Nautilus Biotechnology, Inc.

Nautilus Biotechnology, Inc.Notes to Consolidated Financial Statements

1. Description of Business and Basis of Presentation

Nautilus Biotechnology, Inc. (the “Company”) is a biotechnology company incorporated in 2016 with corporate headquarters in Seattle, Washington and research and development headquarters in San Carlos, California. Since the Company’s incorporation in 2016, the Company has devoted substantially all of its resources to research and development activities, including with respect to its proteomics platform, business planning, establishing and maintaining its intellectual property portfolio, hiring personnel, raising capital and providing general and administrative support for these operations.

On June 9, 2021, Nautilus Biotechnology, Inc. a Delaware corporation (f/k/a ARYA Sciences Acquisition Corp. III, a Cayman Islands exempted company and the Company’s predecessor company (“ARYA”)), consummated the business combination (the “Business Combination”) pursuant to the terms of that certain Business Combination Agreement, dated as of February 7, 2021 (the “BCA”), by and among ARYA, Mako Merger Sub, Inc., a Delaware corporation and wholly-owned subsidiary of ARYA (“Mako Merger Sub”), and Nautilus Subsidiary, Inc., a Delaware corporation (f/k/a Nautilus Biotechnology, Inc.) (“Legacy Nautilus”). As a result of the Business Combination, ARYA changed its name to “Nautilus Biotechnology, Inc.” and Mako Merger Sub merged with and into Legacy Nautilus with Legacy Nautilus surviving as the surviving company and becoming a wholly-owned subsidiary of ARYA (the “Merger” and, collectively with the other transactions described in the BCA, the “Reverse Recapitalization”).

In addition, in conjunction with the completion of the Business Combination, certain investors (“PIPE Investors”) subscribed for the purchase of an aggregate of 20,000,000 shares of common stock of the Company (“New Nautilus Common Stock”) at a price of $10.00 per share for aggregate gross proceeds of $200.0 million (“PIPE Financing”).

Basis of Presentation

The consolidated financial statements and accompanying notes were prepared in accordance with accounting principles generally accepted in the United States of America (“U.S. GAAP”) and regulations of the U.S. Securities and Exchange Commission. The accompanying financial statements are consolidated for the years ended December 31, 2025 and 2024 and include the accounts of Nautilus Biotechnology, Inc. and its wholly-owned subsidiary, Nautilus Subsidiary, Inc. All intercompany transactions and balances have been eliminated upon consolidation. The Company’s reporting currency is the U.S. dollar. Certain prior year amounts have been reclassified to conform to the current year presentation on the statements of cash flows and had no material impact.

Liquidity and Capital Resources

The Company’s consolidated financial statements have been prepared on the basis of continuity of operations, the realization of assets, and the satisfaction of liabilities in the ordinary course of business. Since inception, the Company has been engaged in developing its technology, raising capital, and recruiting personnel. The Company’s operating plan may change as a result of many factors currently unknown and there can be no assurance that the current operating plan will be achieved in the time frame anticipated by the Company, and it may need to seek additional funds sooner than planned. If adequate funds are not available to the Company on a timely basis, it may be required to delay, limit, reduce, or terminate certain commercial efforts, or pursue merger or acquisition strategies, all of which could adversely affect the holdings or the rights of the Company’s stockholders. The Company has incurred net operating losses and negative cash flows from operations in every year since inception and expects this to continue for the foreseeable future. As of December 31, 2025, the Company had an accumulated deficit of $332.0 million.

The Company has funded its operations primarily with proceeds from the issuance of redeemable convertible preferred stock and common stock. In June 2021, the Company received gross proceeds of approximately $345.5 million from PIPE Investors and the Business Combination offset by approximately $18.2 million of transaction costs and underwriters’ fees relating to the closing of the Business Combination. The Company had cash, cash equivalents, and short-term investments of $103.4 million as of December 31, 2025. As of the date on which these consolidated financial statements were issued, the Company believes that its cash, cash equivalents, and short-term

Nautilus Biotechnology, Inc.Notes to Consolidated Financial Statements—(Continued)

investments will be sufficient to fund its operations for at least the next twelve months following the issuance of the consolidated financial statements. The Company’s actual results and its near and long-term future capital requirements will depend on many factors, including its growth rate and the timing and extent of spending to support its research and development efforts. The Company will be required to seek additional equity or debt financing to fund future operations. Future liquidity and cash requirements will depend on numerous factors. In the event that additional financing is required, the Company may not be able to raise it on acceptable terms or at all. If the Company is unable to raise additional capital when desired, or if it cannot expand its operations or otherwise capitalize on its business opportunities because it lacks sufficient capital, its business, operating results, and financial condition would be adversely affected.

