Rein Therapeutics director buys shares, gets options

Rein Therapeutics, Inc. director and officer James Brian Windsor reported both a stock purchase and a new option grant.

Rhea-AI Filing Summary

Rein Therapeutics, Inc. director and officer James Brian Windsor reported both a stock purchase and a new option grant. On April 30, 2026, he bought 25,000 shares of common stock at $1.00 per share in the company’s follow-on public offering, bringing his direct common stock holdings to 27,046 shares.

On May 8, 2026, he received a stock option covering 150,000 shares of common stock at an exercise price of $1.17 per share, expiring on May 8, 2036. Twenty-five percent of the option is scheduled to vest on May 8, 2027, with the remainder vesting in equal monthly installments through May 8, 2031.

Insider Trade Summary

Net Buyer: 25,000 shares

Net Buy 2 txns

Insider WINDSOR JAMES BRIAN

Role See Remarks

Bought 25,000 shs ($25K)

Type	Security	Shares	Price	Value
Grant/Award	Stock Option (Right to Buy)	150,000	$0.00	$0.00
Purchase	Common stock , $0.001 par value	25,000	$1.00	$25K

Holdings After Transaction: Stock Option (Right to Buy) — 150,000 contracts (Direct); Common stock , $0.001 par value — 27,046 shares (Direct)

Footnotes (2)

1. F1. Shares purchased in Issuer's April 30, 2026 follow-on public offering.
2. F2. This option was granted on May 8, 2026. The 25% of the shares underlying the option are scheduled to vest on May 8, 2027 and thereafter in equal monthly installments through May 8, 2031.

Key Figures

Common shares purchased: 25,000 shares at $1.00 Common shares held after purchase: 27,046 shares Option grant size: 150,000 shares +3 more

6 metrics

Common shares purchased 25,000 shares at $1.00 Open-market/offer purchase on April 30, 2026

Common shares held after purchase 27,046 shares Direct ownership after April 30, 2026 transaction

Option grant size 150,000 shares Stock option granted May 8, 2026

Option exercise price $1.17 per share Exercise price for 150,000-share option

Option expiration May 8, 2036 Expiry date of stock option grant

Initial cliff vesting 25% on May 8, 2027 First vesting milestone for option

Key Terms

follow-on public offering, Stock Option (Right to Buy), exercise price, vesting

4 terms

follow-on public offering financial

"Shares purchased in Issuer's April 30, 2026 follow-on public offering."

An offering of new shares by a company that has already gone public, sold to investors to raise additional cash. Like a bakery cutting a larger cake to serve more customers, it increases the number of shares available which can lower each existing share’s claim on profits and ownership; investors watch these offerings because they can dilute current holdings, signal fundraising needs or growth plans, and often affect the stock price in the short term.

Stock Option (Right to Buy) financial

"security_title: Stock Option (Right to Buy)"

exercise price financial

"conversion_or_exercise_price: 1.1700"

The exercise price is the fixed amount at which you can buy or sell an asset, like a stock, when using an options contract. It matters because it helps determine whether exercising the option will be profitable or not, depending on the current market price. Think of it as the set price you agree on today to buy or sell later.

vesting financial

"shares underlying the option are scheduled to vest on May 8, 2027 and thereafter in equal monthly installments"

Vesting is the process by which you earn full ownership of something, like company stock or a retirement benefit, over time. It’s like earning the right to keep a gift piece by piece the longer you stay with a company, making sure employees stay committed before they receive all the benefits.

FAQ

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

What insider transactions did Rein Therapeutics (RNTX) report for James Brian Windsor?

Rein Therapeutics reported that director and officer James Brian Windsor bought 25,000 common shares at $1.00 each and received a stock option for 150,000 shares at a $1.17 exercise price, both increasing his direct economic exposure to the company.

At what price did the Rein Therapeutics (RNTX) insider buy common stock?

James Brian Windsor purchased 25,000 Rein Therapeutics common shares at $1.00 per share. The footnote states these shares were bought in the company’s April 30, 2026 follow-on public offering, indicating participation in a capital-raising transaction rather than a secondary market trade.

What are the key terms of the Rein Therapeutics (RNTX) stock option granted to James Brian Windsor?

Windsor received a stock option for 150,000 Rein Therapeutics common shares at a $1.17 exercise price. The option was granted May 8, 2026, expires May 8, 2036, and vests 25% on May 8, 2027, with remaining shares vesting monthly through May 8, 2031.

How many Rein Therapeutics (RNTX) shares does James Brian Windsor hold after these transactions?

Following the reported purchase, Windsor directly holds 27,046 shares of Rein Therapeutics common stock. In addition, he holds an option covering 150,000 underlying common shares, which provides potential future ownership if he exercises at the $1.17 strike price.

How does the vesting schedule work for the Rein Therapeutics (RNTX) option grant?

The option vests over several years. Twenty-five percent of the 150,000 shares is scheduled to vest on May 8, 2027. The remaining 75% vests in equal monthly installments through May 8, 2031, aligning Windsor’s incentives with longer-term company performance.

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

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Accepted by SEC EDGAR 05/13/2026 - 08:47 AM EDT Learn about SEC filing dates

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^*

WINDSOR JAMES BRIAN

(Last) (First) (Middle)

12407 N. MOPAC EXPY. SUITE 250 #390

(Street)

AUSTIN TEXAS 78758

(City) (State) (Zip)

UNITED STATES

(Country)

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

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

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

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
04/30/2026

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 , $0.001 par value	04/30/2026		P		25,000(1)	A	$1	27,046	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
Stock Option (Right to Buy)	$1.17	05/08/2026		A			150,000	(2)	05/08/2036	Common Stock	150,000	$0.00	150,000	D

Explanation of Responses:

1. Shares purchased in Issuer's April 30, 2026 follow-on public offering.

2. This option was granted on May 8, 2026. The 25% of the shares underlying the option are scheduled to vest on May 8, 2027 and thereafter in equal monthly installments through May 8, 2031.

Remarks:

President and Chief Executive Officer

	/s/ Brian Windsor, Ph.D.	05/12/2026
	** 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)