BIOLARGO, INC.

The Company recognizes an expected allowance for credit losses with respect to its note and accounts receivable. In addition, also at each reporting date, this estimate is updated to reflect any changes in credit risk since the receivable was initially recorded. This estimate is calculated on a pooled basis where similar risk characteristics exist. Accounts receivable are evaluated individually when they donot share similar risk characteristics which could exist in circumstances where amounts are considered at risk or uncollectible This estimate is adjusted for management's assessment of current conditions, reasonable and supportable forecasts regarding future events, and any other factors deemed relevant by the Company. The Company believes historical loss information is a reasonable starting point in which to calculate the expected allowance for credit losses. The Company writes off receivables when there is information that indicates the customer is facing significant financial difficulty and there isno possibility of recovery. If any recoveries are made from any accounts previously written off, they will be recognized in operations or an offset to note and credit loss expense in the year of recovery, in accordance with the entity's accounting policy election.

On* June 6, 2025,ONM Environmental entered into an amendment to the June 2021Preferred Master Manufacturing Agreement with Ikigai Holdings, LLC and Pooph Inc. to allow Pooph Inc. to pay past due amounts of $1,378,141 in royalties and $2,385,468 on product invoices through a weekly payment plan bearing 10% interest and maturing July 3, 2026 (the “PMMA Amendment”). This amount was recorded on our balance sheet at June 30, 2025,as a note receivable. The PMMA Amendment also modified payment and invoicing terms on existing and future product purchase orders, and allowed ONM Environmental to withhold product if the payment terms werenot* met. On* August 5, 2025,Pooph Inc. delivered a royalty report due for thesecond* quarter of2025, but didnot pay the $463,520 in royalties due. On* August 15, 2025,it failed to make the weekly payment required pursuant to the PMMA Amendment, and hasnot* made a payment since. On* September 19, 2025,Pooph Inc. disclosed that it had been working independently on developing a new formula for Pooph-branded products to replace BioLargo's formula, and that it was terminating the Preferred Master Manufacturing Agreement, citing the refusal to deliver products. On September 24, 2025,BioLargo and ONM delivered notice to Pooph that the grant of license was immediately revoked due to Pooph’s failure to pay royalties, and that it was terminating the License Agreement in its entirety with150* days’ notice. The notice further advised that Pooph isnot allowed to market or sell products that incorporate, use, or are based on, in whole or in part, BioLargo’s patents and proprietary information, including butnot limited to know-how, disclosed to Pooph, and that absent reinstatement of the grant of license, Pooph must immediately stop marketing and selling any such products in its possession, custody or control (or sold through market portals or platforms such as Amazon). On* November 11, 2025,BioLargo Inc. and ONM Environmental filed a lawsuit against Pooph Inc. and Ikigai Marketing Works LLC (successor entity to Ikigai Holdings LLC) in the United States District Court for the Central District of California. (See Note13*, "Legal Proceedings".)

During thethree months ended* September 30, 2025,BioLargo management determined that the note receivable and accounts receivable owed by Pooph Inc. were fully impaired, resulting in a $3,849,000 credit loss expense recorded on our condensed consolidated statement of operations, which reduced operating income and current assets by that amount. There wereno* write-offs of accounts receivable during thethree andnine months ended* September 30, 2025and2024.*

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Credit Concentration

We have a limited number of customers that account for significant portions of our revenue. During thethree andnine months ended* September 30, 2025and2024*, one customer accounted for more than10% of consolidated revenues:

At* September 30, 2025* and* December 31, 2024*, one customer accounted for more than10% of consolidated accounts receivable (see Note7):

Inventory

Inventories are stated at the lower of cost or net realizable value using the average cost method. There wasno allowance for obsolete inventory as of* September 30, 2025*, and* December 31, 2024* Inventories consisted of the following (in thousands):

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Other Non-Current Assets

Other non-current assets consisted of (i) security deposits related to our business offices, (ii)three patents acquired on* October 22, 2021,*for $34,000, and (iii) interest receivable.

Equity Method of Accounting

On* March 20, 2020,*we invested $100,000 into a South Korean entity (Odin Co. Ltd., “Odin”) pursuant to a Joint Venture agreement we had entered into with BKT Co. Ltd. and its U.S. based subsidiary, Tomorrow Water. We received a 40% non-dilutive equity interest, and BKT and Tomorrow Water each received 30% equity interests for an aggregate $150,000 investment.

We account for our investment in the joint venture under the equity method of accounting. We have determined that while we have significant influence over the joint venture through our technology license and our position on the Board of Directors, we donot control the joint venture or are otherwise involved in managing the entity and we own less than a majority of the equity. Therefore, we recognized the investment on our condensed consolidated balance sheets and record an increase or decrease of the recorded balance by our percentage ownership of the profits or losses in the joint venture. For thethree andnine months ended* September 30, 2025*, the increase of our investment interest totaled $9,000, compared to a reduction of our investment totaling $3,000 and $4,000 in the same periods in2024.

Impairment

Long-lived and definite lived intangible assets are reviewed for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset* may**not* be recoverable. If the sum of the expected future undiscounted cash flows from the use of the asset and its eventual disposition is less than the carrying amount of the asset, then an impairment loss is recognized. The impairment loss is measured based on the fair value of the asset. Any resulting impairment is recorded as a reduction in the carrying value of the related asset in excess of fair value and a charge to operations.

Loss Per Share

We report basic and diluted loss per share (“LPS”) for common and common share equivalents. Basic LPS is computed by dividing reported losses by the weighted average shares outstanding. Diluted LPS is computed by adding to the weighted average shares the dilutive effect if stock options and warrants were exercised into common stock. For thethree andnine months ended* September 30, 2025and2024*, the denominator in the diluted LPS computation is the same as the denominator for basic LPS due to the Company’s net loss which creates an anti-dilutive effect of the warrants and stock options. As of* September 30, 2025* the vested stock options available to be exercised totaled 63,781,849 and the vested warrants available to be exercised totaled 28,980,918.

Use of Estimates

The preparation of condensed consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities at the date of the condensed consolidated financial statements, and revenues and expenses during the period reported. Actual results could differ from those estimates. Estimates are used when accounting for stock-based transactions, debt transactions, derivative liabilities, expected credit losses, asset depreciation and amortization, impairment expense, among others.

The methods, estimates and judgments we use in applying these most critical accounting policies have a significant impact on the results of our condensed consolidated financial statements.

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Share-Based Compensation Expense

We recognize compensation expense for stock option awards on a straight-line basis over the applicable service period of the award, which is the vesting period. Fair value is determined on the grant date. Share-based compensation expense is based on the grant date fair value estimated using the Black-Scholes Option pricing model.

For stock and stock options issued to consultants and other non-employees for services, the Company measures and records an expense as of the earlier of the date at which either: a commitment for performance by the non-employee has been reached or the non-employee’s performance is complete. The equity instruments are measured at the current fair value, and for stock options, the instruments are measured at fair value using the Black Scholes Option pricing model.

The following methodology and assumptions were used to calculate share-based compensation for thenine months ended* September 30, 2025* and2024:

Expected price volatility is the measure by which our stock price is expected to fluctuate during the expected term of an option. The expected volatility is derived from the historical daily change in the market price of our common stock, as we believe that historical volatility is the best indicator of future volatility.

The risk-free interest rate used in the Black-Scholes calculation is based on the prevailing U.S. Treasury yield as determined by the U.S. Federal Reserve. We have never paid any cash dividends on our common stock and donot anticipate paying cash dividends on our common stock in the foreseeable future.

Warrants

Warrants issued with our convertible and non-convertible debt instruments are accounted for under the fair value and relative fair value method. The warrant isfirst analyzed per its terms as to whether it has derivative features ornot. If the warrant is determined to be a derivative andnot qualify for equity treatment, then it is measured at fair value using the Black Scholes Option pricing model and recorded as a liability on the condensed consolidated balance sheets. The warrant is re-measured at its then current fair value at each subsequent reporting date (it is “marked-to-market”). If the warrant is determined tonot have derivative features, it is recorded into equity at its fair value using the Black Scholes Option pricing model, however, limited to a relative fair value based upon the percentage of its fair value to the total fair value including the fair value of the convertible note. Convertible debt instruments are recorded at fair value, limited to a relative fair value based upon the percentage of its fair value to the total fair value including the fair value of the warrant. The warrant relative fair values are also recorded as a discount to the convertible promissory notes.

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Non-Cash Transactions

We determine the value assigned to each intangible we acquire, and/or services or products received for non-cash consideration of our common stock based on the market price of our common stock issued as consideration, at the date of the agreement of each transaction or when the service is rendered or product is received.

Revenue Recognition

We account for revenue in accordance with ASC606, “Revenue from Contracts with Customers”. The guidance focuses on the core principle for revenue recognition, which is that an entity should recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. To achieve that core principle, the guidance provides that an entity should apply the following steps:

Step1: Identify the contract(s) with a customer.

Step2: Identify the performance obligations in the contract.

Step3: Determine the transaction price.

Step4: Allocate the transaction price to the performance obligations in the contract.

Step5: Recognize revenue when (or as) the entity satisfies a performance obligation.

The Company’s products are sold through a contract with the customer and a written purchase order, in which the details of the contract are defined including the transaction price and method of shipment. The only performance obligation is to create and ship the product, and each product has separate pricing. Revenue is recognized at a point in time when the goods are shipped if the agreement is FOB manufacturer, and when goods are delivered if FOB destination. Revenue is recognized with a reduction for sales discounts, as appropriate and negotiated in the customer’s purchase order.

Service contracts are performed through a written contract, which specifies the performance obligations and the rate at which the services will be billed, typically by time and materials. Each service is separately negotiated and priced. Revenue is recognized as services are performed and completed, or, for services related to product installations, at the completion of the installation. A few contracts have called for milestone or fixed cost payments, where we invoice an agreed-to amount per month for the life of the contract. In these instances, completed work, billed hourly, is recognized as revenue. If the billing amount is greater or lesser than the completed work, a receivable or payable is created. These accounts are adjusted upon additional billings as the work is completed. To date, there have beenno discounts or other financing terms for the contracts.

As we generate revenues from royalties or license fees from our intellectual property, a licensee will pay a license fee inone or more installments and ongoing royalties based on their sales of products incorporating or using our licensed intellectual property. We have entered into a licensing agreement for the CupriDyne Clean product, and we recognize royalty and license fees on a quarterly basis as the product is sold through tothird parties and reported to us.

Our Canadian subsidiary had a grant deposit outstanding at* September 30, 2025* and* December 31, 2024*, totaling $79,000 and $76,000. These were awarded as part of a grant for a particular project that has been delayed. ONM Environmental had a customer deposit outstanding at* September 30, 2025* and* December 31, 2024*, totaling $1,000 and $14,000 related to customer purchase ordersnot yet fulfilled.

Government Grants

We have been awarded multiple research grants from the private and public Canadian research programs. The income we receive directly from grants is recorded as other income. We have been awarded over90 grants since ourfirst in2015. Some of the funds from these grants are given directly tothird parties (such as the University of Alberta or athird-party research scientist) to support research on our technology. The grants have terms generally ranging betweensix andeighteen months and support a majority, butnot all, of the related research budget costs. This cooperative research allows us to utilize (i) a depth of resources and talent to accomplish highly skilled work, (ii) financial aid to support research and development costs, (iii) independent and credible validation of our technical claims.

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The grants typically provide for (i) recurring monthly amounts, (ii) reimbursement of costs for research talent for which we invoice to request payment, and (iii) ancillary cost reimbursement for research talent travel related costs. All awarded grants have specific requirements on how the money is spent, typically to employ researchers.None of the funds* maybe used for general administrative expenses or overhead in the United States. These grants have substantially increased our level of research and development activities in Canada. We continue to apply for Canadian government and agency grants to fund research and development activities.Not all of our grant applications have been awarded, andno* assurance can be made that any pending grant application, or any future grant applications, will be awarded.

Income Taxes

The asset and liability approach is used to recognize deferred tax assets and liabilities for the expected future tax consequences of temporary differences between the carrying amounts and the tax bases of asset and liabilities. Deferred tax assets and liabilities are determined based on the differences between financial reporting and tax bases of assets and liabilities and are measured using the enacted tax rates and laws that will be in effect when the differences are expected to reverse. The effect on deferred tax asset and liabilities of a change in tax rates is recognized in income in the period that includes the enactment date.

We account for uncertainties in income tax law under a comprehensive model for the financial statement recognition, measurement, presentation, and disclosure of uncertain tax positions taken or expected to be taken in income tax returns as prescribed by GAAP. Under GAAP, the tax effects of a position are recognized only if it is “more-likely-than-not” to be sustained by the taxing authority as of the reporting date. If the tax position isnot considered “more-likely-than-not” to be sustained, thenno benefits of the position are recognized. Management believes there areno unrecognized tax benefits or uncertain tax positions as of* September 30, 2025* and* December 31, 2024*.

The Company assessed its earnings history, trends and estimates of future earnings and determined that the deferred tax asset couldnot be realized as of* September 30, 2025* and* December 31, 2024*. Accordingly, a100% valuation allowance was recorded against the net deferred tax asset.

The Company recognizes interest and penalties on income taxes as a component of income tax expense, should such an expense be realized.

Fair Value of Financial Instruments

Management believes the carrying amounts of the Company’s financial instruments as of* September 30, 2025* and* December 31, 2024* approximate their respective fair values because of the short-term nature of these instruments. Such instruments consist of cash, accounts receivable, note receivable, accounts payable, and debt obligations. The carrying amount of debt instruments are believed to approximate fair value as the stated interest rates are reflective of the prevailing market rates.

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Leases

At inception of a lease contract, we assess whether the contract is, or contains, a lease. Our assessment is based on: (1) whether the contract involves the use of a distinct identified asset, (2) whether we obtain the right to substantially all the economic benefit from the use of the asset throughout the period of the contract, and (3) whether we have the right to direct the use of the asset during such time period. At inception of a lease, we allocate the consideration in the contract to each lease component based on its relative stand-alone price to determine the lease payments. Leases are classified as either finance leases or operating leases. A lease must be classified as a finance lease if any of the following criteria are met: the lease transfers ownership of the asset by the end of the lease term, the lease contains an option to purchase the asset that is reasonably certain to be exercised, the lease term is for a major part of the remaining useful life of the asset or the present value of the lease payments equals or exceeds substantially all of the fair value of the asset. A lease is classified as an operating lease if it doesnot meet any of these criteria. We haveone lease classified as a finance lease. For all leases at the lease commencement date, a right-of-use asset and a lease liability are recognized. The right-of-use asset represents the right to use the leased asset for the lease term. The lease liability represents the present value of the lease payments under the lease. The right-of-use asset is initially measured at cost, which primarily comprises the initial amount of the lease liability, plus any initial direct costs incurred, consisting mainly of brokerage commissions, less any lease incentives received. All right-of-use assets are reviewed for impairment. The lease liability is initially measured at the present value of the lease payments, discounted using the interest rate implicit in the lease or, if that rate cannot be readily determined, management estimates the incremental borrowing rate, which currently is estimated to be 18%. Lease payments included in the measurement of the lease liability comprise the following: the fixed noncancelable lease payments, payments for optional renewal periods where it is reasonably certain the renewal period will be exercised, and payments for early termination options unless it is reasonably certain the lease willnot be terminated early. Lease components are included in the measurement of the initial lease liability. Additional payments based on a change in our portion of the operating expenses, including real estate taxes and insurance, are recorded as a period expense when incurred. Lease modifications result in remeasurement of the lease liability. Lease expense for operating leases consists of the lease payments plus any initial direct costs, primarily brokerage commissions, and is recognized on a straight-line basis over the lease term. We have electednot to recognize right-of-use assets and lease liabilities for short-term leases that have a term of12 months or less. The effect of short-term leases on our right-of-use asset and lease liability wasnot material. As of* September 30, 2025* and* December 31, 2024*, the operating right-of-use assets totaled $1,070,000, and $992,000, respectively. As of* September 30, 2025* and* December 31, 2024*, the operating lease liability totaled $1,111,000 and $1,027,000, respectively, on our condensed consolidated balance sheets related to our operating leases. The finance lease is related to Clyra. As of* September 30, 2025* and* December 31, 2024*, the finance right-of-use asset for Clyra totaled $400,000 and $451,000 and the finance lease liability totaled $383,000 and $448,000, respectively, on our condensed consolidated balance sheets related to our finance lease.

Equipment and Leasehold Improvements

Equipment and leasehold improvements are stated at cost less accumulated depreciation. Depreciation is computed using the straight-line method over the estimated useful lives of the assets, which range from 3 -10 years. Additions, renewals, and betterments that significantly extend the life of the asset are capitalized. Expenditures for repairs and maintenance are charged to expense as incurred. For assets sold or otherwise disposed of, the cost and related accumulated depreciation and amortization are removed from the accounts, and any related gain or loss is reflected in operations for the period.

