Bruce Booth trims Kymera Therapeutics (KYMR) stake via 10b5-1 sales

Rhea-AI Filing Summary

Kymera Therapeutics director Bruce Booth reported option exercises and related share sales in Kymera Therapeutics, Inc. common stock. On April 22, 2026 he exercised options for 259 shares at $20.00 per share and 5,641 shares at $14.18 per share, then sold 5,900 shares in open‑market transactions at a weighted average price of about $89.96 per share, leaving no directly owned shares.

Entities associated with Atlas Venture made additional small sales of 12 and 88 shares at $90.08 per share. After these trades, Atlas Venture Fund X, L.P. held 674,944 shares and Atlas Venture Opportunity Fund I, L.P. held 3,899,829 shares, with Booth disclaiming Section 16 beneficial ownership except to any pecuniary interest. The filing notes these sales were made under pre‑arranged Rule 10b5‑1 trading plans adopted in December 2025.

Insights

Equity compensation and insider-trading analyst

Booth’s filing shows an option exercise-and-sell pattern and minor pre-planned fund sales.

Director Bruce Booth exercised options for 5,900 Kymera Therapeutics shares at strike prices of $20.00 and $14.18, then sold 5,900 shares around $89.96. This is a classic exercise-and-sell, converting derivative exposure into cash rather than expanding direct ownership.

Two Atlas Venture funds associated with Booth sold a combined 100 shares while retaining 674,944 and 3,899,829 shares respectively, and Booth disclaims Section 16 beneficial ownership beyond any pecuniary interest. The filing states these sales occurred under Rule 10b5‑1 trading plans adopted in December 2025, suggesting they were pre‑scheduled and more routine than discretionary market-timing moves.

Insider Trade Summary 10b5-1

Net Seller: 6,000 shares ($539,772)

Net Sell 7 txns

Insider Booth Bruce

Role null

Sold 6,000 shs ($540K)

Type	Security	Shares	Price	Value
Exercise	Stock Option (Right to Buy)	5,641	$0.00	--
Exercise	Stock Option (Right to Buy)	259	$0.00	--
Exercise	Common Stock	5,641	$14.18	$80K
Exercise	Common Stock	259	$20.00	$5K
Sale	Common Stock	5,900	$89.96	$531K
Sale	Common Stock	88	$90.08	$8K
Sale	Common Stock	12	$90.08	$1K

Holdings After Transaction: Stock Option (Right to Buy) — 0 shares (Direct, null); Common Stock — 5,641 shares (Direct, null); Common Stock — 3,899,829 shares (Indirect, See footnote)

Footnotes (1)

1. This transaction was made pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on December 16, 2025. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $89.95 to $90.02 inclusive. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold each separate price within the ranges set forth in this footnote. This transaction was made pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on December 11, 2025. These shares are held directly by Atlas Venture Fund X, L.P. ("Atlas Venture Fund X"). The general partner of Atlas Venture Fund X is Atlas Venture Associates X, L.P. ("AVA X LP"). Atlas Venture Associates X, LLC ("AVA X LLC") is the general partner of AVA X LP. The Reporting Person is a member of AVA X LLC and disclaims Section 16 beneficial ownership of the securities held by Atlas Venture Fund X, except to the extend of his pecuniary interest therein, if any. The shares are owned directly by Atlas Venture Opportunity Fund I, L.P. ("AVOF"). Atlas Venture Associates Opportunity I, L.P. ("AVAO LP") is the general partner of AVOF. Atlas Venture Associates Opportunity I, LLC ("AVAO LLC") is the general partner of AVAO LP. The Reporting Person is a member of AVAO LLC and disclaims Section 16 beneficial ownership of such securities held by AVOF, except to the extent of his pecuniary interest therein, if any. Fully vested and exercisable.

Key Figures

Direct shares sold: 5,900 shares at ~$89.96 Atlas Venture Fund X remaining stake: 674,944 shares Atlas Venture Opportunity Fund I stake: 3,899,829 shares +3 more

6 metrics

Direct shares sold 5,900 shares at ~$89.96 Open-market sale on April 22, 2026

Atlas Venture Fund X remaining stake 674,944 shares Common stock held after April 22, 2026 trades

Atlas Venture Opportunity Fund I stake 3,899,829 shares Common stock held after April 22, 2026 trades

Option exercise at $20.00 259 shares at $20.00 Stock option exercise converting into common stock

Option exercise at $14.18 5,641 shares at $14.18 Stock option exercise converting into common stock

Small Atlas Venture sales 12 and 88 shares at $90.08 Open-market sales on April 22, 2026

Key Terms

Rule 10b5-1 trading plan, Section 16 beneficial ownership, Stock Option (Right to Buy), weighted average price

4 terms

Rule 10b5-1 trading plan regulatory

"This transaction was made pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person"

A Rule 10b5-1 trading plan is a pre-arranged schedule that allows company insiders to buy or sell stock at specific times, even if they have inside information. It helps prevent accusations of unfair trading by making these transactions look planned and transparent, rather than sneaky or illegal.

Section 16 beneficial ownership regulatory

"disclaims Section 16 beneficial ownership of the securities held by Atlas Venture Fund X"

Stock Option (Right to Buy) financial

"security_title": "Stock Option (Right to Buy)""

weighted average price financial

"The price reported in Column 4 is a weighted average price."

