Rein Therapeutics (RNTX): Lynwood group reports 5.0% ownership position

Rhea-AI Filing Summary

Lynwood Capital Management Inc., Ben Shapiro and Lynwood Opportunities Master Fund reported beneficial ownership of 4,280,500 shares of Rein Therapeutics, Inc. common stock, representing 5.0% of the class. The shares are directly held by the Fund, with the Investment Manager and Mr. Shapiro deemed beneficial owners through control of the Fund.

The ownership percentages are based on 85,539,032 shares of common stock outstanding as of May 21, 2026. Each reporting person has sole voting and dispositive power over the 4,280,500 shares and disclaims beneficial ownership of any other shares.

Key Figures

Beneficial ownership: 4,280,500 shares Ownership percentage: 5.0% Shares outstanding: 85,539,032 shares +2 more

5 metrics

Beneficial ownership 4,280,500 shares Shares of Rein Therapeutics common stock beneficially owned by each reporting person

Ownership percentage 5.0% Percentage of Rein Therapeutics common stock class beneficially owned

Shares outstanding 85,539,032 shares Rein Therapeutics common stock outstanding as of May 21, 2026

Sole voting power 4,280,500 shares Shares over which each reporting person has sole voting power

Sole dispositive power 4,280,500 shares Shares over which each reporting person has sole dispositive power

Key Terms

beneficial ownership, sole voting power, sole dispositive power, Schedule 13G, +1 more

5 terms

beneficial ownership financial

"The Fund directly beneficially owns the Common Stock reported in this Statement."

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 voting power financial

"5 | Sole Voting Power 4,280,500.00 6 | Shared Voting Power 0.00"

Sole voting power is the exclusive right to cast votes attached to a shareholder’s stock without needing approval from anyone else. Like holding the only remote control for a TV, it lets that holder decide corporate matters such as board members, mergers, and policy changes, making it important to investors because it concentrates control and can strongly influence a company’s strategy and the value of its shares.

sole dispositive power financial

"7 | Sole Dispositive Power 4,280,500.00 8 | Shared Dispositive Power 0.00"

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.

Schedule 13G regulatory

"The percentages of beneficial ownership contained herein are based on 85,539,032 shares of Common Stock outstanding"

A Schedule 13G is a formal document that investors file with the government when they acquire a large ownership stake in a company, usually for investment purposes rather than control. It helps keep the public informed about who owns significant parts of a company's shares, which can influence how the company is managed and how investors make decisions. Filing this schedule is important for transparency and understanding the ownership landscape of publicly traded companies.

CUSIP No. financial

"(d) | Title of class of securities: Common Stock, $0.001 par value per share (e) | CUSIP No.: 00887A204"

FAQ

What percentage of Rein Therapeutics (RNTX) does Lynwood report owning?

Lynwood and related reporting persons report owning 5.0% of Rein Therapeutics’ common stock. This is based on 4,280,500 shares held versus 85,539,032 shares outstanding as of May 21, 2026.

How many Rein Therapeutics (RNTX) shares are beneficially owned by the Lynwood entities?

The reporting persons beneficially own 4,280,500 shares of Rein Therapeutics common stock. These shares are directly held by Lynwood Opportunities Master Fund, with Lynwood Capital Management Inc. and Ben Shapiro deemed beneficial owners through control relationships.

Who are the reporting persons in this Schedule 13G/A for Rein Therapeutics (RNTX)?

The reporting persons are Lynwood Capital Management Inc., Ben Shapiro, and Lynwood Opportunities Master Fund. The Fund directly owns the shares; the Investment Manager and Mr. Shapiro may be deemed beneficial owners through their control of the Fund.

What voting and dispositive powers do the Lynwood entities report over Rein Therapeutics (RNTX) shares?

Each reporting person reports sole voting power and sole dispositive power over 4,280,500 Rein Therapeutics shares, with no shared voting or dispositive power disclosed in the filing.

On what share count is Lynwood’s 5.0% ownership of Rein Therapeutics (RNTX) based?

The reported 5.0% beneficial ownership is based on 85,539,032 Rein Therapeutics common shares outstanding as of May 21, 2026, as reported by the issuer in a Schedule 14A filed June 8, 2026.

Where are the Lynwood Opportunities Master Fund and Investment Manager for Rein Therapeutics (RNTX) organized?

Lynwood Opportunities Master Fund is organized in the Cayman Islands, and Lynwood Capital Management Inc. is an Ontario corporation. Ben Shapiro’s citizenship is at the federal level of Canada.

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

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Available on EDGAR 08/14/2026 - 04:15 PM Accepted by SEC EDGAR 08/14/2026 - 04:07 PM Learn about SEC filing dates

SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

SCHEDULE 13G

UNDER THE SECURITIES EXCHANGE ACT OF 1934

(Amendment No. 1)

Rein Therapeutics, Inc.