Noncontrolling Interest

A noncontrolling interest is defined as the portion of the equity in an entitynot attributable, directly or indirectly, to the primary beneficiary. Noncontrolling interests are required to be presented as a separate component of equity on a condensed consolidated balance sheets. Accordingly, the presentation of net loss is modified to present the loss attributed to controlling and non-controlling interests. The noncontrolling interest on the Company’s condensed consolidated balance sheets represents equitynot held by the Company. In accordance with ASC810-10-20, “Noncontrolling Interests” BioLargo consolidatesthree non-wholly owned subsidiaries - Clyra, BLEST and BETI. Noncontrolling interest of Clyra represents 52% and 48% as of* September 30, 2025* and* December 31, 2024*. Noncontrolling interest of BLEST represents 26% as of* September 30, 2025* and* December 31, 2024*. Noncontrolling interest of BETI represents 4% as of* September 30, 2025*, and* December 31, 2024*.

Recent Accounting Pronouncements

In* December 2023,the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”)2023-09, “Improvements to Income Tax Disclosures.” ASU2023*-09 requires disclosure of specific categories in the income tax rate reconciliation and requires additional information for reconciling items that meet a quantitative threshold. The standard requires an annual disclosure of income taxes paid, net of refunds received, disaggregated by federal, state and foreign taxes and to disaggregate the information by jurisdiction based on a quantitative threshold. The standard is effective for fiscal years beginning after* December 15, 2024and early adoption is permitted. The adoption of the standard didnot* have a material impact on the Company's disclosures.

In* November 2024,the FASB issued ASU2024*-03, “Expense Disaggregation Disclosures.” ASU2024-03 requires disclosure to disaggregate prescribed expenses within relevant income statement captions. The standard is effective for fiscal years beginning after* December 15, 2026,and for interim periods after December 15, 2027.*Early adoption is permitted. The Company is evaluating the impact of the changes to its existing disclosures.

In* July 2025,the FASB issued ASUNo.* 2025-05, Financial Instruments – Credit Losses (Topic326): Measurement of Credit Losses for Accounts Receivable and Contract Assets The ASU provides an optional practical expedient for estimating future credit losses based on current conditions as of the balance sheet date and assuming those conditions donot change over the remaining life of the accounts receivable. This standard is effective for the Company on* January 1, 2026.*The Company is currently evaluating this ASU impact on the condensed consolidated results of operations and financial condition.

In* September 2025,the FASB issued ASUNo.* 2025-06, Intangibles - Goodwill and Other - Internal-Use Software (Subtopic350-40): Targeted Improvements to the Accounting for Internal-Use Software. The ASU removes references to prescriptive software development stages and includes an updated framework for capitalizing internal software costs. This standard is effective for the Company on* January 1, 2028.*The Company is currently evaluating this ASU’s impact on the condensed consolidated results of operations and financial condition.

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Note3. Sale of Stock for Cash

Lincoln Park Financing

On* December 13, 2022,we entered into a stock purchase agreement (the “LPC Purchase Agreement”) with Lincoln Park Capital Fund, LLC ("Lincoln Park"), pursuant to which Lincoln Park agreed to purchase from us at our request up to an aggregate of $10,000,000 of our common stock (subject to certain limitations) from time to time over a period ofthree* years. The agreement allows us, at our sole discretion, to direct Lincoln Park to purchase shares of our common stock, subject to limitations in both volume and dollar amount. The purchase price of the shares that* maybe sold to Lincoln Park under the agreement is the lower of (i) the lowest sale price on the date of purchase, or (ii) the average of thethree* lowest closing prices in the prior12 business days. There areno restrictions on future financings, rights offirst refusal, participation rights, penalties, or liquidated damages other than a prohibition on entering into a “Variable Rate Transaction,” as defined in the agreement. Concurrently with the LPC Purchase Agreement, we entered into a Registration Rights Agreement, pursuant to which we filed a registration statement on Form S-1 with the SEC on* December 23, 2022.This registration statement was declared effective on January 19, 2023.*

During thethree andnine months ended* September 30, 2025* we sold 4,222,467 and 8,299,752 shares of our common stock and received $764,000 and $1,587,000 in gross and net proceeds.

We didnot sell any shares of our common stock during thethree months ended* September 30, 2024.During thenine* months ended* September 30, 2024,*we sold 766,175 shares of our common stock and received $260,000 in gross and net proceeds.

Unit Offerings

We didnot sell shares of our common stock in Unit Offerings duringthree nine months ended* September 30, 2025*.

We didnot sell shares of our common stock in Unit Offerings during thethree months ended* September 30, 2024.During thenine* months ended* September 30, 2024,we sold 1,848,720 shares of our common stock and received $419,000 in gross and $349,000 in net proceeds fromseven* accredited investors. In addition to the shares, we issued each investor asix-month and afive-year warrant to purchase additional shares. (See Note6, “Warrants Issued in Unit Offering”.)

Note4. Debt Obligations

The following table summarizes our debt obligations outstanding as of* September 30, 2025* and* December 31, 2024* (in thousands). The table doesnot include debt obligations of our partially owned subsidiary Clyra Medical (see Note8, “Debt Obligations of Clyra Medical”).

For thethree andnine months ended* September 30, 2025*, we recorded $144,000 and $352,000 of interest expense related to the coupon interest from our debt obligations, inclusive of Clyra Medical debt obligations.

For thethree andnine months ended* September 30, 2024*, we recorded $14,000 of interest income and $34,000 of interest expense related to the coupon interest from our debt obligations, inclusive of Clyra Medical debt obligations.

Vehicle loan

On* February 7, 2023,we entered a loan agreement with Bank of America for the purchase of a commercial vehicle used in operations totaling $80,000, at 5.29% annual interest which matures March 7, 2029.The loan agreement requires monthly payments of $1,000. As of September 30, 2025*, and* December 31, 2024,*the balance of this loan totals $45,000 and $54,000.

Term Loan

On* April 5, 2025,we entered a term loan agreement with American Express for working capital in the principal amount of $50,000, at 7.98% annual interest, which matures April 10, 2028,and requires monthly payments of $2,000. As of September 30, 2025*, the balance of this loan totals $44,000.

SBA Program Loans

On* June 3, 2020,ONM Environmental received a $217,000 CARES Act Paycheck Protection Program loan from the SBA. On February 7, 2022,it received notice that the SBA had forgiven $174,000 of the loan. ONM Environmental requested reconsideration of the partial-forgiveness determination. As of the date of this report, the SBA hasnot* made a final determination on forgiveness, andno payments are required. As of* September 30, 2025*, and* December 31, 2024,*the outstanding balance on this loan totaled $43,000.

In* July 2020,ONM Environmental received an Economic Injury Disaster Loan (EIDL) from the SBA in the amount of $150,000. The note has a 3.75% annual interest rate, requires monthly payments of $700, and matures July 2053.As of September 30, 2025*, and* December 31, 2024,*the balance of this loan totaled $141,000 and $144,000, respectively.

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Note5. Share-Based Compensation

Issuance of Common Stock in exchange for Services

Payment of Officer Salaries

On* September 30, 2025*, we issued 177,235 shares of our common at $0.17 per share in lieu of $30,000 of accrued and unpaid obligations totwo officers. On* June 30, 2025,we issued 350,751 shares of our common at $0.21 per share in lieu of $70,000 of accrued and unpaid obligations totwo* officers. On* March 31, 2025,*we issued 11,250 shares of our common at $0.28 per share in lieu of $3,000 of accrued and unpaid obligations to an officer.

On* September 30, 2024,an officer agreed to convert an aggregate $9,000 of accrued and unpaid salary into 41,087 shares of our common stock at $0.23 per share. There wereno shares of our common stock issued in exchange for unpaid salary during thethree* months ended* June 30, 2024,or March 31, 2024.*

Payment of Consultant and Vendor Fees

During thethree months ended* September 30, 2025*, we issued 147,059 shares of our common at $0.17 per share in lieu of $25,000 of accrued and unpaid obligations to consultants and vendors. On* June 30, 2025,we issued 564,252 shares of our common at $0.21 per share in lieu of $143,000 of accrued and unpaid obligations to consultants and vendors. During thethree* months ended* March 31, 2025,*we issued 209,080 shares of our common at $0.28 per share in lieu of $58,000 of accrued and unpaid obligations to consultants and vendors.

On* September 30, 2024,we issued 219,816 shares of our common stock at $0.23 per share in lieu of $54,000 of accrued and unpaid obligations to consultants and vendors. On June 30, 2024,we issued 446,989 shares of our common stock at $0.26 per share in lieu of $116,000 of accrued and unpaid obligations to consultants and vendors. On March 31, 2024,*we issued 288,997 shares of our common stock at $0.35 per share in lieu of $83,000 of accrued and unpaid obligations to consultants and vendors.

All of these offerings and sales were made in reliance on the exemption from registration contained in Section4(2) of the Securities Exchange Act and/or Regulation D promulgated thereunder asnot involving a public offering of securities.

