention to solicit or enter into, or to explore strategic alternatives or other similar undertaking that may include, a Merger Event or Tender Offer or an Acquisition Transaction or (iii) any subsequent public announcement by a Relevant Party (in the case of a transaction or intention pursuant to clause (i)) or Issuer (in the case of a transaction or intention pursuant to clause (ii)) of a change to a transaction or intention that is the subject of an announcement of the type described in clause (i) or (ii) of this sentence (including, without limitation, a new announcement, whether or not by the same party, relating to such a transaction or intention or the announcement of a withdrawal from, or the abandonment or discontinuation of, such a transaction or intention), as determined by the Calculation Agent. For the avoidance of doubt, the occurrence of an Announcement Event with respect to any transaction or intention shall not preclude the occurrence of a later Announcement Event with respect to such transaction or intention. For purposes of this definition of “Announcement Event,” (A) “Merger Event” shall mean

such term as defined under Section 12.1(b) of the Equity Definitions (but, for the avoidance of doubt, the remainder of the definition of “Merger Event” in Section 12.1(b) of the Equity Definitions following the definition of “Reverse Merger” therein shall be disregarded) and (B) “Tender Offer” shall mean such term as defined under Section 12.1(d) of the Equity Definitions; provided that (1) Section 12.1(d) of the Equity Definitions is hereby amended by (x) replacing “10%” with “20%” in the third line thereof and (y) replacing the words “voting shares of the Issuer” in the fourth line thereof with the word “Shares” and (2) Section 12.1(e) of the Equity Definitions is hereby amended by replacing the words “voting shares” in the first line thereof with the word “Shares”.

Valid Third Party Entity: In respect of any transaction or event, any third party (or affiliate or agent thereof) that has a bona fide intent to enter into or consummate such transaction or event (it being understood and agreed that in determining, in a commercially reasonable manner, whether such third party has such a bona fide intent, the Calculation Agent shall take into consideration whether the relevant announcement by such party has had a material economic effect on the Shares and/or Options on the Shares).

Nationalization, Insolvency or Delisting: Cancellation and Payment (Calculation Agent Determination); provided that, in addition to the provisions of Section 12.6(a)(iii) of the Equity Definitions, it will also constitute a Delisting if the Exchange is located in the United States and the Shares are not immediately re-listed, re-traded or re-quoted on any of the New York Stock Exchange, The Nasdaq Global Select Market or The Nasdaq Global Market (or their respective successors); if the Shares are immediately re-listed, re-traded or re-quoted on any of the New York Stock Exchange, The Nasdaq Global Select Market or The Nasdaq Global Market (or their respective successors), such exchange or quotation system shall thereafter be deemed to be the Exchange.

Additional Disruption Events:

Change in Law: Applicable; provided that Section 12.9(a)(ii) of the Equity Definitions is hereby amended by (i) replacing the phrase “the interpretation” in the third line thereof with the phrase “, or public announcement of, the formal or informal interpretation”, (ii) replacing the word “Shares” where it appears in clause (X) thereof with the words “Hedge Position” and (iii) replacing the parenthetical beginning after the word “regulation” in the second line thereof with the words “(including, for the avoidance of doubt and without limitation, (x) any tax law or (y) adoption, effectiveness or promulgation of new regulations authorized or mandated by existing statute)”.

Failure to Deliver: Applicable

Hedging Disruption: Applicable; provided that:

(i) Section 12.9(a)(v) of the Equity Definitions is hereby amended by inserting the following two phrases at the end of such Section:

“, provided that any such inability that occurs solely due to the deterioration of the creditworthiness of the Hedging Party shall not be deemed a Hedging Disruption. For the avoidance of doubt, the term “equity price risk” shall be deemed to include, but shall not be limited to, stock price and volatility risk. And, for the further avoidance of doubt, any such transactions or assets referred to in phrases (A) or (B) above must be available on commercially reasonable pricing terms.”; and

(ii) Section 12.9(b)(iii) of the Equity Definitions is hereby amended by inserting in the third line thereof, after the words “to terminate the Transaction”, the words “or a portion of the Transaction affected by such Hedging Disruption”.

Increased Cost of Hedging: Not Applicable

Hedging Party: For all applicable Additional Disruption Events, Dealer.

Determining Party: For all applicable Extraordinary Events, Dealer. All calculations and determinations by the Determining Party shall be made in good faith and in a commercially reasonable manner. The Determining Party will promptly (but in any event within five (5) Exchange Business Days), upon written notice from Counterparty, provide a statement displaying in reasonable detail the basis for such determination or calculation, as the case may be (including any quotations, market data or information from internal or external sources used in making such determination or calculation, it being understood that the Determining Party shall not be required to disclose any confidential information or proprietary models used by it in connection with such determination or calculation, as the case may be).

