ADAR1, Daniel Schneeberger disclose 727,481 shares in LeonaBio (ATHA)

Rhea-AI Filing Summary

LeonaBio, Inc. Schedule 13G reports that ADAR1 Capital Management, LLC and Daniel Schneeberger beneficially own 727,481 shares of common stock, representing 7.7% of the 9,393,514 shares outstanding as of March 31, 2026. The filing states these holdings include 568,234 shares held by ADAR1 Partners, LP, 77,371 shares held by Spearhead Insurance Solutions IDF, LLC and 81,876 shares held by separately managed accounts.

The filing also notes 1,230,315 shares underlying common warrants are excluded from the reported beneficial ownership because their exercise or exchange is subject to a 4.99% beneficial ownership limitation. ADAR1 Capital Management is disclosed as the investment manager/sub-advisor and Mr. Schneeberger is reported as a control person for the same holdings.

Insights

Securities Lawyer

Filing reports passive beneficial ownership with warrant limitations.

The Schedule 13G shows ADAR1 Capital Management and Daniel Schneeberger beneficially own 727,481 shares (7.7%) as of March 31, 2026, based on the issuer's stated outstanding share count. The filing incorporates cover-page figures and discloses manager/sub-advisor relationships.

It explicitly excludes 1,230,315 shares underlying common warrants because their exercise/exchange is subject to a 4.99% beneficial ownership limitation. Disclosure of the limitation is material to how much the holders could convert without breaching the cap.

Institutional Investor Analyst

ADAR1 and its manager hold a concentrated ~7.7% position; warrants create capped potential upside.

The filing breaks down holdings by vehicle: ADAR1 Partners, LP (568,234), Spearhead Insurance Solutions IDF, LLC (77,371) and other separately managed accounts (81,876). The manager is reported to have indirect beneficial ownership through those entities.

Because 1,230,315 warrant shares are excluded and subject to a 4.99% cap, any future conversion would be limited; further filings would be required to show conversion activity or changes in percentage ownership.

Key Figures

Reported shares beneficially owned: 727,481 shares Percent of class: 7.7% Shares outstanding used: 9,393,514 shares +4 more

7 metrics

Reported shares beneficially owned 727,481 shares Beneficial ownership reported by ADAR1 and Daniel Schneeberger

Percent of class 7.7% Based on outstanding shares as of <date>March 31, 2026</date>

Shares outstanding used 9,393,514 shares Issuer's Form 10-Q for quarter ended <date>March 31, 2026</date>

Warrants excluded 1,230,315 shares Common warrants excluded from beneficial ownership due to limitation

ADAR1 Partners holding 568,234 shares Held by ADAR1 Partners, LP as disclosed in filing

Spearhead Insurance holding 77,371 shares Held by Spearhead Insurance Solutions IDF, LLC as disclosed

Separately managed accounts holding 81,876 shares Held by other separately managed accounts as of March 31, 2026

Key Terms

beneficial ownership limitation, common warrants, indirect beneficially own

3 terms

beneficial ownership limitation regulatory

"the exchange and exercise of which are subject to 4.99% beneficial ownership limitations"

A beneficial ownership limitation is a rule that caps the percentage of a company’s shares an investor can be treated as owning or controlling for voting, regulatory or tax purposes. It matters to investors because it can restrict how many shares a person or group can buy or vote, affect takeover chances, and influence share liquidity and value — like a speed limit that prevents any single driver from taking over the whole road.

common warrants financial

"Excludes 1,230,315 shares of Common Stock underlying common warrants held by ADAR1 Partners, LP"

A common warrant is a tradable instrument that gives its holder the right to buy a company’s common shares at a fixed price within a set time period, similar to a coupon that can be redeemed later to purchase stock. Investors care because exercising warrants can boost potential gains if the stock rises, but it can also dilute existing shareholders by increasing the number of shares outstanding, which can lower per-share value.

indirect beneficially own regulatory

"may be deemed to indirectly beneficially own securities held by ADAR1 Partners, LP"

SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

SCHEDULE 13G

UNDER THE SECURITIES EXCHANGE ACT OF 1934

LeonaBio, Inc.

(Name of Issuer)

Common Stock, $0.0001 par value per share

(Title of Class of Securities)

04746L203

(CUSIP Number)

03/31/2026

(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): 04746L203

1

Names of Reporting Persons

ADAR1 Capital Management, LLC

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

TEXAS

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 0.00
6	Shared Voting Power 727,481.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 727,481.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

727,481.00

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)

7.7 %

12

Type of Reporting Person (See Instructions)

IA, OO

Comment for Type of Reporting Person: Includes (i) 568,234 shares of common stock, $0.0001 par value per share ("Common Stock") held by ADAR1 Partners, LP, (ii) 77,371 shares of Common Stock held by Spearhead Insurance Solutions IDF, LLC and (iii) 81,876 shares of Common Stock held by other separately managed accounts as of March 31, 2026. Excludes 1,230,315 shares of Common Stock underlying common warrants held by ADAR1 Partners, LP and Spearhead Insurance Solutions IDF, LLC, the exchange and exercise of which are subject to 4.99% beneficial ownership limitations. As the investment manager of ADAR1 Partners, LP and as the sub-advisor of Spearhead Insurance Solutions IDF, LLC and the separately managed accounts referenced above, ADAR1 Capital Management, LLC may be deemed to indirectly beneficially own securities held by ADAR1 Partners, LP, Spearhead Insurance Solutions IDF, LLC and the separately managed accounts. Based on 9,393,514 shares of Common Stock of LeonaBio, Inc. (the "Issuer") outstanding as of March 31, 2026, reported in the Issuer's Form 10-Q for the quarterly period ended March 31, 2026, filed with the Securities and Exchange Commission on May 7, 2026.