2. Significant Accounting Policies

Use of Estimates

The preparation of the consolidated financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosures of contingent assets and liabilities as of the date of the consolidated financial statements, and the reported amounts of expenses during the reporting period. Actual results could differ from those estimates. Significant estimates include determining the estimated lives of property and equipment, stock-based compensation, research and development accruals, loss contingency accruals, and the valuation allowance for deferred tax assets. These estimates and assumptions are based on management’s best estimates and judgment. Management evaluates its estimates and assumptions on an ongoing basis using historical experience and other factors, including the current economic environment, which management believes to be reasonable under the circumstances. The Company adjusts such estimates and assumptions when facts and circumstances dictate. Changes in those estimates resulting from continuing changes in the economic environment will be reflected in the financial statements in future periods. As future events and their effects cannot be determined with precision, actual results could materially differ from those estimates and assumptions.

Concentrations of Credit Risk and Other Risks and Uncertainties

Credit risk represents the accounting loss that would be recognized as of the reporting date if counterparties failed to perform as contracted.

Financial instruments, which potentially subject the Company to concentration of credit risk, consist of cash balances maintained in excess of federal depository insurance limits and investments in marketable debt securities that are not federally insured. The Company has not experienced any losses in such accounts and believes it is not exposed to significant credit risk on cash or investments. The Company relies, and expects to continue to rely, on a number of vendors to provide services, supplies and materials related to its research and development programs. The Company relies on single source suppliers for certain components and materials used in the Nautilus Voyager TMplatform. The loss of any of these single source suppliers would require the Company to expend significant time and effort to locate and qualify an alternative source of supply for these components. The Company also relies, and expects to continue to rely, on third-party manufacturers and, in many cases, single third-party manufacturers for the production of certain reagents and antibodies. These programs could be adversely affected by a significant interruption in these services or the availability of materials.

The Company is subject to risks similar to those of pre-clinical stage companies in the biopharmaceutical industry, including dependence on key individuals, the need to develop commercially viable products, competition from other companies, many of whom are larger and better capitalized, the impact of negative global and national events and the need to obtain adequate additional financing to fund the development of its products. There can be no assurance that the Company’s research and development will be successfully completed, that adequate protection for the Company’s intellectual property will be maintained, that any products developed will obtain required regulatory

Nautilus Biotechnology, Inc.Notes to Consolidated Financial Statements—(Continued)

approval or that any approved products will be commercially viable. Even if the Company’s development efforts are successful, it is uncertain when, if ever, the Company will generate significant revenue from the sale of its products.

Segment Reporting

Operating segments are defined as components of an entity where discrete financial information is evaluated regularly by the chief operating decision maker (“CODM”) in deciding how to allocate resources and in assessing performance. The Company’s Chief Executive Officer is its CODM. The Company’s CODM reviews financial information presented on a consolidated basis for the purposes of making operating decisions, allocating resources and evaluating financial performance. As such, the Company has determined that it operates inone operating andone reportable segment. The Company’s long-lived assets are entirely based in the United States.

Cash and Cash Equivalents

The Company considers all highly-liquid investments with an original maturity of three months or less as of the date of acquisition to be cash equivalents.

Investments

The Company considers investments with an original maturity greater than three months and remaining maturities less than 12 months to be short-term investments. The Company classifies those investments that are not required for use in current operations and that mature in more than 12 months as long-term investments.

The Company classifies its marketable debt securities as available for sale and reports them at fair value, with unrealized gains and losses recorded in accumulated other comprehensive income (loss). For investments sold prior to maturity, the cost of investments sold is based on the specific identification method. Realized gains and losses on the sale of investments are recorded in other income (expense), net in the consolidated statement of operations.

If the estimated fair value of a marketable debt security is below its amortized cost basis, the Company evaluates whether it is more likely than not that the Company will be required to sell the security before its anticipated recovery in market value and whether credit losses exist for the related securities. Credit-related losses are recognized as an allowance for credit losses on the balance sheet with a corresponding adjustment to earnings. Unrealized gains and losses that are unrelated to credit deterioration are reported in accumulated other comprehensive income (loss).

Fair Value of Financial Instruments

Fair value is defined as the price that would be received for sale of an asset or paid for transfer of a liability, in an orderly transaction between market participants at the measurement date. U.S. GAAP establishes a three-tier fair value hierarchy, which prioritizes the inputs used in measuring fair value.