Non-Reliance: Applicable

Agreements and Acknowledgments

Regarding Hedging Activities: Applicable

Additional Acknowledgments: Applicable

Hedging Adjustment: For the avoidance of doubt, whenever Hedging Party, Determining Party or the Calculation Agent makes an adjustment, calculation or determination permitted or required to be made pursuant to the terms of this Confirmation or the Equity Definitions to take into account the effect of any event (other than an adjustment, calculation or determination made by reference to the Indenture), the Calculation Agent, Determining Party or Hedging Party, as the case may be, shall make such adjustment, calculation or determination in a commercially

reasonable manner and by reference to the effect of such event on Dealer assuming that Dealer maintains a commercially reasonable hedge position.

To be provided by Counterparty.

Account for delivery of Shares to Counterparty:

To be provided by Counterparty.

[Bank:] [  ]

[SWIFT:] [  ]

[Bank Routing:] [  ]

[Acct Name:] [  ]

[Acct No.:] [  ]

Account for delivery of Shares from Dealer:

[  ]

To: Parsons Corporation

14291 Park Meadow Drive, Suite 100

Chantilly, Virginia 20151

Attn: Michael R. Kolloway, Chief Legal Officer and Secretary

Telephone: +1-703-988-8500 and +1-872-202-2576

Email: Mike.Kolloway@parsons.com

With a copy to:

Paul Walker-Lanz, Vice President, Treasurer

Telephone: +1-626-314-0219

Email: paul.walker@parsons.com

[  ]

Attention: [  ]

Telephone: [  ]

Email: [  ]

[With a copy to:

[  ]

Attention: [  ]

Telephone: [  ]

Email: [  ]]

Each of the representations and warranties of Counterparty set forth in Section 1 of the Purchase Agreement (the “Purchase Agreement”) dated as of February [  ], 2024, between Counterparty and BofA Securities, Inc., Goldman Sachs & Co. LLC and J.P. Morgan Securities LLC, as representatives of the Initial Purchasers party thereto (the “Initial Purchasers”), are true and correct and are hereby deemed to be repeated to Dealer

as if set forth herein. Counterparty hereby further represents and warrants to Dealer on the date hereof and on and as of the Premium Payment Date that:

(A) With respect to any Transfer Options, Counterparty shall not be released from its notice and indemnification obligations pursuant to Section 9(b) or any obligations under Section 9(n) or 9(s) of this Confirmation;

(B) Any Transfer Options shall only be transferred or assigned to a third party that is a United States person (as defined in the Internal Revenue Code of 1986, as amended (the “Code”));

(C) Such transfer or assignment shall be effected on terms, including any reasonable undertakings by such third party (including, but not limited to, an undertaking with respect to compliance with applicable securities laws in a manner that, in the reasonable judgment of Dealer, will not expose Dealer to material risks under applicable securities laws) and execution of any documentation and delivery of legal opinions with respect to securities laws and other matters by such third party and Counterparty, as are requested and reasonably satisfactory to Dealer;

(D) Dealer will not, as a result of such transfer and assignment, be required to pay the transferee on any payment date an amount under Section 2(d)(i)(4) of the Agreement greater than an amount that Dealer would have been required to pay to Counterparty in the absence of such transfer and assignment;

(E) Dealer will not, as a result of such transfer or assignment, receive from the transferee or assignee on any payment date (after accounting for amounts paid by the transferee or assignee under Section 2(d)(i)(4) of the Agreement as well as any withholding or deduction of Tax from the payment) an amount less than it would have been entitled to receive from Counterparty in the absence of such transfer or assignment;

(F) An Event of Default, Potential Event of Default or Termination Event will not occur as a result of such transfer and assignment;

(G) Without limiting the generality of clause (B), the transferee or assignee shall make such Payee Tax Representations and provide such tax documentation as may be reasonably requested by Dealer to permit Dealer to determine that results described in clauses (D) and (E) will not occur upon or after such transfer and assignment; and

(H) Counterparty shall be responsible for all reasonable costs and expenses, including reasonable counsel fees, incurred by Dealer in connection with such transfer or assignment.

(A) Counterparty shall, within five Scheduled Trading Days of the Conversion Date for such Early Conversion, provide written notice (an “Early Conversion Notice”) to Dealer specifying the number of Convertible Notes surrendered for conversion on such Conversion Date (such Convertible Notes, the “Affected Convertible Notes”), and the giving of such Early Conversion Notice shall constitute an Additional Termination Event as provided in this clause ‎(i);

(B) upon receipt of any such Early Conversion Notice, Dealer shall designate an Exchange Business Day as an Early Termination Date (which Exchange Business Day shall be on or as promptly as reasonably practicable after the related settlement date for such Affected Convertible Notes) with respect to the portion of the Transaction corresponding to a number of Options (the “Affected Number of Options”) equal to the lesser of (x) the number of Affected Convertible Notes [minus the “Affected Number of Options” (as defined in the Base Call Option Confirmation), if any, that relate to such Affected Convertible Notes] and (y) the Number of Options as of the Conversion Date for such Early Conversion;

