BioLargo director Marshall acquires two stock options

The board-fee option was issued under BioLargo's 2024 Equity Incentive Plan.

Rhea-AI Filing Summary

BioLargo, Inc. director Dennis E. Marshall acquired two options on September 30, 2026. One covers 281,248 shares and replaced an option for 29,605 shares that expired unexercised; the other covers 234,375 shares and was issued as payment for $18,750 in board fees for the most recently completed quarterly period. Both options have an $0.08 exercise price and expire September 30, 2036.

Insider Trade Summary

Grant/Award: 515,623 shares

Grant/Award 2 txns

Insider Marshall Dennis E

Role Director

Type	Security	Shares	Price	Value
Grant/Award	Option to Purchase Common Stock F1, F2	281,248	--	--
Grant/Award	Option to Purchase Common Stock F3	234,375	--	--

Holdings After Transaction: Option to Purchase Common Stock — 6,290,692 contracts (Direct)

Footnotes (3)

1. F1. This Option was granted to Reporting Person to replace an option to purchase 29,605 shares that had been issued to compensate Reporting Person for services to the Issuer and had expired unexercised due to a discrepancy between the original exercise price and Issuer's current stock price, pursuant to plan adopted by the Issuer's Compensation Committee.
2. F2. Total reflects the expiration of options to purchase 29,605 shares that expired unexercised on September 30, 2026.
3. F3. This Option was issued to Reporting Person as payment for $18,750 in fees due to Reporting Person by Issuer in exchange for services on its board of directors for the most recently completed quarterly period, pursuant to the Issuer's 2024 Equity Incentive Plan. The number of shares in the Option is equal to the amount of fees due divided by the exercise price of the Option.

Key Figures

Option award shares: 281,248 shares Expired option shares: 29,605 shares Board-fee option shares: 234,375 shares +3 more

6 metrics

Option award shares 281,248 shares Granted September 30, 2026, to replace an option that expired unexercised

Expired option shares 29,605 shares Expired unexercised on September 30, 2026

Board-fee option shares 234,375 shares Issued for board services during the most recently completed quarterly period

Exercise price $0.08 per share Applies to both options

Board fees $18,750 Fees due for board services during the most recently completed quarterly period

Option expiration September 30, 2036 Expiration date for both options

Key Terms

exercise price, 2024 Equity Incentive Plan, expired unexercised

3 terms

exercise price financial

"divided by the exercise price of the Option"

The exercise price is the fixed amount at which you can buy or sell an asset, like a stock, when using an options contract. It matters because it helps determine whether exercising the option will be profitable or not, depending on the current market price. Think of it as the set price you agree on today to buy or sell later.

2024 Equity Incentive Plan financial

"pursuant to the Issuer's 2024 Equity Incentive Plan"

expired unexercised financial

"expired unexercised on September 30, 2026"

FAQ

AI-generated questions and answers. How Rhea-AI works. Not financial advice.

Why was Dennis E. Marshall granted 234,375 BLGO option shares?

The 234,375-share option was issued as payment for $18,750 in fees due to Dennis E. Marshall for board services during the most recently completed quarterly period. The option share count equals the fees due divided by the option's exercise price.

AI-generated analysis. How Rhea-AI works. Not financial advice.

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Available on EDGAR 10/02/2026 - 06:36 PM Accepted by SEC EDGAR 10/02/2026 - 06:36 PM Learn about SEC filing dates

SEC Form 4

FORM 4

UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934
or Section 30(h) of the Investment Company Act of 1940

OMB APPROVAL

OMB Number:			3235-0287
Estimated average burden
hours per response:			0.5

Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

Check this box to indicate that a transaction was made pursuant to a contract, instruction or written plan for the purchase or sale of equity securities of the issuer that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.

1. Name and Address of Reporting Person^*

Marshall Dennis E

(Last) (First) (Middle)

14921 CHESTNUT ST.

(Street)

WESTMINSTER CALIFORNIA 92683

(City) (State) (Zip)

UNITED STATES

(Country)

2. Issuer Name and Ticker or Trading Symbol
BIOLARGO, INC. [ BLGO ]

5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)

X	Director		10% Owner
	Officer (give title below)		Other (specify below)

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
09/30/2026

6. Individual or Joint/Group Filing (Check Applicable Line)

X	Form filed by One Reporting Person
	Form filed by More than One Reporting Person

4. If Amendment, Date of Original Filed (Month/Day/Year)

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	3. Transaction Code (Instr. 8)		4. Securities Acquired (A) or Disposed Of (D) (Instr. 3, 4 and 5)			5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4)	6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
			Code	V	Amount	(A) or (D)	Price

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Transaction Date (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	4. Transaction Code (Instr. 8)		5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5)		6. Date Exercisable and Expiration Date (Month/Day/Year)		7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4)		8. Price of Derivative Security (Instr. 5)	9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)	10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
				Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares
Option to Purchase Common Stock	$0.08	09/30/2026		A		281,248		09/30/2026	09/30/2036	Common Stock	281,248	(1)	6,056,317(2)	D
Option to Purchase Common Stock	$0.08	09/30/2026		A		234,375		09/30/2026	09/30/2036	Common Stock	234,375	(3)	6,290,692	D

Explanation of Responses:

1. This Option was granted to Reporting Person to replace an option to purchase 29,605 shares that had been issued to compensate Reporting Person for services to the Issuer and had expired unexercised due to a discrepancy between the original exercise price and Issuer's current stock price, pursuant to plan adopted by the Issuer's Compensation Committee.

2. Total reflects the expiration of options to purchase 29,605 shares that expired unexercised on September 30, 2026.

3. This Option was issued to Reporting Person as payment for $18,750 in fees due to Reporting Person by Issuer in exchange for services on its board of directors for the most recently completed quarterly period, pursuant to the Issuer's 2024 Equity Incentive Plan. The number of shares in the Option is equal to the amount of fees due divided by the exercise price of the Option.

	/s/ John R. Browning, attorney-in-fact	10/02/2026
	** 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 4 (b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.
* Form 4: SEC 1474 (03-26)