Rainier investor 683 Capital discloses 11.2% stake

Rainier Acquisition Corp (RNAQU) has a significant shareholder group led by 683 Capital Partners, LP, which, together with related entities, reports beneficial ownership of 862,500 Class A ordinary shares.

Rhea-AI Filing Summary

Rainier Acquisition Corp (RNAQU) has a significant shareholder group led by 683 Capital Partners, LP, which, together with related entities, reports beneficial ownership of 862,500 Class A ordinary shares. This represents 11.2% of Rainier’s Class A ordinary shares outstanding as of August 27, 2026.

The ownership is held by 683 Capital Partners, LP, with 683 Capital Management, LLC as its investment manager and Ari Zweiman as managing member of 683 Capital Management, LLC. All three reporting persons share voting and dispositive power over these 862,500 shares, with no sole voting or dispositive power reported. The percentage interest is based on 7,694,375 Class A ordinary shares outstanding as disclosed in Rainier’s prospectus for its units, which consist of Class A ordinary shares and redeemable warrants that initially trade together.

Key Figures

Shares beneficially owned: 862,500 Class A ordinary shares Ownership percentage: 11.2% Shares outstanding: 7,694,375 Class A ordinary shares +4 more

7 metrics

Shares beneficially owned 862,500 Class A ordinary shares Beneficially owned by 683 Capital Partners, LP as of August 27, 2026

Ownership percentage 11.2% Percentage of Class A ordinary shares beneficially owned by the reporting persons

Shares outstanding 7,694,375 Class A ordinary shares Outstanding as of August 27, 2026, assuming no exercise of the underwriters’ over-allotment option

Sole voting power 0 shares Sole voting power reported by each reporting person

Shared voting power 862,500 shares Shared voting power reported by each reporting person

CUSIP for units G73591110 CUSIP for Rainier Acquisition Corp’s units (shares and redeemable warrants)

Signature date September 3, 2026 Date Ari Zweiman signed in the stated capacities

Key Terms

beneficially owned, Redeemable Warrants, underwriters' over-allotment option, beneficially owned the 862,500 Class A Ordinary Shares, +1 more

5 terms

beneficially owned financial

"As of August 27, 2026, 683 Capital Partners, LP beneficially owned 862,500"

Beneficially owned describes securities or assets where a person has the economic rights and control—such as the right to receive dividends and to direct voting—even if legal title is held in another name. Think of it like having the keys and using a car that’s registered to someone else: you get the benefits and make decisions. Investors care because beneficial ownership reveals who truly controls value and voting power, affecting corporate decisions and takeover dynamics.

Redeemable Warrants financial

"Units (Class A Ordinary Shares, $0.0001 par vaue, and Redeemable Warrants)"

A redeemable warrant is a tradable right that lets its holder buy a company’s shares at a fixed price before a set date, but the issuer has the contract power to cancel (redeem) the warrant early under agreed terms. For investors this matters because early redemption can force decision-making, change the timing of when new shares might be created, and affect potential gains or dilution—much like a store coupon that the issuer can cancel by paying you off instead of letting you use it.

underwriters' over-allotment option financial

"outstanding as of August 27, 2026 which assumes no exercise of the underwriters' over-allotment option"

beneficially owned the 862,500 Class A Ordinary Shares financial

"may be deemed to have beneficially owned the 862,500 Class A Ordinary Shares"

Rule 13d-1(k)(2) regulatory

"filed on behalf of each of the undersigned pursuant to and in accordance with the provisions of Rule 13d-1(k)(2)"

FAQ

How many Rainier Acquisition Corp (RNAQU) shares does 683 Capital beneficially own?

683 Capital Partners, LP and related entities beneficially own 862,500 Class A ordinary shares of Rainier Acquisition Corp as of August 27, 2026, with shared voting and dispositive power over all of these shares.

What percentage of Rainier Acquisition Corp (RNAQU) does 683 Capital own?

The reporting group led by 683 Capital reports beneficial ownership of 11.2% of Rainier Acquisition Corp’s Class A ordinary shares, based on 7,694,375 shares outstanding as of August 27, 2026.

Who are the reporting persons in this Rainier Acquisition Corp (RNAQU) ownership filing?

The reporting persons are 683 Capital Partners, LP, 683 Capital Management, LLC, and Ari Zweiman. 683 Capital Management is investment manager to 683 Capital Partners, and Ari Zweiman is the managing member of 683 Capital Management.

What voting power does 683 Capital have over Rainier Acquisition Corp (RNAQU) shares?

The reporting persons have 0 shares with sole voting power and 862,500 shares with shared voting power, indicating all reported voting authority over Rainier Acquisition Corp shares is shared among the reporting persons.

How many Rainier Acquisition Corp (RNAQU) shares were outstanding when 683 Capital’s stake was calculated?

The 11.2% ownership figure is calculated based on 7,694,375 Class A ordinary shares outstanding as of August 27, 2026, which assumes no exercise of the underwriters’ over-allotment option.

What securities of Rainier Acquisition Corp (RNAQU) are referenced in this ownership report?

The report concerns units consisting of Class A ordinary shares with a par value of $0.0001 and redeemable warrants. Initially, each Class A ordinary share and warrant trades together as a unit under CUSIP G73591110.