The hierarchy gives the highest priority to unadjusted quoted prices in active markets for identical assets or liabilities (Level 1 measurements) and the lowest priority to unobservable inputs (Level 3 measurements). These tiers include:

Level 1, defined as observable inputs such as quoted prices for identical instruments in active markets;

Level 2, defined as inputs other than quoted prices in active markets that are either directly or indirectly observable such as quoted prices for similar instruments in active markets or quoted prices for identical or similar instruments in markets that are not active; and

Level 3, defined as unobservable inputs in which little or no market data exists, therefore requiring an entity to develop its own assumptions, such as valuations derived from valuation techniques in which one or more significant inputs or significant value drivers are unobservable.

Nautilus Biotechnology, Inc.Notes to Consolidated Financial Statements—(Continued)

In some circumstances, the inputs used to measure fair value might be categorized within different levels of the fair value hierarchy. In those instances, the fair value measurement is categorized in its entirety in the fair value hierarchy based on the lowest level input that is significant to the fair value measurement.

The carrying amounts of cash and cash equivalents, prepaid expenses and other current assets, accounts payable and accrued expenses and other liabilities approximate their respective fair values due to their short-term nature.

Inventory, net

Inventory is stated at the lower of cost or net realizable value. As of December 31, 2025, inventory balances were immaterial and primarily related to early manufacturing activities in advance of our Early Access Program.

Property and Equipment, net

Property and equipment, net, consisting primarily of laboratory equipment, computers, furniture and fixtures, and office equipment are recorded at cost. The Company utilizes the straight-line method of depreciation over the estimated useful lives of the assets:

When assets are retired or otherwise disposed of, the cost and related accumulated depreciation are removed from the accounts, and any resulting gain or loss is recognized as income or loss for the period.

Maintenance and repairs are charged to operating expense in the period incurred.

Impairment of Long-Lived Assets

The Company periodically reviews its long-lived assets, including property and equipment, for impairment whenever events or changes in circumstances indicate that the carrying amount of the asset may not be recoverable.

With respect to property and equipment, the Company compares the carrying value of the long-lived assets with the estimated future net undiscounted cash flows expected to result from the use and eventual disposition of the asset (or asset group). Should the sum of the estimated future net undiscounted cash flows be less than the carrying value, the Company would recognize an impairment loss as of that date. An impairment loss would be measured by comparing the amount by which the carrying value exceeds the fair value of the long-lived assets. No impairment of long-lived assets was recorded in any of the periods presented.

Leases

The Company determines if an arrangement includes a lease at inception by assessing whether there is an identified asset and whether the contract conveys the right to control the use of the identified asset for a period of time in exchange for consideration. Operating leases with a term of more than one year are included in operating lease right-of-use (“ROU”) assets and operating lease liabilities on the Company's consolidated balance sheets. ROU assets represent the Company's right to use an underlying asset for the lease term and lease liabilities represent the obligation to make lease payments. Operating lease ROU assets and liabilities are recognized on the lease commencement date based on the present value of the future minimum lease payments over the lease term. The Company uses the incremental borrowing rate commensurate with the lease term based on the information available at the lease commencement date in determining the present value of the lease payments as the Company's leases generally do not provide an implicit rate. ROU assets initially equal the lease liability, adjusted for any prepaid lease payments and initial direct costs incurred, less any lease incentives received. Certain of the Company's leases

Nautilus Biotechnology, Inc.Notes to Consolidated Financial Statements—(Continued)

include renewal options which allow the Company to, at its election, renew or extend the lease for a fixed or indefinite period of time. These renewal periods are included in the lease terms when the Company is reasonably certain the options will be exercised. Lease expense is recognized on a straight-line basis over the lease term when leases are operating leases. If it is considered a finance lease, expense is recognized over the lease term within interest expense and amortization in the Company’s consolidated statements of operations. The Company also has lease arrangements with lease and non-lease components. The Company elected the practical expedient not to separate non-lease components from lease components for the Company's facility leases and to account for the lease and non-lease components as a single lease component. The Company also elected to apply the short-term lease measurement and recognition exemption in which ROU assets and lease liabilities are not recognized for leases with terms of 12 months or less.

Income Taxes

The Company accounts for income taxes using the asset and liability method. Deferred tax assets and liabilities are recognized for the future tax consequences attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax bases and operating loss and tax credit carryforwards. Deferred tax assets and liabilities are measured using enacted tax rates expected to apply to taxable income in the years in which those temporary differences are expected to be recovered or settled. The effect on deferred tax assets and liabilities of a change in tax rates is recognized in income in the period that includes the enactment date. Valuation allowances are provided if, based upon the weight of available evidence, it is more likely than not that some or all of the net deferred tax assets will not be realized. In making such a determination, the Company considers all available positive and negative evidence, including future reversals of existing taxable temporary differences, projected future taxable income, tax-planning strategies, and recent results of operations, primarily over the most recent three-year period.

