Form 8-K

8-K — Yorkville Acquisition Corp.

Accession: 0001104659-26-048537

Filed: 2026-04-24

Period: 2026-04-22

CIK: 0002064658

SIC: 6199 (FINANCE SERVICES)

Item: Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers: Compensatory Arrangements of Certain Officers

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UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 8-K

CURRENT

REPORT

Pursuant

to Section 13 or 15(d) of the Securities Exchange Act of 1934

Date of report (Date of earliest event reported):

April 22, 2026

Yorkville Acquisition Corp.

(Exact name of registrant as specified in its

charter)

Cayman Islands

001-42720

98-1850073

(State or other jurisdiction

of incorporation)

(Commission

File Number)

(I.R.S. Employer

Identification No.)

1012 Springfield Avenue

Mountainside, NJ

07092

(Address of principal executive offices)

(Zip Code)

(201) 985-8300

(Registrant’s telephone number, including

area code)

N/A

(Former name or former address, if changed

since last report)

Check the appropriate box below if the Form 8-K is intended to simultaneously satisfy the filing obligation of the registrant under

any of the following provisions:

¨ Written communications pursuant to Rule 425 under the Securities

Act (17 CFR 230.425)

¨ Soliciting

material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

¨ Pre-commencement

communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

¨ Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

Securities registered

pursuant to Section 12(b) of the Act:

Title of each

class

Trading

Symbol(s)

Name of each exchange on

which

registered

Units, each consisting of one Class A ordinary share and one-third of one redeemable warrant

MCGAU

The Nasdaq Stock Market LLC

Class A ordinary shares, par value $0.0001 per share

MCGA

The Nasdaq Stock Market LLC

Warrants, each whole warrant exercisable for one Class A ordinary share at an exercise price of $11.50

MCGAW

The Nasdaq Stock Market LLC

Indicate by check mark whether the registrant is an emerging growth

company as defined in Rule 405 of the Securities Act of 1933 (§230.405 of this chapter) or Rule 12b-2 of the Securities

Exchange Act of 1934 (§240.12b-2 of this chapter).

Emerging growth company x

an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying

with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act.¨

Item 5.02 Departure of Directors or Certain

Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers.

Departure of Director and Executive Officer

On April 22, 2026, Mr. Kevin McGurn

notified the board of directors of Yorkville Acquisition Corp. (the “Company”) of his resignation as Chief Executive Officer

and as a director of the Company, effective immediately. Mr. McGurn’s resignation was not the result of any dispute or disagreement

with the Company on any matter, whether related to the Company’s operations, policies, practices or otherwise. The Company expresses

its gratitude to Mr. McGurn for his dedicated service.

Appointment of New Executive Officer

On April 22, 2026, Mr. Troy Rillo was

appointed as Chief Executive Officer of the Company by the Company’s board of directors, effective immediately. Mr. Rillo will

continue to serve as Chief Financial Officer of the Company.

Mr. Rillo, 57, has served as Chief Financial

Officer of the Company since August 2025. Mr. Rillo is a partner with Yorkville Advisors where, since 2004, he has been instrumental

in the firm’s growth and strategic direction. Mr. Rillo is an accomplished business executive and attorney with extensive experience

in corporate finance, securities law, and investment management. Mr. Rillo also currently serves as Co-Chief Executive Officer of

Yorkville Securities LLC, an SEC registered broker-dealer and member of FINRA, and President and Chief Executive Officer, and member of

the Board of Managers, of Yorkville America, LLC, an affiliated SEC-registered investment adviser focused on branded investment products,

including separately managed accounts and exchange-traded funds. Additionally, Mr. Rillo has served as the Chief Financial Officer

at Texas Ventures Acquisition III Corp since September 2025, and as the Chief Financial Officer of Blue Water Acquisition Corp. III

since November 2025. Prior to joining Yorkville Advisors, Mr. Rillo was a corporate and securities partner at K&L Gates

LLP, a leading international law firm, where he advised public and private companies on capital-raising transactions, mergers and acquisitions,

and securities compliance. Mr. Rillo is widely recognized as an authority in corporate and securities law and is a frequent speaker

on related topics. He earned both his J.D. and B.S. in Finance, magna cum laude, from the University of Florida. While in law school,

he served as a member of the Florida Law Review and was elected to the Order of the Coif. He is admitted to practice law in New Jersey

and Florida.

No family relationships exist between Mr. Rillo and any of the

Company’s directors or other executive officers. There is no arrangement or understanding between Mr. Rillo and any other person

pursuant to which he was selected as Chief Executive Officer. There is no material plan, contract or arrangement (whether or not written)

to which Mr. Rillo is a party or in which he participates that was entered into, or materially amended, in connection with his appointment

as Chief Executive Officer, and no grant or award (or modification thereto) was made to Mr. Rillo under any such plan, contract or

arrangement in connection with his appointment. Mr. Rillo is a Partner of Yorkville Advisors, an affiliate of Yorkville Acquisition

Sponsor, LLC, the Company's sponsor (the “Sponsor”). As a result, Mr. Rillo may be deemed to have an indirect interest

in the arrangements between the Company and the Sponsor (and its affiliates) that have been previously described in the Company's filings

with the Securities and Exchange Commission. Other than as previously disclosed or described herein, there are no transactions involving

Mr. Rillo that would require disclosure under Item 404(a) of Regulation S-K.

SIGNATURE

Pursuant to the requirements

of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto

duly authorized.

YORKVILLE ACQUISITION CORP.

By:

/s/ Troy Rillo

Name: Troy Rillo

Title: Chief Executive Officer and Chief Financial Officer

Date: April 24, 2026

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Entity Registrant Name

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Entity Incorporation, State or Country Code

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Title of 12(b) Security

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Security Exchange Name

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