RP-affiliated funds report 6.3% stake in 1RT Acquisition

1RT Acquisition Corp. Schedule 13G/A jointly filed reporting beneficial ownership by RP Investment Advisors LP and four affiliated funds.

Rhea-AI Filing Summary

1RT Acquisition Corp. Schedule 13G/A jointly filed reporting beneficial ownership by RP Investment Advisors LP and four affiliated funds. The filing lists combined shared dispositive ownership positions for the funds, including 1,080,906 shares (6.3%) held by RP Investment Advisors as representative, based on March 18, 2026 outstanding share count.

The cover pages show individual fund holdings: RP Select Opportunities Master Fund Ltd. 320,783 shares (1.9%), RP Debt Opportunities Fund Ltd. 194,886 shares (1.1%), RP Alternative Global Bond Fund 480,228 shares (2.8%), and RP Alternative Credit Opportunities Fund 85,009 shares (0.5%). The filing is signed by Richard Pilosof on behalf of RP Investment Advisors.

Insights

Institutional Ownership Analyst

Large passive holdings disclosed by RP-affiliated funds; positions are context for ownership concentration.

The cover pages list exact shared dispositive holdings, including 1,080,906 shares (6.3%) tied to RP Investment Advisors based on an outstanding base of March 18, 2026. These figures reflect reported beneficial positions, not operational actions.

Cash‑flow treatment and trading intent are not stated; subsequent filings would disclose changes in holdings. Filings note disclaimers regarding Section 13(d)/13(g) beneficial‑owner status.

Corporate Governance Specialist

Joint filing clarifies voting/dispositive power across related funds and advisor.

The statement is jointly filed by RP Investment Advisors LP and four funds and documents shared voting and dispositive power figures for each fund. Each reporting person includes a declaration limiting admissions under Section 13(d)/13(g).

Investors tracking ownership should note the March 18, 2026 outstanding share base cited; follow‑up Schedule 13D/G amendments may update these positions.

Key Figures

Shares outstanding used: 17,250,000 shares RP Investment Advisors position: 1,080,906 shares RP Select Opportunities Master Fund Ltd.: 320,783 shares +3 more

6 metrics

Shares outstanding used 17,250,000 shares used as the base for percentage calculations as of <date>March 18, 2026</date>

RP Investment Advisors position 1,080,906 shares shared dispositive power; <date>March 18, 2026</date>

RP Select Opportunities Master Fund Ltd. 320,783 shares shared dispositive power; <date>March 18, 2026</date>

RP Debt Opportunities Fund Ltd. 194,886 shares shared dispositive power; <date>March 18, 2026</date>

RP Alternative Global Bond Fund 480,228 shares shared dispositive power; <date>March 18, 2026</date>

RP Alternative Credit Opportunities Fund 85,009 shares shared dispositive power; <date>March 18, 2026</date>

Key Terms

shared dispositive power, beneficially owned, Section 13(d) or 13(g)

3 terms

shared dispositive power regulatory

"Shared Dispositive Power 1,080,906.00"

beneficially owned regulatory

"Amount beneficially owned: See Item 9 on the cover page(s) hereto."

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.

Section 13(d) or 13(g) regulatory

"shall not be construed as an admission that such person is, for the purposes of Section 13(d) or 13(g)"

FAQ

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

What ownership stake does RP Investment Advisors report in ONCH?

RP Investment Advisors reports shared dispositive ownership of 1,080,906 shares (6.3%) based on 17,250,000 shares outstanding as of March 18, 2026. The figure appears on the cover page of the Schedule 13G/A.

Which affiliated funds are included in the joint Schedule 13G/A for ONCH?

The joint filing covers RP Select Opportunities Master Fund Ltd., RP Debt Opportunities Fund Ltd., RP Alternative Global Bond Fund, and RP Alternative Credit Opportunities Fund, with individual holdings listed on the cover pages.

How many shares does RP Alternative Global Bond Fund report owning in ONCH?

The filing shows 480,228 shares (2.8%) held by RP Alternative Global Bond Fund, calculated using the 17,250,000 shares outstanding figure as of March 18, 2026

Does the filing state whether RP Investment Advisors is the beneficial owner for Section 13(d)/13(g) purposes?

The filing includes a declaration that the reporting persons do not admit they are beneficial owners for purposes of Section 13(d) or 13(g), and notes possible group treatment; it is a legal disclaimer included in Item 2.

What voting and dispositive powers are reported for the funds in ONCH?

Cover pages list 0 sole voting/dispositive power and specified shared voting and shared dispositive powers for each fund (for example, 1,080,906 shared for RP Investment Advisors). Exact numbers are on the cover pages.

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

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Accepted by SEC EDGAR 05/15/2026 - 04:33 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)

1RT Acquisition Corp.

(Name of Issuer)

Class A ordinary shares, par value $0.0001 per share

(Title of Class of Securities)

G6757R105

(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): G6757R105

1

Names of Reporting Persons

RP Investment Advisors 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

ONTARIO, CANADA

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 0.00
6	Shared Voting Power 1,080,906.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 1,080,906.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

1,080,906.00

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)

6.3 %

12

Type of Reporting Person (See Instructions)

IA, FI, PN

Comment for Type of Reporting Person: This calculation is rounded to the nearest tenth and is based upon 17,250,000 Class A ordinary shares issued and outstanding as of March 18, 2026, as reported by the Issuer in its Annual Report on Form 10-K filed with the Securities and Exchange Commission on March 27, 2026.

SCHEDULE 13G

CUSIP Number(s): G6757R105

1

Names of Reporting Persons

RP Select Opportunities Master Fund Ltd.

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 0.00
6	Shared Voting Power 320,783.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 320,783.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

320,783.00

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)

1.9 %

12

Type of Reporting Person (See Instructions)

FI

Comment for Type of Reporting Person: This calculation is rounded to the nearest tenth and is based upon 17,250,000 Class A ordinary shares issued and outstanding as of March 18, 2026, as reported by the Issuer in its Annual Report on Form 10-K filed with the Securities and Exchange Commission on March 27, 2026.

SCHEDULE 13G

CUSIP Number(s): G6757R105

1

Names of Reporting Persons

RP Debt Opportunities Fund Ltd.

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 0.00
6	Shared Voting Power 194,886.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 194,886.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

194,886.00

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)

1.1 %

12

Type of Reporting Person (See Instructions)

FI

Comment for Type of Reporting Person: This calculation is rounded to the nearest tenth and is based upon 17,250,000 Class A ordinary shares issued and outstanding as of March 18, 2026, as reported by the Issuer in its Annual Report on Form 10-K filed with the Securities and Exchange Commission on March 27, 2026.

SCHEDULE 13G

CUSIP Number(s): G6757R105

1

Names of Reporting Persons

RP Alternative Global Bond 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

ONTARIO, CANADA

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 0.00
6	Shared Voting Power 480,228.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 480,228.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

480,228.00

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)

2.8 %

12

Type of Reporting Person (See Instructions)

FI

Comment for Type of Reporting Person: This calculation is rounded to the nearest tenth and is based upon 17,250,000 Class A ordinary shares issued and outstanding as of March 18, 2026, as reported by the Issuer in its Annual Report on Form 10-K filed with the Securities and Exchange Commission on March 27, 2026.

SCHEDULE 13G

CUSIP Number(s): G6757R105

1

Names of Reporting Persons

RP Alternative Credit Opportunities 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

ONTARIO, CANADA

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 0.00
6	Shared Voting Power 85,009.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 85,009.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

85,009.00

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)

0.5 %

12

Type of Reporting Person (See Instructions)

FI

Comment for Type of Reporting Person: This calculation is rounded to the nearest tenth and is based upon 17,250,000 Class A ordinary shares issued and outstanding as of March 18, 2026, as reported by the Issuer in its Annual Report on Form 10-K filed with the Securities and Exchange Commission on March 27, 2026.

SCHEDULE 13G

Item 1.
(a)	Name of issuer: 1RT Acquisition Corp.
(b)	Address of issuer's principal executive offices: PO BOX 309, UGLAND HOUSE, PO BOX 309, UGLAND HOUSE, GRAND CAYMAN, MONTANA, KY1-1104
Item 2.
(a)	Name of person filing: This statement is jointly filed by and on behalf of each of RP Investment Advisors LP, RP Select Opportunities Master Fund Ltd., RP Debt Opportunities Fund Ltd., RP Alternative Global Bond Fund and RP Alternative Credit Opportunities Fund. RP Select Opportunities Master Fund Ltd., RP Debt Opportunities Fund Ltd., RP Alternative Global Bond Fund and RP Alternative Credit Opportunities Fund (the "Funds") are the record and direct beneficial owners of the securities covered by this statement. RP Investment Advisors LP is the investment advisor of, and may be deemed to be beneficially own securities owned by, the Funds. Each reporting person declares that neither the filing of this statement nor anything herein shall be construed as an admission that such person is, for the purposes of Section 13(d) or 13(g) of the Act or any other purpose, the beneficial owner of any securities covered by this statement. Each of the reporting persons may be deemed to be a member of a group with respect to the Issuer or securities of the Issuer for the purposes of Section 13(d) or 13(g) of the Act. Each reporting person declares that neither the filing of this statement nor anything herein shall be construed as an admission that such person is, for the purposes of Section 13(d) or 13(g) of the Act or any other purpose, (i) acting (or has agreed or is agreeing to act together with any person) as a partnership, limited partnership, syndicate, or other group for the purpose of acquiring, holding, or disposing of securities of the Issuer or otherwise with respect to the Issuer or any securities of the Issuer or (ii) a member of any group with respect to the Issuer or any securities of the Issuer.
(b)	Address or principal business office or, if none, residence: The address of the principal business office of each of the reporting persons is 39 Hazelton Avenue, Toronto, Ontario, Canada, M5R 2E3.
(c)	Citizenship: See Item 4 on the cover page(s) hereto.
(d)	Title of class of securities: Class A ordinary shares, par value $0.0001 per share
(e)	CUSIP No.: G6757R105
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(s) hereto.
(b)	Percent of class: See Item 11 on the cover page(s) hereto.
(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(s) hereto.
	(ii) Shared power to vote or to direct the vote: See Item 6 on the cover page(s) hereto.
	(iii) Sole power to dispose or to direct the disposition of: See Item 7 on the cover page(s) hereto.
	(iv) Shared power to dispose or to direct the disposition of: See Item 8 on the cover page(s) hereto.
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.

RP Investment Advisors LP

Signature:	/s/ Richard Pilosof
Name/Title:	Richard Pilosof, Chief Executive Officer, RP Investment Advisors LP by its General Partner RP Investment Advisors GP Inc.
Date:	05/15/2026

RP Select Opportunities Master Fund Ltd.

Signature:	/s/ Richard Pilosof
Name/Title:	Richard Pilosof, Chief Executive Officer, RP Investment Advisors LP by its General Partner RP Investment Advisors GP Inc.
Date:	05/15/2026

RP Debt Opportunities Fund Ltd.

Signature:	/s/ Richard Pilosof
Name/Title:	Richard Pilosof, Chief Executive Officer, RP Investment Advisors LP by its General Partner RP Investment Advisors GP Inc.
Date:	05/15/2026

RP Alternative Global Bond Fund

Signature:	/s/ Richard Pilosof
Name/Title:	Richard Pilosof, Chief Executive Officer, RP Investment Advisors LP by its General Partner RP Investment Advisors GP Inc.
Date:	05/15/2026

RP Alternative Credit Opportunities Fund

Signature:	/s/ Richard Pilosof
Name/Title:	Richard Pilosof, Chief Executive Officer, RP Investment Advisors LP by its General Partner RP Investment Advisors GP Inc.
Date:	05/15/2026

Exhibit Information

Exhibit 99.1 Joint Filing Agreement (filed herewith).