The Company recognizes the effect of income tax positions only if those positions are more likely than not of being sustained upon an audit. Recognized income tax positions are measured at the largest amount that is greater than 50% likely of being recognized. Changes in recognition or measurement are reflected in the period in which the change in judgement occurs.

Research and Development

Costs for research and development activities are expensed in the period in which they are incurred. Research and development expenses consist of costs incurred in performing research and development activities, including salaries, related benefits and stock-based compensation expense for product development personnel, laboratory supplies and equipment, depreciation and amortization, external costs of vendors engaged to conduct research and development activities, acquired in-process research and development, and allocated expenses for technology and facilities.

As part of the process of preparing its financial statements, the Company estimates its accrued expenses. This process involves reviewing quotations and contracts, identifying services that have been performed on the Company’s behalf and estimating the level of services performed and the associated cost incurred for services for which the Company has not yet been invoiced or otherwise notified of the actual cost. The majority of the Company’s service providers invoice monthly in arrears for services performed or when contractual milestones are met. The Company makes estimates of its accrued expenses at the end of each reporting period based on the facts and circumstances known to the Company at that time. The significant estimates in the Company’s accrued research and development expenses relate to expenses incurred with respect to academic research centers and other vendors in connection with research and development activities for which the Company has not yet been invoiced.

Stock-based Compensation

The Company accounts for stock-based compensation expense by calculating the estimated fair value of each employee and non-employee award at the grant date or modification date by applying the Black-Scholes option pricing model (the “model”). The model utilizes the NASDAQ closing price of the Company’s common stock at the measurement date, the expected or contractual term of the option, the expected stock price volatility, risk-free interest rates, and expected dividend yield of the common stock. Stock-based compensation expense is recognized

Nautilus Biotechnology, Inc.Notes to Consolidated Financial Statements—(Continued)

on a straight-line basis over the requisite service period, which is generally the vesting period. Forfeitures are recognized in the period in which the forfeiture occurs. The Company classifies stock-based compensation expense in its statement of operations in the same manner in which the award recipient’s payroll costs are classified or in which the award’s recipient’s service payments are classified. The Company’s stock-based compensation programs include stock options grants, as well as shares issued under its 2021 Employee Stock Purchase Plan.

The Company calculates the expected term as the mid-point between the requisite service period and the contractual term of the award.

The Company bases its estimate of expected volatility on the historical volatility of comparable public companies from a representative peer group selected based on industry, financial, and market capitalization data.

The Company has never declared or paid any dividends and does not currently expect to do so in the future. The risk-free interest rate used in the model is based on the implied yield currently available in the U.S. Treasury securities at maturity with an equivalent term.

Comprehensive Loss

Comprehensive loss consists of net loss and other gains or losses affecting stockholders’ equity that, under U.S. GAAP are excluded from net loss. For the years ended December 31, 2025 and 2024, unrealized gains and losses on marketable debt securities were included as a component of comprehensive loss.

Net Loss per Share Attributable to Common Stockholders

Basic net loss per common share is calculated by dividing the net loss attributable to common stockholders by the weighted-average number of common stock outstanding during the period, without consideration of potentially dilutive securities. Diluted net loss per share is computed by dividing the net loss attributable to common stockholders by the weighted-average number of common stock and potentially dilutive securities outstanding for the period. For the purposes of the diluted net loss per share calculation, stock options and shares to be purchased from the Employee Stock Purchase Plan are considered to be potentially dilutive securities. The net loss is attributed entirely to the Company’s common stockholders. Since the Company has reported a net loss for all periods presented, diluted net loss per common share is the same as basic net loss per common share for those periods.

Accounting Pronouncements

Recently Adopted Accounting Standards

In December 2023, the FASB issued ASU 2023-09, “Income Taxes (Topic 740): Improvements to Income Tax Disclosures,” to enhance the transparency and decision usefulness of income tax disclosures. The ASU is effective for the Company for the fiscal year ending December 31, 2025. The Company adopted the ASU prospectively during the fiscal year ended December 31, 2025 and the related disclosure requirements are noted in Note 6, “Income Taxes.”

