8-K

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

August 29, 2025

Date of Report: (Date of earliest event reported)

Cyanotech Corporation

(Exact name of registrant as specified in its charter)

Nevada<br><br> <br>(State or other jurisdiction of<br><br> <br>incorporation)	000-14602<br><br> <br>(Commission File Number)	91-1206026<br><br> <br>(IRS Employer Identification<br><br> <br>Number)

73-4460 Queen Kaahumanu Highway, Suite #102, Kailua Kona, HI 96740

(Address of principal executive offices)

(808) 326-1353

(Registrant’s telephone number)

Not Applicable

(Former name or former address, if changed since last report)

Securities registered pursuant to Section 12(b) of the Act: none

Check the appropriate box below if the Form 8-K filing 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)
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☐	Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))
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☐	Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))
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Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 or Rule 12b-2 of the Securities Exchange Act of 1934.

Emerging growth company ☐

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. ☐

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Item 1.01.	Entry into a Material Definitive Agreement.

On August 29, 2025, Cyanotech Corporation (the “Company”) entered into a Fifth Amendment (the “Amendment”) to the Amended and Restated Promissory Note with Skywords Family Foundation, Inc. (“Skywords”), dated as of April 12, 2021 and amended on December 14, 2022, August 13, 2023, August 9, 2024 and May 2, 2025 (the “Note”). The Amendment increases the amount that the Company may borrow from time to time under the Note from $4,000,000 to $4,600,000 on a revolving basis (the “Revolver”), lowers the minimum draw amount from $250,000 to $200,000, and amends the maturity date of the Revolver from April 12, 2026 to April 12, 2027. All other terms of the Note remain the same. Skywords is controlled by Michael Davis, the Company’s Chairman of the Board of Directors and largest stockholder.

The foregoing description of the Amendment does not purport to be complete and is qualified in its entirety by reference to the full text of the Amendment, a copy of which is filed as Exhibit 10.1 to this Current Report on Form 8-K and is incorporated herein by reference.

Item 2.03.	Creation of a Direct Financial Obligation or an Obligation under an Off-Balance Sheet Arrangement of a Registrant.

The disclosure in Item 1.01 of this Current Report on Form 8-K is incorporated herein by reference.

Item 9.01	Financial Statements and Exhibits.

(d) Exhibits

Exhibit<br><br> <br>Number	Name and/or Identification of Exhibit
10.1	Fifth Amendment to Amended and Restated Promissory Note, dated August 29, 2025, by and between Skywords Family Foundation, Inc. and Cyanotech Corporation
104	Cover Page Interactive Data File (embedded within the Inline XBRL document)

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SIGNATURES

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.

	CYANOTECH CORPORATION
Dated: September 2, 2025	/s/ Matthew K. Custer
	By:	Matthew K. Custer
		President and Chief Executive Officer

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EXHIBIT INDEX

Exhibit<br><br> <br>Number	Name and/or Identification of Exhibit
10.1	Fifth Amendment to Amended and Restated Promissory Note, dated August 29, 2025, by and between Skywords Family Foundation, Inc. and Cyanotech Corporation
104	Cover Page Interactive Data File (embedded within the Inline XBRL document)

ex_858370.htm

Exhibit 10.1

FIFTH AMENDMENT TO

AMENDED AND RESTATED PROMISSORY NOTE

This FIFTH AMENDMENT (this “Amendment”) to the Amended and Restated Promissory Note (the “Note”), by and between Skywords Family Foundation Inc. (“Lender”) and Cyanotech Corporation, a Nevada Corporation (“Borrower”), dated as of April 12, 2021, as amended on December 14, 2022, August 14, 2023, August 9, 2024 and May 2, 2025 is entered into as of August 29, 2025. Except as otherwise provided herein, all capitalized terms not specifically defined herein will have the same meanings ascribed to them in the Note.

RECITALS

WHEREAS, Lender and Borrower are parties to the Note, pursuant to which Borrower is entitled to request certain Revolving Loans from Lender up to the Maximum Revolving Amount, subject to the terms and conditions of the Note; and

WHEREAS, Lender and Borrower desire to amend the Note to, among other things, increase the Maximum Revolving Amount from $4,000,000 to $4,600,000 and extend the maturity date applicable to borrowings under the Note.

NOW, THEREFORE, in consideration of the mutual covenants contained herein and other good and valuable consideration, the receipt and sufficiency of which are hereby acknowledged, Borrower and Lender agree as follows:

AGREEMENT

1.	Amendments to the Note. The Note is hereby amended as follows:
a.	The term “Maximum Revolving Amount” as used in the Note is hereby defined to be Four Million Six Hundred Thousand Dollars ($4,600,000), and all uses of the term “Maximum Revolving Amount” in the Note shall be deemed to be references to Four Million Six Hundred Thousand Dollars ($4,600,000) rather than Four Million Dollars ($4,000,000).
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b.	The third sentence of Section 2 shall be amended and restated in its entirety as follows:<br><br> <br><br><br> <br>Each written request shall specify the amount and date of the advance; provided that each advance shall be in an amount greater than or equal to Two Hundred Thousand Dollars ($200,000.00).
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c.	The second and third sentences of Section 4 shall be amended and restated in their entirety as follows:<br><br> <br><br><br> <br>“The aggregate outstanding principal of each of the Loans and accrued but unpaid interest shall be due and payable on April 12, 2027 (the “Maturity Date”).”
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2.             Effect of Amendment. Except as otherwise explicitly provided in this Amendment, the Note will remain unchanged and in full force and effect. The term “Note” as used in the Agreement shall for all purposes refer to the Note as amended on December 14, 2022, August 14, 2023, August 9, 2024 and May 2, 2025 and as further amended by this Amendment.

3.          Complete Agreement. The Note, as amended on December 14, 2022, August 14, 2023, August 9, 2024 and May 2, 2025 and as further amended by this Amendment, represents the complete agreement and understanding among the parties with respect to, and supersede and preempt any prior understandings, agreements or representations by or among the parties, written or oral, which may have related to, the subject matter hereof in any way.

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4. Counterparts. This Amendment may be executed in separate counterparts (including by means of facsimile or by electronic transmission in portable document format (pdf) or comparable electronic transmission), each of which is deemed to be an original and all of which taken together constitute one and the same document.

5.            Governing Law. All issues and questions concerning the construction, validity, enforcement and interpretation of this Amendment and the exhibits and schedules hereto shall be governed by, and construed in accordance with, the laws of the State of California and as set forth in Section 17 of the Note, as if an original part thereof.

IN WITNESS WHEREOF, Borrower and Lender have executed this Amendment effective as of the date first above written.

BORROWER:
Cyanotech Corporation
By:/s/Matthew Custer<br><br> <br>Name: Matthew Custer<br><br> <br>Title: President and CEO
LENDER:
Skywords Family Foundation, Inc.
By:/s/Michael A. Davis<br><br> <br>Name: Michael A. Davis<br><br> <br>Title: President