(C) any payment hereunder with respect to such termination shall be calculated pursuant to Section 6 of the Agreement as if (x) an Early Termination Date had been designated in respect of a Transaction having terms identical to the Transaction and a Number of Options equal to the Affected Number of Options, (y) Counterparty were the sole Affected Party with respect to such Additional Termination Event and (z) the terminated portion of the Transaction were the sole Affected Transaction; provided that the amount payable with respect to such termination shall not be greater than (1) the Applicable Percentage, multiplied by (2) the Affected Number of Options, multiplied by (3) (x) the sum of (i) the amount of cash paid to the “Holder” (as such term is defined in the Indenture) of an Affected Convertible Note upon conversion of such Affected Convertible Note and (ii) the number of Shares delivered (if any) to the “Holder” (as such term is defined in the Indenture) of an Affected Convertible Note upon conversion of such Affected Convertible Note, multiplied by the Applicable Limit Price on the settlement date for the conversion of such Affected Convertible Note (the “Conversion Settlement Date”), minus (y) the Synthetic Instrument Adjusted Issue Price determined by the Calculation Agent by reference to the Conversion Settlement Date. “Synthetic Instrument Adjusted Issue Price” shall mean the amount determined by the Calculation Agent by reference to the table set forth below (the “Synthetic Instrument AIP Table”). If the relevant Conversion Settlement Date is not listed in the Synthetic Instrument AIP Table, the amount in the preceding sentence shall be determined by the Calculation Agent by reference to the Synthetic Instrument AIP Table, using a linear interpolation between the lower and higher Synthetic Instrument Adjusted Issue Prices for the Conversion Settlement Dates immediately preceding and immediately following the relevant Conversion Settlement Date.

(D) for the avoidance of doubt, in determining the amount payable in respect of such Affected Transaction pursuant to Section 6 of the Agreement, the Calculation Agent shall assume that (x) the relevant Early Conversion and any conversions, adjustments, agreements, payments, deliveries or acquisitions by or on behalf of Counterparty leading thereto had not occurred, (y) no adjustments to the “Conversion Rate” (as such term is defined in the Indenture) have occurred pursuant to any Excluded Provision and (z) the corresponding Convertible Notes remain outstanding as if the circumstances related to such Early Conversion had not occurred; and

(E) the Transaction shall remain in full force and effect, except that, as of the Conversion Date for such Early Conversion, the Number of Options shall be reduced by the Affected Number of Options.

Share Termination Alternative: If applicable, Dealer shall deliver to Counterparty the Share Termination Delivery Property on, or within a commercially reasonable period of time after, the date when the relevant Payment Obligation would otherwise be due pursuant to Section 12.7 or 12.9 of the Equity Definitions or Section 6(d)(ii) and 6(e) of the Agreement, as applicable, in satisfaction of such Payment Obligation in the manner reasonably requested by Counterparty free of payment.

Share Termination Delivery Property: A number of Share Termination Delivery Units, as calculated by the Calculation Agent, equal to the Payment Obligation divided by the Share Termination Unit Price. The Calculation Agent shall adjust the Share Termination Delivery Property by replacing any fractional portion of a security therein with an amount of cash equal to the value of such fractional security based on the values used to calculate the Share Termination Unit Price.

Share Termination Unit Price: The value to Dealer of property contained in one Share Termination Delivery Unit, as determined by the Calculation Agent in its discretion by commercially reasonable means and notified by the Calculation Agent to Dealer at the time of notification of the Payment Obligation. For the avoidance of doubt, the parties agree that in determining the Share Termination Delivery Unit Price the Calculation Agent may consider the purchase price paid in connection with the purchase of Share Termination Delivery Property.

Share Termination Delivery Unit: One Share or, if the Shares have changed into cash or any other property or the right to receive cash or any other property as the result of a Nationalization, Insolvency or Merger Event (any such cash or other property, the “Exchange Property”), a unit consisting of the type and amount of such Exchange Property received by a holder of one Share (without consideration of any requirement to pay cash or other consideration in lieu of fractional amounts of any securities) in such Nationalization, Insolvency or Merger Event, as determined by the Calculation Agent.

Failure to Deliver: Applicable

Other Applicable Provisions: If Share Termination Alternative is applicable, the provisions of Sections 9.8, 9.9 and 9.11 (as modified above) of the Equity Definitions and the provisions set forth opposite the caption “Representation and Agreement” in Section 2 will be applicable, except that all references in such provisions to “Physically-settled” shall be read as references to “Share Termination Settled” and all references to “Shares” shall be read as references to “Share Termination Delivery Units”. “Share Termination Settled” in relation to the Transaction means that Share Termination Alternative is applicable to the Transaction.

[Signature Pages Follow.]

Please confirm that the foregoing correctly sets forth the terms of our agreement by executing this Confirmation and returning it to [Dealer].

Very truly yours,

Accepted and confirmed
as of the Trade Date: