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SEC Form 3

FORM 3

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 INITIAL STATEMENT OF BENEFICIAL OWNERSHIP OF SECURITIES Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934 or Section 30(h) of the Investment Company Act of 1940

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1. Name and Address of Reporting Person* AEROEQUITY GP, LLC (Last) (First) (Middle) C/O AE INDUSTRIAL PARTNERS, LP 6700 BROKEN SOUND PKWY NW (Street) BOCA RATON FL 33487 (City) (State) (Zip)	2. Date of Event Requiring Statement (Month/Day/Year) 01/29/2026	3. Issuer Name and Ticker or Trading Symbol Yellowstone Midco Holdings II, LLC [ YSS ]
		4. Relationship of Reporting Person(s) to Issuer (Check all applicable) Director X 10% Owner Officer (give title below) Other (specify below)	5. If Amendment, Date of Original Filed (Month/Day/Year)
			6. Individual or Joint/Group Filing (Check Applicable Line) Form filed by One Reporting Person X Form filed by More than One Reporting Person

Table I - Non-Derivative Securities Beneficially Owned
1. Title of Security (Instr. 4)	2. Amount of Securities Beneficially Owned (Instr. 4)	3. Ownership Form: Direct (D) or Indirect (I) (Instr. 5)	4. Nature of Indirect Beneficial Ownership (Instr. 5)
Common Stock	30,196,088(1)(2)	I	See Footnotes(1)(2)

Table II - Derivative Securities Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 4)	2. Date Exercisable and Expiration Date (Month/Day/Year)		3. Title and Amount of Securities Underlying Derivative Security (Instr. 4)		4. Conversion or Exercise Price of Derivative Security	5. Ownership Form: Direct (D) or Indirect (I) (Instr. 5)	6. Nature of Indirect Beneficial Ownership (Instr. 5)
	Date Exercisable	Expiration Date	Title	Amount or Number of Shares

1. Name and Address of Reporting Person* AEROEQUITY GP, LLC (Last) (First) (Middle) C/O AE INDUSTRIAL PARTNERS, LP 6700 BROKEN SOUND PKWY NW (Street) BOCA RATON FL 33487 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer Director X 10% Owner Officer (give title below) Other (specify below)

1. Name and Address of Reporting Person* GREENE MICHAEL ROBERT (Last) (First) (Middle) C/O AE INDUSTRIAL PARTNERS, LP 6700 BROKEN SOUND PKWY NW (Street) BOCA RATON FL 33487 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer Director X 10% Owner Officer (give title below) Other (specify below)

1. Name and Address of Reporting Person* ROWE DAVID H. (Last) (First) (Middle) C/O AE INDUSTRIAL PARTNERS, LP 6700 BROKEN SOUND PKWY NW (Street) BOCA RATON FL 33487 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer Director X 10% Owner Officer (give title below) Other (specify below)

Explanation of Responses:

1. Consists of 2,832,488 shares held by AE Industrial Partners Fund II, LP, 1,813,066 shares held by AE Industrial Partners Fund II-A, LP, 6,842 shares held by AE Industrial Partners Fund II-B, LP, 10,908,489 shares held by AE Industrial Partners Fund III, LP, 3,258,380 shares held by AE Industrial Partners Fund III-A, LP, 566,675 shares held by AE Aerospace Opportunities Fund, 8,757,636 shares held by AE Co-Investment Partners Fund III-Y, LP (CIV), 1,475,343 shares held by AE Co-Investment Partners Fund III Y-2, LP, 23,916 shares held by AE Industrial PSO Equity Partners, LP and 553,253 shares held by AE Industrial Partners PBCI Aggregator, LP.

2. Each entity described in footnote (1) is ultimately controlled by AeroEquity GP, LLC. AeroEquity GP, LLC is controlled by its managing members, Michael Greene and David Rowe. Messrs. Greene and Rowe make all voting and investment decisions with respect to the securities held by AE Industrial Partners. Each of the entities and individuals named above disclaims beneficial ownership of the securities held by AE Industrial Partners, except to the extent of its pecuniary interest therein.

Remarks:

Exhibit 24.1 - Power of Attorney

	AeroEquity GP, LLC /s/ Michael Greene, Authorized Signatory	01/29/2026
	/s/ Michael Greene	01/29/2026
	/s/ David H. Rowe	01/29/2026
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* If the form is filed by more than one reporting person, see Instruction 5 (b)(v).
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