Company: HYAC-WT
Filing Date: 2025-07-15
Form Type: DEFA14A
Source: 0001104659-25-068092
Chunk: 2

Company: Haymaker Acquisition Corp. 4
Filing Date: 2025-07-15
Form: DEFA14A
Chunk 2
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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)) |

<div align='center'>Securities registered pursuant to Section 12(b)
of the Act:</div>

| 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-half of one redeemable warrant                   |     | HYACU     |     | The New York Stock Exchange |
| Class A ordinary shares,                                                            
 par value $0.0001 per share                                                         |     | HYAC      |     | The New York Stock Exchange |
| Warrants, each whole warrant                                                        
 exercisable for one Class A ordinary share at an exercise price of $11.50 per share |     | HYAC WS   |     | The New York Stock Exchange |

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

If 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 1.01 | Entry into a Material Definitive Agreement. |

On July 15, 2025, Haymaker Sponsor IV LLC (the “Sponsor”)
agreed to make monthly deposits (each deposit, a “Contribution” and collectively, the “Contributions”),
each in an amount equal to the lesser of (i) $0.025 for each outstanding Class A ordinary share, par value $0.0001 per share (the “Class A Ordinary Shares”), of Haymaker Acquisition Corp. 4 (