Recently Issued Accounting Pronouncements

In November 2024, the FASB issued ASU 2024-03, Income Statement—Reporting Comprehensive Income—Expense Disaggregation Disclosures (Subtopic 220-40). The amendments in this update require disclosure, in the notes to financial statements, of specified information about certain costs and expenses. The ASU is effective for the Company for the fiscal year ending December 31, 2027 and for interim periods beginning after December 31, 2027. The Company does not anticipate adoption to have a material impact on its consolidated financial statements and related disclosures.

Nautilus Biotechnology, Inc.Notes to Consolidated Financial Statements—(Continued)

3. Fair Value Measurements

The following table details the assets carried at fair value and measured on a recurring basis within the three levels of fair value as of December 31, 2025 and 2024:

Short-term investments have a contractual maturity date that is one year or less from the respective balance sheet date. Long-term investments have a contractual maturity date that is more than one year, but less than two years from the respective balance sheet date.

Nautilus Biotechnology, Inc.Notes to Consolidated Financial Statements—(Continued)

The unrealized losses and fair values of available-for-sale securities that have been in an unrealized loss position for a period of less than and greater than 12 months as of December 31, 2025 are as follows:

The Company reviewed its investment portfolio based on the underlying risk profile of the securities and have no loss expectation for these investments. The Company reviewed the securities in an unrealized loss position and evaluated the current expected credit loss by considering factors such as historical experience, market data, issuer-specific factors, and current economic conditions. The Company recognizedno credit losses during the years ended December 31, 2025 and 2024, and hadno allowance for credit losses as of December 31, 2025 and 2024.

4. Composition of Certain Consolidated Financial Statement Line Items

Property and Equipment, Net

Property and equipment consisted of the following:

The Company recorded $1.7 million and $2.0 million of depreciation expense for the years ended December 31, 2025 and 2024, respectively, which was primarily allocated to research and development expense.

Accrued Expenses and Other Liabilities

Accrued expenses and other liabilities consisted of the following:

Nautilus Biotechnology, Inc.Notes to Consolidated Financial Statements—(Continued)

Cash, Cash Equivalents and Restricted Cash

Cash, cash equivalents and restricted cash consisted of the following:

Other long-term assets consisted of $1.0 million of restricted cash and $0.2 million of deposits as of December 31, 2025 and 2024.

5. Common Stock

There were 126,469,610 shares issued and outstanding as of December 31, 2025.

Common Stock Reserved for Future Issuance

Shares of common stock reserved for future issuance on an as-if converted basis, were as follows:

6. Income Taxes

The Company is liable for income taxes in the United States. For the years ended December 31, 2025 and 2024, the Company did not have any income for income tax purposes and therefore, no tax liability or expense has been recorded in these financial statements. The difference between the tax at the statutory federal tax rate andno tax provision recorded by the Company is primarily due to the Company’s full valuation allowance against its deferred tax assets.

The following table presents the required disclosures prior to our adoption of ASU 2023-09 and reconciles the U.S. federal statutory income tax amount to the effective income tax amount for the year ended December 31, 2024:

Nautilus Biotechnology, Inc.Notes to Consolidated Financial Statements—(Continued)

The Company adopted ASU 2023-09 "Income Taxes (Topic 740): Improvements To Income Tax Disclosures" on a prospective basis beginning with the year ended December 31, 2025. The following table presents required disclosure pursuant to ASU 2023-09 and reconciles the U.S. federal statutory tax amount and rate to our effective amount and rate for the year ended December 31, 2025:

The "One Big Beautiful Bill Act" (OBBBA) enacted on July 4, 2025, introduced notable changes to the U.S. Internal Revenue Code, including immediate expensing of domestic Section 174 costs. Section 174 costs are expenditures which represent research and development costs that are incident to the development or improvement of a product, process, formula, invention, computer software, or technique. As previously required under the Tax Cuts and Jobs Act, the Company capitalized research and development expenditures in the years ended December 31, 2022 through December 31, 2024. With the enactment of OBBBA, the Company began deducting domestic Section 174 costs in 2025.

As of December 31, 2025, the Company had federal net operating loss carryforwards of $0.5 million that begin to expire in 2037 and federal net operating loss carryforwards of $203.2 million that arose after the 2017 tax year that will carryforward indefinitely and will be subject to the 80% of taxable income limitation. The Company has state net operating loss carryforwards of $197.9 million that will begin to expire in 2037.

As of December 31, 2025, the Company had research and development tax credit carryover of $9.6 million and $6.5 million for federal and state tax purposes, respectively. If not utilized, the federal carryforward will expire in various amounts beginning in 2039. The California credits can be carried forward indefinitely.

