2. Summary of significant accounting policies

The significant accounting policies and estimates used in preparation of the condensed consolidated financial statements are described in the Company’s audited consolidated financial statements as of and for the year ended December 31, 2024, and the notes thereto, which are included in the Company’s Annual Report on Form 10-K for the year ended  December 31, 2024, as filed with the Securities and Exchange Commission, or the SEC, on March 31, 2025. There have been no material changes in the Company’s significant accounting policies during the three and nine months ended September 30, 2025.

Basis of presentation

The accompanying unaudited condensed consolidated financial statements of Aqua Metals, Inc. and subsidiaries (collectively, the “Company” or “Aqua Metals”) have been prepared in accordance with the interim reporting requirements of Form 10-Q, pursuant to the rules and regulations of the United States Securities and Exchange Commission (the “SEC”) and should be read in conjunction with the Company's audited consolidated financial statements for the period ended December 31, 2024, which are included on Form 10-K filed with the Securities and Exchange Commission on March 31, 2025. Accordingly, they do not include all the information and footnotes required by generally accepted accounting principles in the United States of America (“U.S. GAAP”) for annual consolidated financial statements. 

In the opinion of management, all adjustments (which include normal recurring adjustments) considered necessary to present fairly each of the condensed consolidated balance sheet as of September 30, 2025, the condensed consolidated statements of operations for the three and nine months ended September 30, 2025 and September 30, 2024, the condensed consolidated statements of stockholders' equity for the three and nine months ended September 30, 2025 and September 30, 2024 and the condensed consolidated statements of cash flows for the nine months ended September 30, 2025 and September 30, 2024, as applicable, have been made. The condensed consolidated balance sheet as of December 31, 2024 has been derived from the Company’s audited consolidated financial statements as of such date, but it does not include all disclosures required by U.S. GAAP for annual presentation.

The results of operations for the three and nine months ended September 30, 2025 are not necessarily indicative of results that may be expected for the year ending  December 31, 2025.

Principles of consolidation

The accompanying unaudited condensed consolidated financial statements include the accounts of the Company and its subsidiaries, all of which are wholly-owned subsidiaries. Inter-company accounts and transactions have been eliminated in consolidation.

Use of estimates

The preparation of the consolidated financial statements requires management of the Company to make a number of estimates and assumptions relating to the reported amount of assets and liabilities and the disclosure of contingent assets and liabilities at the date of the consolidated financial statements, and the reported amounts of expenses during the period. Significant items subject to such estimates and assumptions include the carrying amount and valuation of long-lived assets, valuation allowances for deferred tax assets, the determination of stock option expense and the determination of the fair value of stock warrants issued. Actual results could differ from those estimates.

Fair value measurements

The carrying amounts of cash and cash equivalents, accounts receivable, inventory, prepaid expenses and other current assets, accounts payable, and accrued expenses approximate fair value due to the short-term nature of these instruments. The carrying value of short and long-term debt, and lease liabilities also approximates fair value since these instruments bear market rates of interest or are calculated using market rates of interest. None of these instruments are held for trading purposes.

Fair value is defined as an exit price, representing the amount that would be received upon the sale of an asset or payment to transfer a liability in an orderly transaction between market participants. Fair value is a market-based measurement that is determined based on assumptions that market participants would use in pricing an asset or liability. A three-tier fair value hierarchy is used to prioritize the inputs in measuring fair value as follows:

Level 1. Quoted prices in active markets for identical assets or liabilities.

Level 2. Quoted prices for similar assets and liabilities in active markets, quoted prices for identical or similar assets or liabilities in markets that are not active, or other inputs that are observable, either directly or indirectly.

Level 3. Significant unobservable inputs that cannot be corroborated by market data.

The asset or liability’s fair value measurement within the fair value hierarchy is based upon the lowest level of any input that is significant to the fair value measurement.

As of  September 30, 2025 and  December 31, 2024, the Company had a Level 3 warrant liability related to freestanding warrants issued in connection with a private placement transaction that is measured at fair value on a recurring basis.

Net loss per share

Basic net loss per share is computed by dividing net loss by the weighted average number of common shares outstanding during the period. Diluted net loss per share is computed by dividing the net loss by the weighted average number of common share equivalents outstanding for the period determined using the treasury-stock method or the if-converted method, as applicable. For purposes of this calculation, stock options, restricted stock units (RSUs) and warrants to purchase common stock are considered to be common stock equivalents and are only included in the calculation of diluted net loss per share when their effect is dilutive. The following shares underlying outstanding convertible notes, stock options, RSUs and warrants to purchase common stock were anti-dilutive due to a net loss in the periods presented and, therefore, were excluded from the dilutive weighted average securities computation for the nine months ended September 30, as indicated below:

Segment and geographic information

Our chief operating decision maker (“CODM”) is the Chief Executive Officer. Operating segments are defined as components of an enterprise engaging in business activities for which discrete financial information is available and regularly reviewed by the CODM in deciding how to allocate resources and in assessing performance. The CODM views its operations and manages its business in one operating segment. For further discussion related to segment reporting, please refer to Note 14 - Segment reporting.

Concentration of credit risk

The Company did not generate revenue during the three and nine months ended September 30, 2025 and 2024, respectively. The Company had no trade receivables as of  September 30, 2025 and  December 31, 2024.

Recent accounting pronouncements

Recently issued accounting pronouncements not yet adopted

In  November 2024, the FASB issued ASU 2024-03, Income Statement—Reporting Comprehensive Income—Expense Disaggregation Disclosures (Subtopic 220-40): Disaggregation of Income Statement Expenses, which introduced new guidance on disclosures of specified information about certain costs and expenses included within expenses presented on the face of the income statements, such as purchases of inventory and employee compensation. This guidance is effective for the Company for annual reporting periods beginning  January 1, 2027 and interim reporting periods beginning  January 1, 2028. The Company is currently evaluating the impact that the adoption of this pronouncement will have on the Company's consolidated financial statements and disclosures. 

In  December 2023, the FASB issued ASU No. 2023-09, Improvements to Income Tax Disclosures (Topic 740). The ASU requires disaggregated information about a reporting entity’s effective tax rate reconciliation as well as additional information on income taxes paid. The ASU is effective on a prospective basis for annual periods beginning after  December 15, 2024. Early adoption is also permitted for annual financial statements that have not yet been issued or made available for issuance. This ASU will result in the required additional disclosures being included in our consolidated financial statements, once adopted.

In September 2025, the Financial Accounting Standards Board (“FASB”) issued ASU 2025-06, Intangibles — Goodwill and Other — Internal-Use Software (Subtopic 350-40): Targeted Improvements to the Accounting for Internal-Use Software. The ASU amends certain aspects for the accounting and disclosure of internal-use software by replacing prescriptive project-stage guidance with a principles-based capitalization model that applies to all development approaches. Capitalization begins when management authorizes and commits to fund a project and it is probable the software will be completed and used as intended, while development uncertainty defers capitalization until resolved. The ASU also integrates website-development guidance, aligns software disclosures with those for property, plant and equipment. The amendments are effective for fiscal years beginning after December 15, 2027, including interim periods, with early adoption permitted. The Company is evaluating the impact of this ASU and does not expect a material effect on its consolidated financial statements upon adoption.