Weighted average price is the average price of a security where each trade or component is counted according to its size, so bigger trades pull the average more than smaller ones. Think of it like calculating the average cost of a grocery haul where items you bought more of have greater influence on the final per-item cost. Investors use it to understand the true average price paid or received, judge execution quality, and compare trading performance against market movement.

Form 4 Insider Transactions: What Each Field Means →

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

OMB APPROVAL

OMB Number:			3235-0287
Estimated average burden
hours per response:			0.5

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

X

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^*

Booth Bruce

(Last) (First) (Middle)

C/O KYMERA THERAPEUTICS, INC.

500 NORTH BEACON STREET, FLOOR 4

(Street)

WATERTOWN MASSACHUSETTS 02472

(City) (State) (Zip)

UNITED STATES

(Country)

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

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

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

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
04/22/2026

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

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

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

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	04/22/2026		M		5,641	A	$14.18	5,641	D
Common Stock	04/22/2026		M		259	A	$20	5,900	D
Common Stock	04/22/2026		S(1)		5,900	D	$89.96(2)	0	D
Common Stock	04/22/2026		S(3)		88	D	$90.08	3,899,829	I	See footnote(4)
Common Stock	04/22/2026		S(3)		12	D	$90.08	674,944	I	See footnote(5)

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
Stock Option (Right to Buy)	$14.18	04/22/2026		M			5,641	(6)	06/15/2032	Common Stock	5,641	$0	0	D
Stock Option (Right to Buy)	$20	04/22/2026		M			259	(6)	08/19/2030	Common Stock	259	$0	39,868	D

Explanation of Responses:

1. This transaction was made pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on December 16, 2025.

2. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $89.95 to $90.02 inclusive. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold each separate price within the ranges set forth in this footnote.

3. This transaction was made pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on December 11, 2025.

4. These shares are held directly by Atlas Venture Fund X, L.P. ("Atlas Venture Fund X"). The general partner of Atlas Venture Fund X is Atlas Venture Associates X, L.P. ("AVA X LP"). Atlas Venture Associates X, LLC ("AVA X LLC") is the general partner of AVA X LP. The Reporting Person is a member of AVA X LLC and disclaims Section 16 beneficial ownership of the securities held by Atlas Venture Fund X, except to the extend of his pecuniary interest therein, if any.

5. The shares are owned directly by Atlas Venture Opportunity Fund I, L.P. ("AVOF"). Atlas Venture Associates Opportunity I, L.P. ("AVAO LP") is the general partner of AVOF. Atlas Venture Associates Opportunity I, LLC ("AVAO LLC") is the general partner of AVAO LP. The Reporting Person is a member of AVAO LLC and disclaims Section 16 beneficial ownership of such securities held by AVOF, except to the extent of his pecuniary interest therein, if any.

6. Fully vested and exercisable.

	/s/ Ommer Chohan, Attorney-in-Fact	04/24/2026
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* If the form is filed by more than one reporting person, see Instruction 4 (b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.
* Form 4: SEC 1474 (03-26)

FAQ

What did Kymera Therapeutics (KYMR) director Bruce Booth report in this Form 4 filing?

Bruce Booth reported exercising options for 5,900 Kymera Therapeutics shares, then selling 5,900 shares in open-market trades around $89.96 per share. The filing also shows very small sales by Atlas Venture funds that continue to hold large Kymera positions after the transactions.

How many Kymera Therapeutics (KYMR) shares did Bruce Booth sell and at what prices?

Booth sold 5,900 Kymera Therapeutics common shares in open-market transactions at a weighted average price near $89.96 per share. Two small additional sales of 12 and 88 shares occurred through Atlas Venture entities at $90.08 per share, according to the Form 4 details.

What option exercises did Bruce Booth report for Kymera Therapeutics (KYMR)?

Booth exercised stock options covering 259 Kymera shares at a $20.00 strike and 5,641 shares at a $14.18 strike. These exercises converted derivative awards into common stock, which was then followed by open-market sales totaling 5,900 shares on the same reported date.

How many Kymera Therapeutics (KYMR) shares do the Atlas Venture funds hold after the reported trades?

After the reported transactions, Atlas Venture Fund X, L.P. holds 674,944 Kymera shares, while Atlas Venture Opportunity Fund I, L.P. holds 3,899,829 shares. Booth is a member of the funds’ general partner entities and disclaims Section 16 beneficial ownership except for any pecuniary interest.

Were Bruce Booth’s Kymera Therapeutics (KYMR) share sales made under a Rule 10b5-1 plan?

Yes. Footnotes state the reported Kymera share sales were executed pursuant to Rule 10b5‑1 trading plans adopted in December 2025. Such pre-arranged plans are designed to allow insiders to sell shares on a set schedule, reducing the significance of short-term market timing.

Does Bruce Booth still directly own Kymera Therapeutics (KYMR) shares after these transactions?

Following the reported transactions, Booth’s directly held Kymera common stock position is shown as zero shares. His remaining economic exposure comes through interests in Atlas Venture funds that collectively hold several million Kymera shares, where he disclaims Section 16 beneficial ownership beyond any pecuniary interest.