The Company has evaluated the positive and negative evidence bearing upon its ability to realize the deferred tax assets. Management has considered the Company’s history of cumulative net losses incurred since inception and its lack of revenue since inception and has concluded that it is more likely than not that the Company will not realize the benefits of the deferred tax assets. Accordingly, the Company has provided a full valuation allowance against the net deferred tax assets. The valuation allowance increased by $15.0 million during the year ended December 31, 2025. Management reevaluates the positive and negative evidence at each reporting period.

Nautilus Biotechnology, Inc.Notes to Consolidated Financial Statements—(Continued)

Deferred income taxes reflect the net tax effects of loss and credit carryforwards and temporary differences between the carrying amounts of assets and liabilities for financial reporting purposes and the amounts used for income tax purposes. Components of the Company’s deferred tax assets are as follows:

The Company began to file income tax returns in the United States in 2017. All tax years are open to examination.

A valuation allowance of $93.4 million and $78.4 million at December 31, 2025 and 2024, respectively, has been recognized to offset net deferred tax assets where realization of such net deferred tax assets is determined to be more likely than not to not be realized. The valuation allowance increased by $15.0 million in 2025 and increased by $20.2 million in 2024, which was primarily due to changes in our deferred tax asset balances. The increases in the valuation allowance in 2025 and 2024 was primarily due to the net operating loss and tax credit generation, capitalized research and development expense and stock-based compensation expense.

As required under ASU 2023-09, the Company has included only the portion of the valuation allowance related to federal deferred tax assets in the "change in valuation allowance" line of the rate reconciliation. The following table presents a reconciliation of the total change in the valuation allowance (in thousands):

The Company had an unrecognized tax benefit balance of $3.2 million and $3.1 million related to research and development credits and California net operating loss carryforward as of December 31, 2025 and 2024, respectively. No amount of unrecognized tax benefits as of December 31, 2025, if recognized, would reduce the Company’s effective tax rate because the benefits would be in the form of tax credit carryforwards, which would be reduced to $0 by a full valuation allowance. Because the statute of limitations does not expire until after the net operating loss

Nautilus Biotechnology, Inc.Notes to Consolidated Financial Statements—(Continued)

and credit carryforwards are actually used, the statutes are still open on calendars years ending 2017 forward for federal and state purposes.

A reconciliation of the beginning and ending amount of the liability for uncertain tax positions, excluding potential interest and penalties, is as follows:

Net operating loss and tax credit carry-forwards are subject to review and possible adjustment by the Internal Revenue Service (the “IRS”) and may become subject to an annual limitation in the event of certain cumulative changes in the ownership interest of significant stockholders over a three-year period in excess of 50% as defined under Sections 382 and 383 in the Code, which could limit the amount of tax attributes that can be utilized annually to offset future taxable income or tax liabilities. The amount of the annual limitation is determined based on the Company’s value immediately prior to the ownership change. Subsequent ownership changes may further affect the limitation in future years. The Company has not, as yet, conducted a study to determine if any such changes have occurred that could limit its ability to use the net operating loss and tax credit carryforwards.

7. Equity Incentive Plans and Stock-based Compensation

On June 8, 2021, the stockholders of the Company approved the 2021 Equity Incentive Plan (“2021 Plan”) and the 2021 Employee Stock Purchase Plan (“2021 ESPP”). As of December 31, 2025,29,341,567 and 5,518,072 shares were available for grant under the 2021 Plan and 2021 ESPP, respectively.

2021 Employee Stock Purchase Plan

Under the 2021 ESPP, participants are permitted to purchase shares of Common Stock, up to the IRS allowable limit, through contributions (in the form of payroll deductions or otherwise to the extent permitted by the administrator of the 2021 ESPP) of up to 15% of their eligible compensation. Participants are permitted to purchase shares of the Company’s Common Stock at 85% of the lower of the fair market value of the Company’s Common Stock on the first trading day of an offering period or on the last trading date in each purchase period. The Company offers asix-month purchase period. Participants may end their participation at any time during an offering and will be paid their accrued contributions that have not yet been used to purchase shares. Participation ends automatically upon termination of employment with the Company. The number of shares of common stock available for issuance under the 2021 ESPP will be increased on the first day of each fiscal year, in an amount equal to the least of (i)3,734,500 shares of common stock, (ii) a number of shares of common stock equal to one percent (1%) of the total number of shares of all classes of common stock of the Company on the last day of the immediately preceding fiscal year, or (iii) such number of shares determined by the Administrator no later than the last day of the immediately preceding fiscal year.

2021 Equity Incentive Plan

Under the 2021 Plan, the Company can grant incentive stock options, nonstatutory stock options, stock appreciation rights, restricted stock, restricted stock units and performance awards to employees, non-employee directors and consultants. Options generally expireten years after the date of grant. The number of shares available for issuance under the 2021 Plan will be increased on the first day of each fiscal year, in an amount equal to the least of (i)18,672,200 shares, (ii) a number of shares equal to five percent (5%) of the total number of shares of all classes of common stock of the Company outstanding on the last day of the immediately preceding fiscal year, or (iii) such number of shares determined by the Administrator no later than the last day of the immediately preceding fiscal year.

Nautilus Biotechnology, Inc.Notes to Consolidated Financial Statements—(Continued)

2017 Equity Incentive Plan

At the time of adoption of the 2021 Plan and the 2021 ESPP, no further awards will be granted under the 2017 Equity Incentive Plan (“2017 Plan”). Stock-based awards forfeited or cancelled from the 2017 Plan are returned to the pool of shares of Common Stock available for issuance under the 2021 Plan.

Grant Date Fair Value of Stock Options

In determining the compensation cost of the option awards, the fair value for each option award has been estimated using the Black Scholes model. The significant assumptions used in these calculations are summarized as follows:

Expected term: The expected term of stock options represents the weighted-average period the stock options are expected to remain outstanding. The Company does not have sufficient historical exercise and post-vesting termination activity to provide accurate data for estimating the expected term of options and has opted to use the “simplified method,” whereby the expected term equals the arithmetic average of the vesting term and the original contractual term of the option.

Expected volatility: Historically, the Company has been a private company and lacked company‑specific historical and implied volatility information for its common stock. Therefore, the expected volatility of the Company’s common stock was determined by using an average of historical volatilities of selected industry peers deemed to be comparable to the Company’s business corresponding to the expected term of the awards and the Company expects to continue to do so until such time as the Company has adequate historical data regarding the volatility of its traded common stock price.

Expected dividend yield: The expected dividend rate iszero as the Company has no history or expectation of declaring dividends on its common stock.

Risk-free interest rate: The risk-free interest rate is based on the U.S. Treasury yield curve in effect at the time of grant for zero-coupon U.S. Treasury notes with maturities corresponding to the expected term of the awards.

The following table summarizes option award activity during the year ended December 31, 2025:

As of December 31, 2025, there was $7.7 million of total unrecognized compensation expense expected to be recognized over a weighted average-period of 2.2 years. The total intrinsic value of options exercised during the

Nautilus Biotechnology, Inc.Notes to Consolidated Financial Statements—(Continued)

years ended December 31, 2025 and 2024 was $0.1 million and $1.3 million, respectively. Aggregate intrinsic value represents the difference between the fair market value of the common stock and the exercise price of outstanding, in-the-money options.

The weighted-average grant-date fair value of options granted during the years ended December 31, 2025 and 2024 was $0.82 and $2.16 per share, respectively.

Stock-based Compensation Expense

The following sets forth the total stock-based compensation expense for the Company’s stock options and ESPP included in the Company’s consolidated statements of operations:

8. Commitments and Contingencies

Purchase Commitments

Open purchase commitments are for the purchase of goods and services related to, but not limited to, research and development, facilities, and professional services under non-cancellable contracts. They were not recorded as liabilities on the consolidated balance sheet as of December 31, 2025 as the Company had not yet received the related goods or services. As of December 31, 2025, the Company had open purchase commitments for goods and services of $1.5 million, of which $1.4 million are expected to be received through the next 12 months.

Legal Proceedings

From time to time, the Company may become involved in litigation relating to claims arising from the ordinary course of business. The Company may record accruals for loss contingencies associated with legal matters when it is probable that a liability will be incurred, and the amount of the loss can be reasonably estimated. Amounts accrued for legal contingencies often result from a complex series of judgments about future events and uncertainties that rely heavily on estimates and assumptions. The ability to make such estimates and judgments can be affected by various factors including, among other things, whether damages sought in the proceedings are unsubstantiated or indeterminate; scientific and legal discovery has not commenced or is not complete; proceedings are in early stages; matters present legal uncertainties; there are significant facts in dispute; procedural or jurisdictional issues. Loss contingency accruals would be included in accrued and other liabilities and general and administrative expenses.

U.S. District Court Proceedings

On December 14, 2023, we filed suit in the United States District Court for the Northern District of California (the “Court”) against Somalogic, Inc. (Somalogic) which recently merged with and is now part of “Standard Biotools, Inc.,” and the California Institute of Technology. This suit sought declaratory judgment that Nautilus does not infringe any claims of US Patent No. 7,842,793 related to DNA origami structures (the ‘793 Patent), which Somalogic had allegedly licensed from the California Institute of Technology through its purchase of Palamedrix, Inc. On November 19, 2024, the Company, Standard Biotools, Inc., and the California Institute of Technology agreed to dismiss the suit and settle any and all disputes and/or claims related to the suit.

