KPTI: T. Rowe Price reports 6.6% stake

THERAPEUTICS INC group T. Rowe Price Investment Management, Inc. filed an amended Schedule 13G/A reporting beneficial ownership of 1,539,147 shares, representing 6.6% of the outstanding common stock as disclosed in the filing.

Rhea-AI Filing Summary

THERAPEUTICS INC group T. Rowe Price Investment Management, Inc. filed an amended Schedule 13G/A reporting beneficial ownership of 1,539,147 shares, representing 6.6% of the outstanding common stock as disclosed in the filing. The filer reports sole power to vote and sole power to dispose over 786,135 shares. The filing is signed and dated 06/05/2026.

Insights

Institutional Ownership Analyst

Large passive holding disclosed: 1.54M shares, 6.6% stake.

The filing lists 1,539,147 shares as beneficially owned and reports 786,135 shares under sole voting and dispositive power. This indicates a meaningful institutional position in the issuer as of the filing dates.

Holder disclosures like this help trace potential shareholder influence; timing and any trading intent are not stated in the excerpt.

Securities Compliance Specialist

Amendment confirms reporting obligations were updated and includes an assertion denying beneficial ownership.

The filing is an Amendment No. 3 to a Schedule 13G and contains a declarative statement denying beneficial ownership by the filer. Such language is common when an investment manager files in a fiduciary capacity.

Regulatory impact is procedural; cash‑flow or disposition plans are not disclosed in the provided excerpt.

Key Figures

Beneficially owned: 1,539,147 shares Percent of class: 6.6% Sole voting power: 786,135 shares +1 more

4 metrics

Beneficially owned 1,539,147 shares Schedule 13G/A ownership section

Percent of class 6.6% Percent of class as reported in Item 4

Sole voting power 786,135 shares Item 4(i) sole power to vote

Sole dispositive power 786,135 shares Item 4(iii) sole power to dispose

Key Terms

Schedule 13G/A, Beneficial ownership, Sole dispositive power

3 terms

Schedule 13G/A regulatory

"Amendment No. 3 ) THERAPEUTICS INC COMMON STOCK"

A Schedule 13G/A is an amended public filing with the U.S. securities regulator that updates a previous Schedule 13G, disclosing when an individual or group holds a substantial (typically over 5%) stake in a company and is claiming a passive, non‑controlling intent. Investors monitor these updates because rising or falling holdings can signal changing confidence, potential future moves, or shifts in voting power — like watching a public ledger where large shareholders quietly adjust their positions.

Beneficial ownership regulatory

"Item 4. | Ownership (a) | Amount beneficially owned: 1539147"

Beneficial ownership means the person or entity that actually enjoys the benefits of owning shares or other assets — such as receiving dividends, voting rights, or price gains — even if the legal title is held in another name. For investors it matters because knowing who truly controls and profits from a company reveals who can influence decisions, exposes potential conflicts of interest or hidden concentration of power, and affects transparency and risk in the stock.

Sole dispositive power regulatory

"Sole power to dispose or to direct the disposition of: 786135"

Sole dispositive power is the exclusive legal authority to decide what happens to a security — for example, whether to sell, transfer, or retain shares — without needing anyone else’s permission. Investors care because it signals who truly controls the economic outcome of an investment: like holding the only key to a safe, the holder can realize gains or losses and may trigger regulatory reporting, insider rules, or influence over corporate ownership.

FAQ

AI-generated questions and answers. How Rhea-AI works. Not financial advice.

What stake does T. Rowe Price report in THERAPEUTICS INC (KPTI)?

The filer reports beneficial ownership of 1,539,147 shares, equal to 6.6% of the common stock. The Schedule 13G/A shows the size and percent directly in the ownership section of the filing.

How many shares does T. Rowe Price have voting and dispositive power over?

786,135 shares are reported as both sole voting power and sole dispositive power. Those counts appear in the filing's breakdown of voting and dispositive authority for the reported position.

When was the Schedule 13G/A amendment signed for KPTI?

The amendment is signed and dated 06/05/2026 by Ellen York, Vice President. The cover references 05/31/2026 as an associated date in the header of the filing excerpt.

Does the filing state that T. Rowe Price is the beneficial owner?

The filing includes a statement where T. Rowe Price Investment Management, Inc. denies beneficial ownership of the securities, asserting the filing should not be construed as admission of beneficial ownership.

AI-generated analysis. How Rhea-AI works. Not financial advice.

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Accepted by SEC EDGAR 06/05/2026 - 11:43 AM EDT Learn about SEC filing dates

SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

SCHEDULE 13G

UNDER THE SECURITIES EXCHANGE ACT OF 1934

(Amendment No. 3)

KARYOPHARM THERAPEUTICS INC

(Name of Issuer)

COMMON STOCK

(Title of Class of Securities)

48576U205

(CUSIP Number)

05/31/2026

(Date of Event Which Requires Filing of this Statement)

Check the appropriate box to designate the rule pursuant to which this Schedule is filed:

Rule 13d-1(b)

Rule 13d-1(c)

Rule 13d-1(d)

schemaVersion:

SCHEDULE 13G

CUSIP Number(s): 48576U205

1

Names of Reporting Persons

T. Rowe Price Investment Management, Inc.

2

Check the appropriate box if a member of a Group (see instructions)

(a)
(b)

3

Sec Use Only

4

Citizenship or Place of Organization

MARYLAND

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 786,135.00
6	Shared Voting Power 0.00
7	Sole Dispositive Power 786,135.00
8	Shared Dispositive Power 0.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

1,539,147.00

10

Check box if the aggregate amount in row (9) excludes certain shares (See Instructions)

11

Percent of class represented by amount in row (9)

6.6 %

12

Type of Reporting Person (See Instructions)

IA

SCHEDULE 13G

Item 1.
(a)	Name of issuer: KARYOPHARM THERAPEUTICS INC
(b)	Address of issuer's principal executive offices: 85 WELLS AVENUE, SECOND FLOOR, NEWTON, MA, 02459
Item 2.
(a)	Name of person filing: T. Rowe Price Investment Management, Inc.
(b)	Address or principal business office or, if none, residence: 1307 Point Street, Baltimore, MD 21231
(c)	Citizenship: Maryland
(d)	Title of class of securities: COMMON STOCK
(e)	CUSIP No.: 48576U205
Item 3.	If this statement is filed pursuant to §§ 240.13d-1(b) or 240.13d-2(b) or (c), check whether the person filing is a:
(a)	Broker or dealer registered under section 15 of the Act (15 U.S.C. 78o);
(b)	Bank as defined in section 3(a)(6) of the Act (15 U.S.C. 78c);
(c)	Insurance company as defined in section 3(a)(19) of the Act (15 U.S.C. 78c);
(d)	Investment company registered under section 8 of the Investment Company Act of 1940 (15 U.S.C. 80a-8);
(e)	An investment adviser in accordance with § 240.13d-1(b)(1)(ii)(E);
(f)	An employee benefit plan or endowment fund in accordance with § 240.13d-1(b)(1)(ii)(F);
(g)	A parent holding company or control person in accordance with § 240.13d-1(b)(1)(ii)(G);
(h)	A savings associations as defined in Section 3(b) of the Federal Deposit Insurance Act (12 U.S.C. 1813);
(i)	A church plan that is excluded from the definition of an investment company under section 3(c)(14) of the Investment Company Act of 1940 (15 U.S.C. 80a-3);
(j)	A non-U.S. institution in accordance with § 240.13d-1(b)(1)(ii)(J). If filing as a non-U.S. institution in accordance with § 240.13d-1(b)(1)(ii)(J), please specify the type of institution:
(k)	Group, in accordance with Rule 240.13d-1(b)(1)(ii)(K).
Item 4.	Ownership
(a)	Amount beneficially owned: 1539147
(b)	Percent of class: 6.6 %
(c)	Number of shares as to which the person has:
	(i) Sole power to vote or to direct the vote: 786135
	(ii) Shared power to vote or to direct the vote: 0
	(iii) Sole power to dispose or to direct the disposition of: 786135
	(iv) Shared power to dispose or to direct the disposition of: 0
Item 5.	Ownership of 5 Percent or Less of a Class.
	Not Applicable
Item 6.	Ownership of more than 5 Percent on Behalf of Another Person.
	Not Applicable
Item 7.	Identification and Classification of the Subsidiary Which Acquired the Security Being Reported on by the Parent Holding Company or Control Person.
	Not Applicable
Item 8.	Identification and Classification of Members of the Group.
	Not Applicable
Item 9.	Notice of Dissolution of Group.
	Not Applicable

Item 10.

Certifications:

By signing below I certify that, to the best of my knowledge and belief, the securities referred to above were acquired and are held in the ordinary course of business and were not acquired and are not held for the purpose of or with the effect of changing or influencing the control of the issuer of the securities and were not acquired and are not held in connection with or as a participant in any transaction having that purpose or effect, other than activities solely in connection with a nomination under § 240.14a-11. T. Rowe Price Investment Management, Inc. hereby declares and affirms that the filing of Schedule 13G shall not be construed as an admission that Price Investment Management is the beneficial owner of the securities referred to, which beneficial ownership is expressly denied.

SIGNATURE

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

T. Rowe Price Investment Management, Inc.

Signature:	Ellen York
Name/Title:	Vice President
Date:	06/05/2026