Qatar Investment Authority takes 4.5% stake in Sionna Therapeutics (SION)

Rhea-AI Filing Summary

Sionna Therapeutics Inc ownership update: Qatar Investment Authority, through wholly owned Q Healthcare Holding LLC, reports beneficial ownership of 2,020,258 shares of Common Stock, representing 4.5% of the class. The Schedule 13G/A amendment identifies sole voting and dispositive power over these shares.

Insights

Institutional Ownership Analyst

QIA reports a passive 4.5% stake via a subsidiary.

Qatar Investment Authority is disclosed as the filing person and states that Q Healthcare Holding LLC (its wholly owned subsidiary) acquired and holds 2,020,258 shares with sole voting and dispositive power. The filing is an amended Schedule 13G/A.

Timing and cash‑flow treatment are not stated in the excerpt; subsequent filings would show any change in position.

Key Figures

Shares beneficially owned: 2,020,258 shares Percent of class: 4.5% CUSIP: 829401108

3 metrics

Shares beneficially owned 2,020,258 shares Beneficial ownership reported in Schedule 13G/A amendment

Percent of class 4.5% Percent of Common Stock reported in Item 4(b)

CUSIP 829401108 Identifies Common Stock class in the filing

Key Terms

Schedule 13G/A, Beneficial ownership, Sole Dispositive Power

3 terms

Schedule 13G/A regulatory

"Amendment No. 1 ) Sionna Therapeutics Inc"

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 financial

"Item 4. | Ownership (a) | Amount beneficially owned: 2,020,258"

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

"7 | Sole Dispositive Power 2,020,258.00"

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.

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

See more from StockTitan in Google Search and AI answers. Adds StockTitan as a preferred source · opens Google

Add on Google Not now

Accepted by SEC EDGAR 05/12/2026 - 07:39 AM Learn about SEC filing dates

FAQ

What stake does Qatar Investment Authority hold in Sionna Therapeutics (SION)?

Qatar Investment Authority holds 2,020,258 shares, or 4.5% of Sionna Therapeutics. The filing states sole voting and dispositive power over these shares, held via its wholly owned subsidiary Q Healthcare Holding LLC as disclosed in the Schedule 13G/A amendment.

Who is the reported holder of the SION shares?

The filing lists Qatar Investment Authority and Q Healthcare Holding LLC as holders. The Schedule 13G/A identifies Q Healthcare Holding LLC as the wholly owned subsidiary that acquired the securities and names Mohammed Fahad Al Khulaifi as signatory.

Does the filing indicate active trading or control intentions by QIA?

The Schedule 13G/A shows beneficial ownership with sole voting and dispositive power. The document does not state trading intentions, activism, or any plans to change ownership; it only reports current ownership and power over the shares.

What class of securities and CUSIP are reported in the amendment?

The filing reports Common Stock with CUSIP 829401108. The Schedule 13G/A amendment names the class as Common Stock and provides the issuer's principal executive office address in Massachusetts.

Who signed the Schedule 13G/A amendment for the filing parties?

Mohammed Fahad Al Khulaifi, Head of Compliance, signed the amendment on behalf of the filing parties. Two signature lines in the excerpt show the same name and title with a date of 05/12/2026.

SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

SCHEDULE 13G

UNDER THE SECURITIES EXCHANGE ACT OF 1934

(Amendment No. 1)

Sionna Therapeutics Inc

(Name of Issuer)

Common Stock SH

(Title of Class of Securities)

829401108

(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): 829401108

1

Names of Reporting Persons

Qatar Investment Authority

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

QATAR

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 2,020,258.00
6	Shared Voting Power 0.00
7	Sole Dispositive Power 2,020,258.00
8	Shared Dispositive Power 0.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

2,020,258.00

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)

4.5 %

12

Type of Reporting Person (See Instructions)

OO

SCHEDULE 13G

CUSIP Number(s): 829401108

1

Names of Reporting Persons

Q Healthcare Holding 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

QATAR

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 2,020,258.00
6	Shared Voting Power 0.00
7	Sole Dispositive Power 2,020,258.00
8	Shared Dispositive Power 0.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

2,020,258.00

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)

4.5 %

12

Type of Reporting Person (See Instructions)

IV

SCHEDULE 13G

Item 1.
(a)	Name of issuer: Sionna Therapeutics Inc
(b)	Address of issuer's principal executive offices: 21 HICKORY DRIVE, SUITE 500, WALTHAM, MA, 02451
Item 2.
(a)	Name of person filing: Qatar Investment Authority, Q Healthcare Holding LLC
(b)	Address or principal business office or, if none, residence: Qatar Investment Authority - Ooredoo Tower (Building 14), Al Dafna Street (Street 801), Al Dafna (Zone 61), Doha, Qatar / Q Healthcare Holding LLC - Ooredoo Tower (Building 14) Al Dafna Street (Street 801) Al Dafna (Zone 61), Doha, Qatar
(c)	Citizenship: Qatar Investment Authority - Qatar, Q Healthcare Holding LLC - Qatar
(d)	Title of class of securities: Common Stock SH
(e)	CUSIP No.: 829401108
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: 2,020,258
(b)	Percent of class: 4.5 %
(c)	Number of shares as to which the person has:
	(i) Sole power to vote or to direct the vote: 2,020,258
	(ii) Shared power to vote or to direct the vote: 0
	(iii) Sole power to dispose or to direct the disposition of: 2,020,258
	(iv) Shared power to dispose or to direct the disposition of: 0
Item 5.	Ownership of 5 Percent or Less of a Class.
	Ownership of 5 percent or less of a class
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. Q Healthcare Holding LLC is the wholly owned subsidiary of Qatar Investment Authority that acquired the security.
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.

Qatar Investment Authority

Signature:	Mohammed Fahad Al Khulaifi
Name/Title:	Head of Compliance
Date:	05/12/2026

Q Healthcare Holding LLC

Signature:	Mohammed Fahad Al-Khulaifi
Name/Title:	Head of Compliance
Date:	05/12/2026