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Stock Option Expense

During thethree andnine months ended* September 30, 2025*, we recorded an aggregate $844,000 and $1,951,000, and during thethree andnine months ended* September 30, 2024*, we recorded an aggregate $237,000, and $1,264,000, in selling general and administrative expense related to the issuance of stock options. We issued options through our2024 Equity Incentive Plan, our2018 Equity Incentive Plan, and outside of these plans. Included in these totals is option expense related to issuances by our subsidiary, Clyra Medical, totaling $193,000 and $599,000 in thethree andnine months ended* September 30, 2025*, and $43,000 and $165,000 in thethree andnine months ended* September 30, 2024*. (See Note8.)

2024 Equity Incentive Plan

On* June 13, 2024,our stockholders adopted the BioLargo2024* Equity Incentive Plan (“2024 Plan”) as a means of providing our directors, key employees, and consultants additional incentive to provide services. Both stock options and stock grants* maybe made under this plan for a period of 10 years. It is set to expire on its terms on June 13, 2034.Our Board of Director’s Compensation Committee administers this plan. As plan administrator, the Compensation Committee has sole discretion to set the price of the options. The plan authorizes the following types of awards: (i) incentive and non-qualified stock options, (ii) restricted stock awards, (iii) stock bonus awards, (iv) stock appreciation rights, (v) restricted stock units, and (vi) performance awards. The number of shares available to be issued under the2024* Plan increases automatically on* January 1of each year by the lesser of (a)2 million shares, or (b) such number of shares determined by our Board. As of September 30, 2025*,42,000,000 shares are authorized under the plan, and 27,520,544 remain available for grant.

Activity for our stock options under the2024 Plan during thenine months ended* September 30, 2025*, and2024, is as follows:

The options granted to purchase 8,985,536 shares during thenine months ended* September 30, 2025* with an aggregate fair value of $1,577,000 were issued to board of directors, employees and consultants: (i) we issued options to purchase 1,241,688 shares of our common stock to members of our board of directors for services performed, in lieu of cash; the fair value of these options totaled $235,000; (ii) we issued options to purchase 4,907,811 shares of our common stock to employees as part of employee retention plans; the fair value of employee retention plan options totaled $793,000 and vest over time or based on performance metrics; (iii) we issued options to purchase 2,536,037 shares of our common stock to consultants in lieu of cash for expiring options and for services performed; the fair value of these options totaled $482,000 and (iv) we issued options to purchase 300,000 shares of our common stock to our Chief Financial Officer with a fair value of $67,000 for expiring options. All stock option expense is recorded on our condensed consolidated statement of operations as selling, general and administrative expense.

As of* September 30, 2025*, there remains $735,000 of stock option expense to be expensed over the next four years.

The options granted to purchase 3,482,270 shares during thenine months ended* September 30, 2024*with an aggregate fair value of $782,000 were issued to board of directors, employees and consultants: (i) we issued options to purchase 771,180 shares of our common stock to members of our board of directors for services performed, in lieu of cash; the fair value of these options totaled$171,000; (ii) we issued options to purchase 1,013,474 shares of our common stock to employees as part of employee retention plans; the fair value of employee retention plan options totaled $154,000 and vest over time or based on performance metrics; (iii) we issued options to purchase 697,616 shares of our common stock to consultants in lieu of cash for expiring options and for services performed; the fair value of these options totaled $223,000 and (iv) we issued options to purchase 1,000,000 shares of our common stock to our Chief Financial Officer with a fair value of $234,000 for expiring options. All stock option expense is recorded on our condensed consolidated statement of operations as selling, general and administrative expense.

Extension of Agreement with Chief Financial Officer

On* January 31, 2025,the Engagement Agreement with our Chief Financial Officer Charles K. Dargan, II automatically extended for aone-year period to expire January 31, 2026 (the“2025*-26 Term”). As the sole compensation for the2025-26 Term, Mr. Dargan was issued an option (“Option”) to purchase 300,000 shares of the Company’s common stock. The Option vests over the period of the extended term in monthly installments of 25,000 shares, so long as the agreement is in full force and effect. The Option is exercisable at $0.2536 per share, the closing price of BioLargo’s common stock on the last trading day of* January 2025,expiresten years from the grant date, and was issued pursuant to the Company’s2024* Equity Incentive Plan.