SCHEDULE 13G

CUSIP Number(s): 04746L203

1

Names of Reporting Persons

Daniel Schneeberger

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

SWITZERLAND

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 0.00
6	Shared Voting Power 727,481.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 727,481.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

727,481.00

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)

7.7 %

12

Type of Reporting Person (See Instructions)

HC, IN

Comment for Type of Reporting Person: Includes (i) 568,234 shares of common stock, $0.0001 par value per share ("Common Stock") held by ADAR1 Partners, LP, (ii) 77,371 shares of Common Stock held by Spearhead Insurance Solutions IDF, LLC and (iii) 81,876 shares of Common Stock held by other separately managed accounts as of March 31, 2026. Excludes 1,230,315 shares of Common Stock underlying common warrants held by ADAR1 Partners, LP and Spearhead Insurance Solutions IDF, LLC, the exchange and exercise of which are subject to 4.99% beneficial ownership limitations. As the manager of ADAR1 Capital Management, LLC, Mr. Schneeberger may be deemed to indirectly beneficially own securities held by ADAR1 Partners, LP, Spearhead Insurance Solutions IDF, LLC and the separately managed accounts referenced above. Based on 9,393,514 shares of Common Stock of LeonaBio, Inc. (the "Issuer") outstanding as of March 31, 2026, reported in the Issuer's Form 10-Q for the quarterly period ended March 31, 2026, filed with the Securities and Exchange Commission on May 7, 2026.

SCHEDULE 13G

Item 1.
(a)	Name of issuer: LeonaBio, Inc.
(b)	Address of issuer's principal executive offices: 18706 North Creek Parkway Suite 104 Bothell, WA, 98011
Item 2.
(a)	Name of person filing: This Schedule is being filed on behalf of each of the following persons (each, a "Reporting Person" and collectively, the "Reporting Persons"): (i) ADAR1 Capital Management, LLC ("ADAR1 Capital Management"); and (ii) Daniel Schneeberger ("Mr. Schneeberger").
(b)	Address or principal business office or, if none, residence: The address of the principal business office of each of the Reporting Persons is 3503 Wild Cherry Drive, Building 9, Austin, Texas 78738.
(c)	Citizenship: (i) ADAR1 Capital Management is a Texas limited liability company; and (ii) Mr. Schneeberger is a citizen of Switzerland.
(d)	Title of class of securities: Common Stock, $0.0001 par value per share
(e)	CUSIP Number(s): 04746L203
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: The information contained on the cover pages of this Schedule 13G is incorporated herein by reference.
(b)	Percent of class: The information contained on the cover pages of this Schedule 13G is incorporated herein by reference.
(c)	Number of shares as to which the person has:
	(i) Sole power to vote or to direct the vote: The information contained on the cover pages of this Schedule 13G is incorporated herein by reference.
	(ii) Shared power to vote or to direct the vote: The information contained on the cover pages of this Schedule 13G is incorporated herein by reference.
	(iii) Sole power to dispose or to direct the disposition of: The information contained on the cover pages of this Schedule 13G is incorporated herein by reference.
	(iv) Shared power to dispose or to direct the disposition of: The information contained on the cover pages of this Schedule 13G is incorporated herein by reference.
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.
	If a parent holding company has filed this schedule, pursuant to Rule 13d-1(b)(ii)(G), so indicate under Item 3(g) and attach an exhibit stating the identity and the Item 3 classification of the relevant subsidiary. If a parent holding company has filed this schedule pursuant to Rule 13d-1(c) or Rule 13d-1(d), attach an exhibit stating the identification of the relevant subsidiary. Mr. Schneeberger is filing this Schedule 13G as a control person in respect of shares beneficially owned by ADAR1 Capital Management, an investment adviser as described in SS 240.13d-1(b)(1)(ii)(E).
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.

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.

ADAR1 Capital Management, LLC

Signature:	/s/ Daniel Schneeberger
Name/Title:	Daniel Schneeberger, Manager
Date:	05/15/2026

Daniel Schneeberger

Signature:	/s/ Daniel Schneeberger
Name/Title:	Daniel Schneeberger, in his individual capacity
Date:	05/15/2026

Exhibit Information

Exhibit A: Joint Filing Agreement

FAQ

What stake does ADAR1 report in LeonaBio (ATHA)?

ADAR1 reports 727,481 shares, equal to 7.7% of LeonaBio's common stock based on 9,393,514 shares outstanding as of March 31, 2026. The figure aggregates holdings across several managed vehicles and accounts.

Does the filing include warrants in the ownership percentage for ATHA?

No. The filing excludes 1,230,315 shares underlying common warrants because their exercise/exchange is subject to a 4.99% beneficial ownership limitation, so those warrants are not counted in the 7.7%.

Who is Daniel Schneeberger in the Schedule 13G for ATHA?

Mr. Schneeberger is identified as manager and control person related to ADAR1 Capital Management and is reported to indirectly beneficially own the same 727,481 shares through ADAR1-managed entities and accounts.

What is the as-of date used to calculate ATHA ownership percentages?

The ownership percentage is calculated using 9,393,514 shares outstanding as of March 31, 2026, per the issuer's Form 10-Q for the quarter ended March 31, 2026, referenced in the filing.

Are there limits on future conversion of warrants held by ADAR1 for ATHA?

Yes. The filing states that the 1,230,315 warrant shares are subject to a 4.99% beneficial ownership limitation, which constrains exchange or exercise that would increase beneficial ownership above that cap.