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Available on EDGAR 09/03/2026 - 05:57 PM Accepted by SEC EDGAR 09/03/2026 - 05:53 PM Learn about SEC filing dates

SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

SCHEDULE 13G

UNDER THE SECURITIES EXCHANGE ACT OF 1934

Rainier Acquisition Corporation

(Name of Issuer)

Units (Class A Ordinary Shares, $0.0001 par vaue, and Redeemable Warrants)

(Title of Class of Securities)

G73591110

(CUSIP Number)

08/27/2026

(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): G73591110

1

Names of Reporting Persons

683 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

DELAWARE

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 0.00
6	Shared Voting Power 862,500.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 862,500.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

862,500.00

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)

11.2 %

12

Type of Reporting Person (See Instructions)

IA

SCHEDULE 13G

CUSIP Number(s): G73591110

1

Names of Reporting Persons

683 Capital Partners, LP

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

DELAWARE

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 0.00
6	Shared Voting Power 862,500.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 862,500.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

862,500.00

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)

11.2 %

12

Type of Reporting Person (See Instructions)

PN

SCHEDULE 13G

CUSIP Number(s): G73591110

1

Names of Reporting Persons

Ari Zweiman

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

UNITED STATES

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 0.00
6	Shared Voting Power 862,500.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 862,500.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

862,500.00

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)

11.2 %

12

Type of Reporting Person (See Instructions)

IN

SCHEDULE 13G

Item 1.
(a)	Name of issuer: Rainier Acquisition Corporation
(b)	Address of issuer's principal executive offices: 1 PENN PLAZA, 48TH FLOOR, NEW YORK, NEW YORK 10119
Item 2.
(a)	Name of person filing: 683 Capital Management, LLC 683 Capital Partners, LP Ari Zweiman Each of the foregoing is referred to as a "Reporting Person" and collectively as the "Reporting Persons."
(b)	Address or principal business office or, if none, residence: The principal business address for each of the Reporting Persons is 1700 Broadway, Suite 4200, New York, New York 10019.
(c)	Citizenship: 683 Capital Management, LLC - DELAWARE 683 Capital Partners, LP - DELAWARE Ari Zweiman - UNITED STATES
(d)	Title of class of securities: Units (Class A Ordinary Shares, $0.0001 par vaue, and Redeemable Warrants)
(e)	CUSIP Number(s): G73591110
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: ** As of the date of this Schedule 13G, a CUSIP number for the issuer's Class A Ordinary Shares is not available. Initially, each of the Class A Ordinary Shares and warrants to purchase Class A Ordinary Shares will trade as a unit. The CUSIP number set forth herein is the CUSIP number for the issuer's units. As of August 27, 2026, 683 Capital Partners, LP beneficially owned 862,500 Class A Ordinary Shares. 683 Capital Management, LLC, as the investment manager of 683 Capital Partners, LP, may be deemed to have beneficially owned the 862,500 Class A Ordinary Shares beneficially owned by 683 Capital Partners, LP. Ari Zweiman, as the Managing Member of 683 Capital Management, LLC, may be deemed to have beneficially owned the 862,500 Class A Ordinary Shares beneficially owned by 683 Capital Management, LLC. The following percentage is based on 7,694,375 Class A Ordinary Shares outstanding as of August 27, 2026 which assumes no exercise of the underwriters' over-allotment option, as disclosed in the Issuer's Prospectus on Form 424(b)(4) (Registration Statement No. 333-298076) filed with the Securities and Exchange Commission on August 27, 2026.
(b)	Percent of class: 11.2 %
(c)	Number of shares as to which the person has:
	(i) Sole power to vote or to direct the vote: See Cover Pages Items 5-9.
	(ii) Shared power to vote or to direct the vote: See Cover Pages Items 5-9.
	(iii) Sole power to dispose or to direct the disposition of: See Cover Pages Items 5-9.
	(iv) Shared power to dispose or to direct the disposition of: See Cover Pages Items 5-9.
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.
	If a group has filed this schedule pursuant to §240.13d-1(b)(1)(ii)(K), so indicate under Item 3(k) and attach an exhibit stating the identity and Item 3 classification of each member of the group. If a group has filed this schedule pursuant to §240.13d-1(c) or §240.13d-1(d), attach an exhibit stating the identity of each member of the group. See Exhibit A.
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.

683 Capital Management, LLC

Signature:	Ari Zweiman
Name/Title:	Managing Member
Date:	09/03/2026

683 Capital Partners, LP

Signature:	Ari Zweiman
Name/Title:	Authorized Person
Date:	09/03/2026

Ari Zweiman

Signature:	Ari Zweiman
Name/Title:	Self
Date:	09/03/2026

Exhibit Information

JOINT FILING AGREEMENT The undersigned hereby agree that the statement on Schedule 13G with respect to the Class A ordinary shares of Rainier Acquisition Corp dated as of September 3, 2026 is, and any further amendments thereto signed by each of the undersigned shall be, filed on behalf of each of the undersigned pursuant to and in accordance with the provisions of Rule 13d-1(k)(2) under the Securities Exchange Act of 1934, as amended. Dated: September 3, 2026 683 CAPITAL MANAGEMENT, LLC By: /s/ Ari Zweiman Ari Zweiman, Managing Member 683 CAPITAL PARTNERS, LP By: /s/ Ari Zweiman Ari Zweiman, Authorized Person /s/ Ari Zweiman Ari Zweiman