GSK acquisition cashes out RAPT (RAPT) CFO shares and options

Rhea-AI Filing Summary

RAPT Therapeutics’ chief financial officer, Rodney KB Young, reported the cash-out of equity awards tied to the company’s acquisition by GlaxoSmithKline. The filing shows dispositions of several employee stock options back to the issuer and the tender of 3,304 common shares.

Under a merger agreement with GlaxoSmithKline LLC and its affiliates, all RAPT common shares were acquired for $58.00 per share in cash. Stock options with exercise prices below this offer price were accelerated, then cancelled in exchange for cash equal to their in-the-money value.

Certain unvested options granted after March 1, 2025 were instead converted into cash-based awards of the GSK parent. These converted awards retain the original vesting conditions but pay out 50% at closing and 50% nine months later, with full acceleration if the holder is involuntarily terminated within that nine-month period.

Insights

Equity compensation and M&A analyst

CFO’s stock and options are cashed out or converted as part of the agreed GSK takeover, not sold on the open market.

The transactions reflect how RAPT Therapeutics handled insider equity in its merger with GlaxoSmithKline LLC. Common shares held by the CFO were tendered for $58.00 per share in cash, while in-the-money options were accelerated, cancelled, and converted into a right to receive cash equal to their intrinsic value.

Unvested options granted after March 1, 2025 became cash-based awards of the GSK parent, maintaining similar vesting terms. These converted awards pay 50% at closing and 50% nine months later, with full payout if an involuntary termination occurs in that period. Overall, this is standard merger consideration treatment rather than discretionary insider selling, so it does not materially change the investment thesis beyond the already-announced acquisition.

SEC Form 4

FORM 4

UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934
or Section 30(h) of the Investment Company Act of 1940

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X

Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

Check this box to indicate that a transaction was made pursuant to a contract, instruction or written plan for the purchase or sale of equity securities of the issuer that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.

1. Name and Address of Reporting Person^*

Young Rodney KB

(Last) (First) (Middle)

C/O RAPT THERAPEUTICS, INC.

561 ECCLES AVENUE

(Street)

SOUTH SAN FRANCISCO CA 94080

(City) (State) (Zip)

2. Issuer Name and Ticker or Trading Symbol
RAPT Therapeutics, Inc. [ RAPT ]

5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)

	Director		10% Owner
X	Officer (give title below)		Other (specify below)
	CHIEF FINANCIAL OFFICER

3. Date of Earliest Transaction (Month/Day/Year)
03/03/2026

4. If Amendment, Date of Original Filed (Month/Day/Year)

6. Individual or Joint/Group Filing (Check Applicable Line)

X	Form filed by One Reporting Person
	Form filed by More than One Reporting Person

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	3. Transaction Code (Instr. 8)		4. Securities Acquired (A) or Disposed Of (D) (Instr. 3, 4 and 5)			5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4)	6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
			Code	V	Amount	(A) or (D)	Price
Common Stock	03/03/2026		U(1)(2)		3,304(3)	D	(4)	0	D

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Transaction Date (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	4. Transaction Code (Instr. 8)		5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5)		6. Date Exercisable and Expiration Date (Month/Day/Year)		7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4)		8. Price of Derivative Security (Instr. 5)	9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)	10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
				Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares
Employee Stock Option (right to buy)(5)	$12.56	03/03/2026		D(1)(2)			17,501	(6)	(6)	Common Stock	17,501	(6)	0	D
Employee Stock Option (right to buy)(5)	$12.56	03/03/2026		D(1)(2)			7,500	(6)	(6)	Common Stock	7,500	(6)	0	D
Employee Stock Option (right to buy)(5)	$12.56	03/03/2026		D(1)(2)			8,125	(6)	(6)	Common Stock	8,125	(6)	0	D
Employee Stock Option (right to buy)(5)	$12.56	03/03/2026		D(1)(2)			8,501	(6)	(6)	Common Stock	8,501	(6)	0	D
Employee Stock Option (right to buy)(5)	$12.56	03/03/2026		D(1)(2)			11,251	(6)	(6)	Common Stock	11,251	(6)	0	D
Employee Stock Option (right to buy)(5)	$9.12	03/03/2026		D(1)(2)			80,250	(6)	(6)	Common Stock	80,250	(6)	0	D
Employee Stock Option (right to buy)	$7.43	03/03/2026		D(1)(2)			69,271	(7)(8)	(7)(8)	Common Stock	69,271	(7)(8)	49,479	D

Explanation of Responses:

1. The Issuer entered into an Agreement and Plan of Merger, dated January 19, 2026 (the "Merger Agreement") with GlaxoSmithKline LLC, a Delaware limited liability company ("Parent"), Redrose Acquisition Co., a Delaware corporation and a wholly owned subsidiary of Parent ("Purchaser") and solely for purposes of providing a guaranty pursuant to Section 8.11 of the Merger Agreement, GSK plc, a public limited company organized under the laws of England and Wales. Pursuant to the Merger Agreement, Purchaser completed a tender offer to acquire all of the issued and outstanding shares of common stock of the Issuer, for $58.00 per share (the "Offer Price"), in cash, without interest and subject to any applicable withholding of taxes. On March 3, 2026, Purchaser merged with and into the Issuer, with the Issuer surviving as an indirect wholly owned subsidiary of Parent (the effective time of such merger, the "Effective Time").

2. This Form 4 reports securities transacted pursuant to the Merger Agreement.

3. The number of shares was adjusted to reflect the 1-for-8 reverse stock split effected by the Issuer on June 16, 2025.

4. Pursuant to the terms of the Merger Agreement, at the Effective Time, each share of common stock held by the Reporting Person was tendered in exchange for the Offer Price.

5. The number of shares underlying this option and the exercise price were adjusted to reflect the 1-for-8 reverse stock split effected by the Issuer on June 16, 2025.

6. Pursuant to the terms of the Merger Agreement, each stock option Pursuant to the terms of the Merger Agreement, each stock option that was outstanding as of immediately prior to the Effective Time, whether vested or unvested, was accelerated and became fully vested and exercisable as of immediately prior to the Effective Time. At the Effective Time, each stock option that was outstanding and unexercised as of immediately before the Effective Time and which had a per share exercise price that was less than Offer Price was cancelled and converted solely into the right to receive cash in an amount equal to the product of (i) the total number of shares subject to such stock option immediately prior to the Effective Time, multiplied by (ii) the excess of (x) the Offer Price, over (y) the exercise price payable per share under such stock option.

7. Pursuant to the terms of the Merger Agreement, each stock option that is unvested as of immediately prior to the Effective Time and was granted after March 1, 2025 (a "2025 Option") was cancelled and converted into a cash-based award of Parent (a "Converted Option"), which shall entitle the holder thereof to receive an amount in cash equal to the Option Consideration (the "Converted Option Consideration").

8. Each Converted Option (and the right to receive the Converted Option Consideration) shall be subject to the same terms and conditions (including vesting, forfeiture and acceleration provisions) that were applicable to the corresponding 2025 Option immediately prior to the Effective Time; provided, that (i) the Converted Option Consideration shall vest and become payable 50% upon the date that closing occurs pursuant to the Merger Agreement (the "Closing Date") and 50% upon the date that is nine months following the Closing Date and (ii) in the event that the holder of a Converted Option experiences an Involuntary Termination (as defined in the Merger Agreement) following the Closing Date but prior to the date that is nine months following the Closing Date, such holder's Converted Option Consideration shall immediately vest and become payable without any further action on the part of Parent or any other person.

	/s/ Rodney Young	03/05/2026
	** Signature of Reporting Person	Date
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FAQ

What happened to the RAPT (RAPT) CFO’s shares in the GSK acquisition?

The CFO’s common stock was tendered for cash at $58.00 per share. This occurred when GlaxoSmithKline LLC completed its tender offer and merger, making RAPT an indirect wholly owned subsidiary and cashing out existing common shareholders.

How were RAPT (RAPT) stock options treated for executives in the GSK deal?

All outstanding stock options became fully vested immediately before the merger’s effective time. In-the-money options were then cancelled and converted into a right to receive cash equal to the number of option shares multiplied by the excess of the $58.00 offer price over the exercise price.

What are the ‘Converted Options’ mentioned for RAPT (RAPT) in the merger?

Unvested options granted after March 1, 2025 were cancelled and replaced with cash-based GSK awards called Converted Options. These retain similar vesting terms but pay 50% at closing and 50% nine months later, with full acceleration if the holder suffers an involuntary termination in that period.

Did the RAPT (RAPT) CFO sell shares on the open market in this Form 4?

No, the Form 4 reflects dispositions to the issuer and tender offer consideration under the merger agreement. The CFO’s common shares and stock options were cashed out or converted as part of the GSK acquisition mechanics, rather than through discretionary open-market sales.

How did the RAPT (RAPT) reverse stock split affect the CFO’s reported holdings?

The number of shares and options reported was adjusted for a 1-for-8 reverse stock split effective June 16, 2025. Footnotes specify that both common shares and option grant details were restated to reflect this split when disclosing the transactions tied to the GSK merger.

What cash consideration did RAPT (RAPT) shareholders receive in the GSK transaction?

Shareholders received $58.00 in cash for each share of RAPT common stock. The tender offer by a GlaxoSmithKline LLC subsidiary acquired all outstanding shares, followed by a merger that made RAPT an indirect wholly owned subsidiary, fully cashing out prior equity holders.