Mark A. Emalfarb - 23 Dec 2025 Form 4 Insider Report for DYADIC INTERNATIONAL INC (DYAI)

Role: CEO, Director, 10%+ Owner
Signature: /s/ Ping Rawson, attorney-in-fact
Issuer symbol: DYAI
Transactions as of: 23 Dec 2025
Net transactions value: $0
Form type: 4
Filing time: 29 Dec 2025, 17:00:32 UTC
Previous filing: 17 Sep 2025
Next filing: 06 Jan 2026
SEC: View on sec.gov

Reporting Owners (1)

Name	Relationship	Address	Signature	Signature date	CIK
EMALFARB MARK A	CEO, Director, 10%+ Owner	C/O DYADIC INTERNATIONAL, INC., 1044 NORTH U.S. HIGHWAY ONE, SUITE 201, JUPITER	/s/ Ping Rawson, attorney-in-fact	29 Dec 2025	0001328287

Derivative Securities (e.g., puts, calls, warrants, options, convertible securities)

Type	Sym	Class	Transaction	Value $	Shares	Change %	* Price $	Shares After	Date	Underlying Class	Amount	Exercise Price	Ownership	Footnotes
transaction	DYAI	Senior Secured Convertible Promissory Note due March 8, 2027	Disposed to Issuer	$1,000,000				0	23 Dec 2025	Common Stock	714,286	$1.40	Through Mark A Emalfarb Trust U/A/ DTD 10/1/1987	F1
transaction	DYAI	Senior Secured Convertible Promissory Note due Dec 31, 2027	Award	$1,000,000				$1,000,000	23 Dec 2025	Common Stock	952,381	$1.05	Through Mark A Emalfarb Trust U/A/ DTD 10/1/1987	F1

* An asterisk sign (*) next to the price indicates that the price is likely invalid.

Explanation of Responses:

Id	Content
F1	On December 23, 2025, Dyadic International, Inc. (the "Company") entered into an amendment (the "Amendment") to the Form of Senior Secured Convertible Promissory Note due March 8, 2027 (the "Convertible Notes"). Following the Amendment, the Convertible Notes will mature December 31, 2027 and their conversion price is $1.05. The Amendment was approved by the Company's board of directors, and did not involve the exchange of consideration between the Company and the holders.

Content

On December 23, 2025, Dyadic International, Inc. (the "Company") entered into an amendment (the "Amendment") to the Form of Senior Secured Convertible Promissory Note due March 8, 2027 (the "Convertible Notes"). Following the Amendment, the Convertible Notes will mature December 31, 2027 and their conversion price is $1.05. The Amendment was approved by the Company's board of directors, and did not involve the exchange of consideration between the Company and the holders.