On* August 13, 2024,we and our Chief Financial Officer Charles K. Dargan, II agreed to extend the term of his engagement agreement dated February 1, 2008 (the “Engagement Agreement”, which had been previously extended multiple times), pursuant to which Mr. Dargan has been and continues to serve as our Chief Financial Officer. The Engagement Extension Agreement dated as August 13, 2024 (the “Engagement Extension Agreement”) expired January 31, 2025 (the “Extended Term”), at which time the agreement will automatically renew for subsequentone-year periods. As the sole compensation for the Extended Term, Mr. Dargan was issued an option (“Option”) to purchase 300,000 shares of the Company’s common stock. The Option vests over the period of the Extended Term in monthly installments of 25,000 shares, so long as the agreement is in full force and effect. The Option is exercisable at $0.24 per share, the closing price of BioLargo’s common stock on the August 13, 2024grant date, expiresten years from the grant date, and was issued pursuant to the Company’s2024* Equity Incentive Plan. The Option is Mr. Dargan’s sole compensation for the Extended Term. As was the case in all prior terms of his engagement, there isno cash component of his compensation for the Extended Term. Mr. Dargan is eligible to be reimbursed for business expenses he incurs in connection with the performance of his services as the Company’s Chief Financial Officer (although he has madeno such requests for reimbursement in the past). All other provisions of the Engagement Agreementnot expressly amended pursuant to the Engagement Extension Agreement remain the same, including provisions regarding indemnification and arbitration of disputes. Upon each renewal of the agreement, Mr. Dargan will be issued an option to purchase 300,000 shares, at an exercise price equal to the closing price of the Company's common stock on the prior business day, vesting overone year.

2018 Equity Incentive Plan

On* June 22, 2018,our stockholders adopted the BioLargo2018* Equity Incentive Plan (“2018 Plan”) as a means of providing our directors, key employees, and consultants additional incentive to provide services. Both stock options and stock grants* maybe made under this plan for a period of 10 years. It is set to expire on its terms on June**22,* 2028. Our Board of Director’s Compensation Committee administers this plan. As of* June 30, 2024,the2018* Plan closed to further stock option grants. The2018 Plan closed with 9,343,614 shares unissued.

Activity for our stock options under the2018 Plan during thenine months ended* September 30, 2025*, and2024, is as follows:

(1) – Aggregate intrinsic value based on closing common stock price of $0.17 at* September 30, 2025*

During thenine months ended* September 30, 2025*, an option holder elected to exercise 566,951 options using the cashless exercise option in exchange for 265,800 shares of our common stock.

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As of* September 30, 2025*, there remains $382,000 of stock option expense to be expensed over the nexttwo years.

The options granted to purchase 1,547,938 shares during thenine months ended* September 30, 2024*with an aggregate fair value of $418,000 were issued to board of directors, employees and consultants: (i) we issued options to purchase 267,746 shares of our common stock to members of our board of directors for services performed, in lieu of cash; the fair value of these options totaled$85,000; (ii) we issued options to purchase 735,351 shares of our common stock to employees as part of employee retention plans; the fair value of employee retention plan options totaled $160,000 and vest over time or based on performance metrics; and (iii) we issued options to purchase 544,841 shares of our common stock to replace expiring options; the fair value of these options totaled $173,000. All stock option expense is recorded on our consolidated statement of operations as selling, general and administrative expense.

2007 Equity Incentive Plan

On* September**7,* 2007, and as amended* April 29, 2011,the BioLargo, Inc.2007 Equity Incentive Plan (“2007* Plan”) was adopted as a means of providing our directors, key employees and consultants additional incentive to provide services. Both stock options and stock grants* maybe made under this plan for a period of 10 years, which expired on September 7, 2017.The Board’s Compensation Committee administers this plan. As plan administrator, the Compensation Committee has sole discretion to set the price of the options. As of September 2017,*the Plan was closed to further stock option grants.

Activity for our stock options under the2007 Plan for thenine months ended* September 30, 2025* and2024 is as follows:

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Non-Plan Options

Activity of our non-plan stock options issued for thenine months ended* September 30, 2025* and2024 is as follows:

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During thenine months ended* September 30, 2025*, we issued options to purchase an aggregate 32,143 shares of our common stock at $0.28 per share to vendors for fees for services. The fair value of the options issued totaled an aggregate $8,000 and is recorded in our selling, general and administrative expense. As of* September 30, 2025*, there remains $55,000 of stock option expense to be expensed over the nextone year.

During thenine months ended* September 30, 2024,*we issued options to purchase an aggregate 85,251 shares of our common stock to vendors for fees for services. The fair value of the options issued totaled an aggregate $18,000 and is recorded in our selling, general and administrative expense.

During thenine months ended* September**30,* 2024, investors exercised stock options and we received $153,000 of proceeds and issued 463,882 shares of our common stock.