Tax-withholding stock sale by Karyopharm (KPTI) EVP Poulton Stuart

Rhea-AI Filing Summary

Karyopharm Therapeutics EVP and Chief Development Officer Poulton Stuart reported an automatic sale of company stock. On February 17, 2026, a broker-assisted transaction sold 378 shares of common stock at $8.63 per share to cover withholding taxes triggered by vesting restricted stock units.

The sale was executed under a durable automatic sale instruction plan adopted on May 18, 2022 and is described as non-discretionary for the insider. Following this tax-related sale, Poulton Stuart directly holds 99,429 shares of Karyopharm Therapeutics common stock.

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).

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^*

Poulton Stuart

(Last) (First) (Middle)

C/O KARYOPHARM THERAPEUTICS INC.

85 WELLS AVENUE

(Street)

NEWTON MA 02459

(City) (State) (Zip)

2. Issuer Name and Ticker or Trading Symbol
Karyopharm Therapeutics Inc. [ KPTI ]

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

	Director		10% Owner
X	Officer (give title below)		Other (specify below)
	EVP, Chief Development Officer

3. Date of Earliest Transaction (Month/Day/Year)
02/17/2026

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	02/17/2026		S(1)		378	D	$8.63	99,429	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

Explanation of Responses:

1. This transaction was effected pursuant to a durable automatic sale instruction plan adopted by the reporting person on May 18, 2022, and represents a broker-assisted sale of shares to satisfy the payment of withholding tax liability incurred upon the vesting of restricted stock units. The sale does not represent a discretionary trade by the reporting person.

	/s/ Nancy Smith as Attorney-in-Fact for Stuart Poulton	02/19/2026
	** 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.

FAQ

What insider transaction did Karyopharm Therapeutics (KPTI) report for Poulton Stuart?

Karyopharm reported that EVP and Chief Development Officer Poulton Stuart had an automatic, broker-assisted sale of 378 common shares at $8.63 per share. This sale was executed to cover withholding tax obligations from vesting restricted stock units.

Was the KPTI insider sale by Poulton Stuart a discretionary trade?

The sale was not discretionary. It was carried out under a durable automatic sale instruction plan adopted on May 18, 2022, and executed by a broker specifically to satisfy withholding tax liabilities from vesting restricted stock units, rather than a voluntary open-market decision.

How many Karyopharm (KPTI) shares did Poulton Stuart sell and at what price?

Poulton Stuart’s Form 4 shows a sale of 378 shares of Karyopharm common stock at a price of $8.63 per share. The transaction was categorized as an open-market or private sale executed by a broker to cover tax withholding obligations.

How many KPTI shares does Poulton Stuart own after this Form 4 transaction?

After the reported transaction, Poulton Stuart directly holds 99,429 shares of Karyopharm Therapeutics common stock. This figure reflects his direct ownership following the automatic broker-assisted tax-withholding sale of 378 shares on February 17, 2026.

Why did Karyopharm EVP Poulton Stuart sell shares according to the Form 4?

The Form 4 states the sale was to satisfy withholding tax liability incurred when restricted stock units vested. A broker executed the automatic sale under a pre-established plan, meaning it was a tax-management transaction rather than a discretionary portfolio decision.

What does the automatic sale instruction plan mean for this KPTI insider trade?

The automatic sale instruction plan means trades occur according to preset instructions rather than real-time decisions. For this KPTI filing, it directed a broker-assisted sale of 378 shares to cover tax withholding from RSU vesting, limiting discretionary timing by the insider.