(Name of Issuer)

Common Stock, $0.001 par value per share

(Title of Class of Securities)

00887A204

(CUSIP Number)

06/30/2026

(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): 00887A204

1

Names of Reporting Persons

Lynwood Capital 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

ONTARIO, CANADA

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 4,280,500.00
6	Shared Voting Power 0.00
7	Sole Dispositive Power 4,280,500.00
8	Shared Dispositive Power 0.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

4,280,500.00

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)

5.0 %

12

Type of Reporting Person (See Instructions)

CO

SCHEDULE 13G

CUSIP Number(s): 00887A204

1

Names of Reporting Persons

Ben Shapiro

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

CANADA (FEDERAL LEVEL)

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 4,280,500.00
6	Shared Voting Power 0.00
7	Sole Dispositive Power 4,280,500.00
8	Shared Dispositive Power 0.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

4,280,500.00

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)

5.0 %

12

Type of Reporting Person (See Instructions)

IN

SCHEDULE 13G

CUSIP Number(s): 00887A204

1

Names of Reporting Persons

Lynwood Opportunities Master Fund

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

CAYMAN ISLANDS

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 4,280,500.00
6	Shared Voting Power 0.00
7	Sole Dispositive Power 4,280,500.00
8	Shared Dispositive Power 0.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

4,280,500.00

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)

5.0 %

12

Type of Reporting Person (See Instructions)

OO

SCHEDULE 13G

Item 1.
(a)	Name of issuer: Rein Therapeutics, Inc.
(b)	Address of issuer's principal executive offices: 12407 N. Mopac Expy., Suite 250, #390, Austin, TX 78758
Item 2.
(a)	Name of person filing: This Schedule 13G (this "Statement" or this "Schedule 13G") is being filed by: (1) Lynwood Capital Management Inc., an Ontario corporation (the "Investment Manager"); (2) Ben Shapiro ("Mr. Shapiro"); and (3) Lynwood Opportunities Master Fund, a Cayman Islands entity (the "Fund") (all of the foregoing, collectively, the "Reporting Persons"). The Fund is an investment vehicle. The Fund directly beneficially owns the Common Stock (as defined below) reported in this Statement. The Investment Manager is the investment manager of the Fund. Mr. Shapiro is the President, Chief Executive Officer, Chief Investment Officer, sole director and indirect controlling stockholder of the Investment Manager. Mr. Shapiro and the Investment Manager may be deemed to beneficially own the Common Stock directly beneficially owned by the Fund. Each Reporting Person disclaims beneficial ownership with respect to any Common Stock other than the Common Stock directly beneficially owned by such Reporting Person.
(b)	Address or principal business office or, if none, residence: The principal business office of the Fund is FG Services Limited, Suite 2206, Cassia Court, 72 Market Street, Camana Bay, P.O. Box 30869, Grand Cayman KY1-1204, Cayman Islands. The principal business office of the Investment Manager and Mr. Shapiro is 200 Bay St, Suite 1304, Royal Bank Plaza, South Tower, Toronto, Ontario M5J 2J1.
(c)	Citizenship: For citizenship or place of organization see Item 4 of the cover page of each Reporting Person.
(d)	Title of class of securities: Common Stock, $0.001 par value per share
(e)	CUSIP No.: 00887A204
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: See Item 9 on the cover page for each Reporting Person, and Item 2, which information is given as of the close of business on June 30, 2026, the Date of Event which requires the filing of this Schedule 13G.
(b)	Percent of class: See Item 11 on the cover page for each Reporting Person. The percentages of beneficial ownership contained herein are based on 85,539,032 shares of Common Stock outstanding as of May 21, 2026, as reported by the Issuer in a Schedule 14A filed with the SEC on June 8, 2026.
(c)	Number of shares as to which the person has:
	(i) Sole power to vote or to direct the vote: See Item 5 on the cover page for each Reporting Person.
	(ii) Shared power to vote or to direct the vote: See Item 6 on the cover page for each Reporting Person.
	(iii) Sole power to dispose or to direct the disposition of: See Item 7 on the cover page for each Reporting Person.
	(iv) Shared power to dispose or to direct the disposition of: See Item 8 on the cover page for each Reporting Person.
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 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.

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.

Lynwood Capital Management Inc.

Signature:	/s/ Ben Shapiro
Name/Title:	Ben Shapiro / Authorized Signatory
Date:	08/14/2026

Ben Shapiro

Signature:	/s/ Ben Shapiro
Name/Title:	N/A
Date:	08/14/2026

Lynwood Opportunities Master Fund

Signature:	/s/ Ben Shapiro
Name/Title:	Ben Shapiro / Authorized Signatory
Date:	08/14/2026