Leases

The Company is obligated under certain non-cancellable operating leases for office space and laboratory space. This space includes operating leases in Seattle, Washington, San Carlos, California, and San Diego, California.

Nautilus Biotechnology, Inc.Notes to Consolidated Financial Statements—(Continued)

Seattle Lease

In July 2021, the Company entered into a 7-year non-cancellable operating lease, which commenced in August 2021, for office space in Seattle, Washington. Total non-cancellable payments under this lease aggregate $4.5 million through June 2028.

San Carlos Leases

In December 2020, the Company entered into a new lease in San Carlos, California forten years which commenced in October 2021 and expiring in October 2031 with total minimum lease payments of $40.7 million.

In December 2021, the Company entered into another lease in San Carlos, California fornine years commencing in March 2023. The lease provided the Company the option to terminate the agreement without significant penalty after five years from the commencement date. At lease commencement, the Company concluded it was reasonably certain to exercise the early termination option and determined that the lease term wasfive years with total minimum lease payments of $7.2 million. The Company utilized $2.0 million from the landlord with an interest rate of 7% to finance its tenant improvements. The principal and interest payments are included in the payments used to measure the lease liability.

In December 2025, the Company revised expectations regarding future space requirements and concluded it was no longer reasonably certain the Company will exercise the early termination option. Based on this determination, the Company remeasured the lease to reflect an updated remaining lease term through October 2031, resulting in an increase to the lease liability and corresponding operating lease right-of-use (“ROU”) asset of approximately $4.2 million as of the remeasurement date. The revised measurement reflects the present value of the remaining fixed lease payments discounted using the Company’s updated incremental borrowing rate. No other significant assumptions were modified as part of the remeasurement.

San Diego Lease

In November 2022, the Company entered into a lease in San Diego, California for 39 months commencing in December 2022. Total non-cancellable payments under this lease aggregate $2.1 million through March 2026.

The components of lease costs which were included in operating expenses in the consolidated statements of operations were as follows:

For the years ended December 31, 2025 and 2024, cash paid for amounts included in the measurement of operating lease liabilities included in cash flows used in operating activities was $7.2 million and $7.0 million, respectively.

As of December 31, 2025, the weighted-average remaining lease term and weighted-average discount rate for operating leases was 5.6 years and 9.0%, respectively.

Nautilus Biotechnology, Inc.Notes to Consolidated Financial Statements—(Continued)

The following table summarizes the Company's future principal contractual obligations for operating lease commitments as of December 31, 2025:

The Company has $1.0 million in cash-collateralized letters of credit withone financial institution in lieu of security deposits in connection with the San Carlos and San Diego lease agreement.

Indemnification Agreements

In the ordinary course of business, the Company enters into agreements that may include indemnification provisions. Pursuant to such agreements, the Company may indemnify, hold harmless and defend an indemnified party for losses suffered or incurred by the indemnified party. Some of the provisions will limit losses to those arising from third-party actions. In some cases, the indemnifications will continue after the termination of the agreement. The maximum potential amount of future payments the Company could be required to make under these provisions is not determinable. The Company has never incurred material costs to defend lawsuits or settle claims related to these indemnification provisions.

The Company has also agreed to indemnify its directors and executive officers for costs associated with any fees, expenses, judgments, fines and settlement amounts incurred by them in any action or proceeding to which any of them are, or are threatened to be, made a party by reason of their service as a director or officer. The Company maintains director and officer insurance coverage that would generally enable it to recover a portion of any future amounts paid. The Company may be subject to indemnification obligation by law with respect to the actions of its employees under certain circumstances and in certain jurisdictions.

9. Basic and Diluted Net Loss per Share

The following tables set forth the computation of the Company’s basic and diluted net loss per share attributable to common stockholders for the years ended December 31, 2025 and 2024:

Nautilus Biotechnology, Inc.Notes to Consolidated Financial Statements—(Continued)

The potential shares of common stock that were excluded from the computation of diluted net loss per share attributable to common stockholders for the periods presented because including them would have had an antidilutive effect were as follows:

10. Segment Information

The Company’s Chief Executive Officer is its CODM. The Company’s CODM uses consolidated net loss in assessing operating decisions, allocating resources and evaluating financial performance. Consolidated net loss is used to monitor budget versus actual results. The Company identified the following significant segment expenses for its single reportable segment: