Annexon Inc

1. Organization

Annexon, Inc., or the Company, is a clinical-stage biopharmaceutical company pioneering a new class of complement medicines for people living with devasting inflammatory-related diseases. The Company is located in Brisbane, California and was incorporated in Delaware in March 2011.

The Company’s wholly-owned subsidiary, Annexon Biosciences Australia Pty Ltd, or the Subsidiary, is a proprietary limited company incorporated in 2016 and domiciled in Australia.

Liquidity

Since inception, the Company has been involved primarily in performing research and development activities, conducting clinical trials, hiring personnel, and raising capital to support and expand these activities. The Company has experienced losses and negative cash flows from operations since its inception and, as of December 31, 2023, had an accumulated deficit of$572.5 million and cash and cash equivalents and short-term investments of$259.7 million.

The Company has historically funded its operations through the issuance of shares of its common stock and warrants. Based on projected activities, management projects that existing cash and cash equivalents and short-term investments will enable the Company to fund its operating expenses and capital expenditure requirements for at least twelve months from the date of issuance of these financial statements. The Company’s future viability beyond that point is dependent on its ability to achieve development milestones and obtain additional funding. Management expects to continue to incur losses and negative cash flows from operations for at least the next several years. There are uncertainties associated with the Company’s ability to (1) obtain additional equity or debt financing on terms that are favorable to the Company, (2) enter into collaborative agreements with strategic partners, and (3) succeed in its future operations. If the Company is not able to obtain the required funding for its operations or is not able to obtain funding on terms that are favorable to the Company, it could be forced to delay, reduce or eliminate its research and development programs and its business could be materially harmed.

Basis of Presentation and Significant Accounting Policies

Use of Estimates

The preparation of financial statements in conformity with accounting principles generally accepted in the United States of America, or GAAP, requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported expenses during the reporting period. Management evaluates its estimates, including but not limited to the fair value of investments, operating lease right-of-use assets and liabilities, valuation of deferred tax assets and uncertain tax positions (including valuation allowance), clinical trial accruals and stock-based compensation. The Company evaluates its estimates and assumptions on an ongoing basis using historical experience and other factors and adjusts those estimates and assumptions when facts and circumstances dictate. Actual results could differ from those estimates.

Principles of Consolidation

The consolidated financial statements include the operations of Annexon, Inc. and its wholly owned subsidiary and include the results of operations and cash flows of these entities. All intercompany balances and transactions have been eliminated in consolidation.

Segments

The Company’s chief operating decision maker is its Chief Executive Officer. The Chief Executive Officer reviews financial information on an aggregate basis for the purposes of evaluating financial performance and allocating the Company’s resources. Accordingly, the Company has determined that it operates inone segment.

Cash, Cash Equivalents and Restricted Cash

The Company considers all highly liquid instruments with an original maturity of three months or less at time of purchase to be cash equivalents. Cash equivalents, which includes amounts invested in money market funds and short-term government bonds, are stated at fair value.

Restricted cash as of December 31, 2023 relates to the letters of credit established for the Company’s office lease.

The following table provides a reconciliation of cash, cash equivalents, and restricted cash reported within the consolidated balance sheets that sum to the total of the same amounts shown in the consolidated statements of cash flows (in thousands):

Short-Term Investments

Short-term investments have been classified as available-for-sale and are carried at estimated fair value as determined based upon quoted market prices or pricing models for similar securities. The Company determines the appropriate classification of its investments in debt securities at the time of purchase. Available-for-sale securities with original maturities beyond three months at the date of purchase are classified as current based on their availability for use in current operations.

The Company evaluates, on a quarterly basis, its available-for-sale debt securities for potential impairment. For available-for-sale debt securities in an unrealized loss position, the Company assesses whether such declines are due to credit loss based on factors such as changes to the rating of the security by a ratings agency, market conditions and supportable forecasts of economic and market conditions, among others. If credit loss exists, the Company assesses whether it has plans to sell the security or it is more likely than not it will be required to sell any available-for-sale debt security before recovery of its amortized cost basis. If either condition is met, the security’s amortized cost basis is written down to fair value and is recognized through interest and other income (expense), net. If neither condition is met, declines as a result of credit losses, if any, are recognized as an allowance for credit loss, limited to the amount of unrealized loss, through interest and other income (expense), net. Any portion of the unrealized loss that is not a result of a credit loss, is recognized in other comprehensive income (loss). Realized gains and losses, if any, on available-for-sale debt securities are included in interest and other income (expense), net.

The cost of investments sold is based on the specific-identification method. Interest onavailable-for-sale debt securities is included in interest and other income (expense), net.

Property and Equipment, Net

Property and equipment are carried at cost less accumulated depreciation. Depreciation is computed using the straight-line method over the estimated useful lives of the respective assets. Depreciation begins at the time the asset is placed in service. Maintenance and repairs are charged to operations as incurred. Upon sale or retirement of assets, the cost and related accumulated depreciation are removed from the balance sheet and the resulting gain or loss is reflected in operations in the period realized.

The useful lives of the property and equipment are as follows:

Impairment of Long-Lived Assets

The Company evaluates its long-lived assets, including property and equipment, for impairment whenever events or changes in circumstances indicate that the carrying amount of these assets may not be recoverable. Recoverability of these assets is measured by comparison of the carrying amount of each asset to the future undiscounted cash flows the asset is expected to generate over its remaining life. When indications of impairment are present and the estimated undiscounted future cash flows from the use of these assets is less than the assets’ carrying value, the related assets will be written down to fair value. There wereno impairments of the Company’s long-lived assets for the periods presented.

Leases

The Company determines if an arrangement is a lease at inception. The Company includes operating leases in operating lease right of use, or ROU, assets, current and noncurrent operating lease liabilities in the Company’s consolidated balance sheets. The ROU assets represent the Company’s right to use an underlying asset for the lease term and lease liabilities represent the Company’s obligation to make lease payments arising from the lease. Operating lease liabilities are recognized at the commencement date based on the present value of lease payments over the lease term. The Company measures the ROU assets based on the associated lease liabilities adjusted for any lease incentives such as tenant improvement allowances. As most of the leases do not provide an implicit rate, the Company generally uses its incremental borrowing rate based on the estimated rate of interest for collateralized borrowing over a similar term of the lease payments at the commencement date. The Company’s lease terms may include options to extend or terminate the lease when it is reasonably certain that the Company will exercise the option. Lease expense for lease payments is recognized on a straight-line basis, net of sublease income, over the lease term.

As a practical expedient, the Company elected, for all facility leases, not to separate non-lease components from lease components and instead to account for each separate lease component and its associated non-lease components as a single lease component. The Company elected to exclude from its balance sheets recognition of leases having a term of 12 months or less (short-term leases).

Income Taxes

Income taxes are accounted for under 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 carry forwards. 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 established when necessary to reduce deferred taxes to the amounts expected to be realized.

The Company recognizes benefits of uncertain tax positions if it is more likely than not that such positions will be sustained upon examination based solely on their technical merit, as the largest amount of benefit that is more likely than not to be realized upon the ultimate settlement. The Company’s policy is to recognize interest and penalties related to the underpayment of income taxes as a component of income tax expense or benefit. To date, there have been no interest or penalties charged in relation to the unrecognized tax benefits.

Commitments and Contingencies

Liabilities for loss contingencies arising from claims, assessments, litigation, fines, and penalties and other sources are recorded when it is probable that a liability has been incurred and the amount can be reasonably estimated. Legal costs incurred in connection with loss contingencies are expensed as incurred.

Warrants

Warrants are accounted for as either derivative liabilities or as equity instruments depending on the specific terms of the agreement. The Company’s pre-funded and common warrants are equity-classified instruments that were recorded in additional paid-in capital at issuance and are not subject to remeasurement. The Company periodically evaluates changes in facts and circumstances that could impact the classification of warrants. As of December 31, 2023, there were pre-funded warrants to purchase up to 40,492,923 shares of common stock and common warrants to purchase up to 8,427,508 shares of common stock outstanding.

Research and Development Expense

Research and development expenses consist primarily of direct and indirect costs incurred for the development of the Company’s product candidates.

Direct expenses include (i) preclinical and clinical outside service costs associated with discovery, preclinical and clinical testing of the Company’s product candidates; (ii) professional services agreements with third-party contract organizations, investigative clinical trial sites and consultants that conduct research and development activities on the Company’s behalf; (iii) contract manufacturing costs to produce clinical trial materialsand commercial materials to support future biologics license applications (BLA) to the FDA, and (iv) laboratory supplies and materials. Indirect expenses include (A) compensation and personnel-related expenses (including stock-based compensation), (B) allocated expenses for facilities and depreciation; and (C) other indirect costs.

Research and development costs are expensed as incurred. Payments made to third parties are under agreements that are generally cancelable by the Company. Advance payments for research and development activities are deferred as prepaid expenses. The prepaid amounts are expensed as the related services are performed.

The Company estimates preclinical studies and clinical trial expenses based on the services performed pursuant to contracts with research institutions and clinical research organizations that conduct and manage preclinical studies and clinical trials on the Company’s behalf. The Company also estimates manufacturing costs based on services performed pursuant to contracts with contract manufacturing organizations that develop and manufacture product on the Company’s behalf. In accruing service fees, the Company estimates the period over which services will be performed and the level of effort to be expended in each period. These estimates are based on the Company’s communications with the third-party service providers and on information available at each balance sheet date. If the actual timing of the performance of services or the level of effort varies significantly from the estimate, the Company will adjust the accrual accordingly to reflect the best information available at the time of the financial statement issuance. The Company has not experienced any material differences between accrued costs and actual costs incurred since its inception.

Stock-Based Compensation

The Company accounts for stock-based compensation arrangements with employees and non-employee directors and consultants using a fair value method which requires the recognition of compensation expense for costs related to all stock-based payments, including stock options and restricted stock units, or RSUs. The fair value method requires the Company to estimate the fair value of stock options to employees and non-employees on the date of grant using the Black-Scholes option pricing model. The fair value of RSU awards is based on the fair value of the underlying common stock as of the grant date.

Stock-based compensation costs are based on the fair value of the underlying option calculated using the Black-Scholes option pricing model and recognized as expense on a straight-line basis (for all but performance-based awards for which the accelerated method is used) over the requisite service period, which is the vesting period.

Determining the appropriate fair value model and related assumptions requires judgment, including estimating expected term, expected stock price volatility, risk-free interest rate and dividend yield. The Company accounts for forfeitures as they occur.

Net Loss Per Share

Basic net loss per share attributable to common stockholders is calculated by dividing the net loss by the weighted-average number of shares of common stock outstanding for the period, without consideration for potential dilutive shares of common stock. As the Company was in a loss position for all periods presented, basic net loss per share is the same as diluted net loss per share because the effects of potentially dilutive securities are antidilutive.

Concentration of Credit Risk

Financial instruments that potentially subject the Company to concentrations of credit risk consist primarily of cash and cash equivalents and short-term investments. The Company’s cash andcash equivalents and short-term investments are held by high credit quality financial institutions in the United States. At times, such deposits may be in excess of the Federal Depository Insurance Corporation insured limits. Management believes that the financial institutions are financially sound, and accordingly, minimal credit risk exists with respect to the financial institutions.

Recently Issued Accounting Pronouncements

In November 2023, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update (ASU) 2023-07, Segment Reporting: Improvements to Reportable Segment Disclosures, which requires disclosure of incremental segment information on an interim and annual basis. This ASU is effective for fiscal years beginning after December 15, 2023, and interim periods within fiscal periods beginning after December 15, 2024, and requires retrospective application to all prior periods presented in the financial statements. The Company is currently evaluating the impact of the guidance on the consolidated financial statements and disclosures.

In December 2023, the FASB issued ASU 2023-09, Income Taxes: Improvements to Income Tax Disclosures, which requires enhanced annual disclosures regarding the rate reconciliation and income taxes paid information. ASU 2023-09 is effective for fiscal years beginning after December 15, 2024 and may be adopted on a prospective or retrospective basis. Early adoption is permitted. The Company is evaluating the impact of this guidance on its consolidated financial statements and related disclosures.

Fair Value Measurements

The Company utilizes valuation techniques that maximize the use of observable inputs and minimize the use of unobservable inputs to the extent possible. The Company determines fair value based on assumptions that market participants would use in pricing an asset or liability in the principal or most advantageous market. When considering market participant assumptions in fair value measurements, the following fair value hierarchy distinguishes between observable and unobservable inputs, which are categorized in one of the following levels:

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Level 1 Inputs: Unadjusted quoted prices in active markets for identical assets or liabilities accessible to the reporting entity at the measurement date.

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Level 2 Inputs: Other than quoted prices included in Level 1 inputs that are observable for the asset or liability, either directly or indirectly, for substantially the full term of the asset or liability.

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Level 3 Inputs: Unobservable inputs for the asset or liability used to measure fair value to the extent that observable inputs are not available, thereby allowing for situations in which there is little, if any, market activity for the asset or liability at measurement date.

On a recurring basis, the Company measures certain financial assets and liabilities at fair value. The following tables summarize the fair value of the Company’s financial assets and liabilities measured at fair value on a recurring basis by level within the fair value hierarchy (in thousands):

All of the investments held as of December 31, 2023 had original maturities of less thantwo years. As of December 31, 2023, all of the investments are scheduled to mature in 12 months.

For the years ended December 31, 2023 and 2022, the Company recognized no material realized gains or losses on financial instruments.

Balance Sheet Components

Prepaid Expenses and Other Current Assets

Prepaid expenses and other current assets consisted of the following (in thousands):

Property and Equipment, Net

Property and equipment, net consisted of the following (in thousands):

Total depreciation expense recognized for each of the years ended December 31, 2023 and 2022 was$2.1 million.

Accrued Liabilities

Accrued liabilities consisted of the following (in thousands):

Commitments and Contingencies

Leases

The Company leases its offices and laboratory in Brisbane, California, or the Brisbane Lease, under aten-year noncancelable lease agreement that ends in October 2031 with aten-year renewable option. In November 2021, the Company subleased unoccupied space for two years starting from December 2021 through November 2023, for aggregate sublease payments of $3.4 million. The sublease income, while it reduces the rent expense, is not considered in the value of the right-of-use assets or lease liabilities. The Company’s sublease income was$2.0 million and $2.1 million for the years ended December 31, 2023 and 2022, respectively.

As of December 31, 2023, the operating lease right-of-use assets were$18.0 million and lease liabilities were$31.4 million in the consolidated balance sheet. The weighted average remaining lease term is 7.8 years.

The weighted average incremental borrowing rate used to measure the operating lease liability is 8.4%.

Operating lease cost for the years ended December 31, 2023 and 2022 was$2.3 million and $2.1 million, respectively. Variable lease payments for the years ended December 31, 2023 and 2022 were$1.5 million and $1.0 million, respectively.

Future minimum lease payments and related lease liabilities as of December 31, 2023 were as follows:

License and Other Agreements

In November 2011, the Company entered into an exclusive licensing agreement, or the Stanford Agreement, with The Board of Trustees of the Leland Stanford Junior University, or Stanford, whereby the Company was granted an exclusive, worldwide, royalty-bearing, sublicensable license, under certain patent rights, or the Licensed Patents, to make, use, offer for sale, sell, import and otherwise commercialize products covered by the Licensed Patents for human or animal diseases, disorders or conditions. Under the Stanford Agreement, the Company made an upfront payment and is obligated to pay Stanford annual license maintenance fees, potential future milestone payments totaling up to $0.5 million, and royalty payments at a rate equal to a low single-digit percentage of worldwide net sales of licensed products. The Company did not achieve any milestones or make any milestone payments for the years ended December 31, 2023 and 2022.

In December 2016, the Company entered into a Sponsored Research Agreement with a not-for-profit entity to perform research on multiple sclerosis. The Sponsored Research Agreement was amended in March 2019. Under the terms of the Sponsored Research Agreement, as amended, the Company may receive up to $0.7 million in funding. If, within 15 years of the end of the Sponsored Research Agreement, the Company files a marketing authorization application for a product treating multiple sclerosis, the Company will be obligated to pay milestone payments up to four times the amounts received under the Sponsored Research Agreement. The Company has received $0.6 million in funding to date, which was recorded as interest and other income. The Company recognizedno income during the years ended December 31, 2023 and 2022.

Guarantees and Indemnifications

In the normal course of business, the Company enters into agreements that contain a variety of representations and provide for general indemnification. The Company’s exposure under these agreements is unknown because it involves claims that may be made against the Company in the future. To date, the Company hasnot paid any claims or been required to defend any action related to its indemnification obligations. As of December 31, 2023, the Company didnot have any material indemnification claims that were probable or reasonably possible and consequently has not recorded related liabilities.

Stockholder’s Equity

2023 Financing

In December 2023, the Company raised net proceeds of approximately$117.0 million after deducting underwriting discounts and offering expenses through the sale of 25,035,000 shares of the Company’s common stock, par value $0.001 per share at a price of $2.880 per share and pre-funded warrants to purchase an aggregate of 18,379,861 shares of common stock at a price of $2.879 per share, which equals the per share offering price for the shares of common stock less the $0.001 exercise price for each pre-funded warrant. An entity related to one of the Company’s directors participated in the public offering and purchased 350,000 shares of common stock for an aggregate price of approximately $1.0 million. The warrants meet the criteria for equity classification and were therefore recorded at fair value as of the grant date as a component of stockholders’ equity within additional paid-in capital in the amount of $52.9 million.

As of December 31, 2023, pre-funded warrants to purchase up to 18,379,861 shares of common stock remained outstanding from the 2023 financing.

2022 Financing

In July 2022, the Company raised net proceeds of approximately $122.5 million after deducting fees and expenses through the sale of an aggregate of 9,013,834 shares of common stock, pre-funded warrants to purchase up to 24,696,206 shares of its common stock and accompanying common warrants to purchase up to 8,427,508 shares of its common stock. The offering price per share and accompanying common warrant was $3.87125 per share and the offering price per pre-funded warrant and accompanying common warrant was $3.87025 per share, which equals the per share offering price for the shares of common stock less the $0.001 exercise price for each such pre-funded warrant. The pre-funded warrants remain exercisable until exercised in full. The common warrants have an exercise price of $5.806875 per share and expire on June 30, 2025. Both the pre-funded and common warrants are immediately exercisable, subject to beneficial ownership limitations. The warrants meet the criteria for equity classification and were therefore recorded at fair value as of the grant date as a component of stockholders’ equity within additional paid-in capital.

In 2023, the Company issued an aggregate of 2,582,557 shares of common stock upon the cashless exercise of pre-funded warrants to purchase 2,583,144 shares of common stock. As of December 31, 2023, pre-funded warrants to purchase up to 22,113,062 shares of common stock and common warrants to purchase up to 8,427,508 shares of common stock remained outstanding from the 2022 financing.

2021 At-the-Market (ATM) Program

In August 2021, the Company entered into a sales agreement with TD Cowen as sales agent, pursuant to which the Company may issue and sell shares of its common stock for an aggregate maximum offering of $100.0 million under an at-the-market offering program, or 2021 ATM program. TD Cowen is entitled to compensation up to 3% of the aggregate gross proceeds for the common stock sold through the 2021 ATM program. During 2023, the Company sold 2,646,458 shares of common stock at a price of $6.80 per share under the 2021 ATM program for net proceeds of approximately $17.5 million after deducting commissions paid to TD Cowen as sales agent. Subsequent to December 31, 2023 and through the date of issuance of these financial statements, net proceeds of approximately $32.3 million were raised as a result of the sale of shares of the Company’s common stock through the 2021 ATM program. As of December 31, 2023, and as of the date of issuance of these financial statements, approximately $82.0 million and $48.9 million, respectively, remained available for the offer and sales of shares of common stock under the 2021 ATM program.

2024 ATM Program

In March 2024, the Company entered into a sales agreement with TD Cowen, as sales agent, or 2024 ATM program, pursuant to which the Company may issue and sell shares of its common stock for an aggregate maximum offering of $100.0 million. TD Cowenis entitled to compensation up to 3% of the aggregate gross proceeds for the common stock sold through the 2024 ATM program. As of the date of issuance of these financial statements, the Company has not made any sales under the 2024 ATM program.

Common Stock

The holders of the Company’s common stock have one vote for each share of common stock. Common stockholders are entitled to dividends when, as, and if declared by the board of directors. The holders have no preemptive or other subscription rights and there are no redemption or sinking fund provisions with respect to such shares. As of December 31, 2023, no dividends had been declared by the board of directors.

The Company reserved the following shares of common stock for issuance as follows:

Equity Incentive Plan

In July 2020, the Company’s board of directors and stockholders adopted and approved the 2020 Incentive Award Plan, or the 2020 Plan, and the Employee Stock Purchase Plan, or the ESPP, which became effective in connection with the IPO.

The Company may not grant any additional awards under the 2011 Equity Incentive Plan, or the 2011 Plan. The 2011 Plan will continue to govern outstanding equity awards granted thereunder.

2020 Equity Incentive Plan

The number of shares of common stock reserved for issuance under the 2020 Plan automatically increase on the first day of January, in an amount equal to 4% of the total number of shares of the Company’s capital stock outstanding on the last day of the preceding year, or a lesser number of shares determined by the Company’s board of directors.

Awards granted under the 2020 Plan expire no later thanten years from the date of grant. For the Incentive Stock Options, or ISOs, and Nonstatutory Stock Options, or NSOs, the option price shall not be less than 100% of the estimated fair value on the date of grant. Options granted typically vest over afour-year period but may be granted with different vesting terms. As of December 31, 2023 and 2022, there were 1,988,340 and 478,109 shares available for issuance under the 2020 Plan, respectively.

2022 Employment Inducement Award Plan

In July 2022, the Company’s board of directors adopted the Annexon, Inc. 2022 Employment Inducement Award Plan, or the Inducement Plan, and together with the 2011 Plan and the 2020 Plan, the Plans. The Inducement Plan was adopted by the Company’s board of directors without stockholder approval pursuant to Nasdaq Marketplace Rule 5635(c)(4), or Rule 5635(c)(4). In accordance with Rule 5635(c)(4), awards made under the Inducement Plan may only be granted to newly hired employees as an inducement material to the employees entering into employment with the Company. Awards granted under the Inducement Plan expire no later than ten years from the date of grant. An aggregate of 2,000,000 shares of common stock were reserved for issuance under the Inducement Plan. As of December 31, 2023 and 2022, there were 758,084 and 1,610,600 shares available for issuance under the Inducement Plan, respectively.

Stock options

The following table presents stock option activity under the Plans for the period:

The total intrinsic value of options exercised during the years ended December 31, 2023 and 2022 was$0.3 million and $11,500, respectively. The intrinsic value is the difference between the fair value of the Company’s common stock at the time of exercise and the exercise price of the stock option.

The weighted-average grant date fair value of options granted to employees during the years ended December 31, 2023 and 2022 was$3.72 and$3.94 per share, respectively.

As of December 31, 2023, the total unrecognized stock-based compensation cost related to outstanding unvested stock options was$23.1 million, which the Company expects to recognize over an estimated weighted-average period of 2.1 years.

Restricted Stock Units

RSUs are share awards that entitle the holder to receive freely tradeable shares of the Company’s common stock upon vesting. The RSUs cannot be transferred and the awards are subject to forfeiture if the holder’s employment terminates prior to the release of the vesting restrictions. The RSUs generally vest over a three-year period in equal amounts on an annual basis, provided the employee remains continuously employed with the Company. The fair value of the RSUs is equal to the closing price of the Company’s common stock on the grant date.

A summary of RSU activity under our equity incentive plan and related information is as follows:

As of December 31, 2023, unrecognized stock-based compensation expense related to outstanding unvested RSUs was$1.9 million, which is expected to be recognized over a weighted-average period of 1.7 years.

Employee Stock Purchase Plan

The ESPP enables eligible employees to purchase shares of the Company’s common stock at the end of each offering period at a price equal to 85% of the fair market value of the shares on the first business day or the last business day of the offering period, whichever is lower. Eligible employees generally included all employees. Share purchases are funded through payroll deductions of at least 1%, and up to 15%of an employee’s eligible compensation foreach payroll period. The number of shares reserved for issuance under the ESPP increase automatically on the first day of each fiscal year, by a number equal to,1% of the shares of common stock outstanding on the last day of the immediately preceding fiscal year, or such number of shares determined by the Company’s board of directors. As of December 31, 2023,1,338,381 shares were available for future purchase. The ESPP generally provides for six-month consecutive offering periods beginning on May 15 th and November 15 th of each year. The ESPP is a compensatory plan as defined by the authoritative guidance for stock compensation. As such, stock-based compensation expense has been recorded for the years ended December 31, 2023 and 2022.

The stock-based compensation expense related to the ESPP for the years ended December 31, 2023 and 2022 was$0.3 million and $0.1 million, respectively.

Stock-Based Compensation Expense

The total stock-based compensation expense recognized was as follows (in thousands):

To determine the value of stock option awards for stock-based compensation purposes, the Company uses the Black-Scholes option pricing model and the assumptions discussed below. Each of these inputs is subjective and generally requires significant judgment.

Fair Value of Common Stock—The fair value of each share of underlying common stock is based on the closing price of the Company’s common stock as reported on the date of grant on the Nasdaq Global Select Market.

Expected Term—The expected term represents the period that the stock-based awards are expected to be outstanding and is determined using the simplified method (based on the mid-point between the vesting date and the end of the contractual term). The Company continues using the simplified method as it does not have sufficient historical exercise data to provide a reasonable basis upon which to estimate expected term due to the limited period of time its equity shares have been publicly traded.

Expected Volatility—Because the Company does not have sufficient trading history for its common stock, the expected volatility was estimated based on the average volatility for comparable publicly traded life sciences companies over a period equal to the expected term of the stock option grants. The comparable companies were chosen based on the similar size, stage in life cycle or area of specialty.

Risk-Free Interest Rate—The risk-free interest rate is based on the U.S. Treasury zero coupon issues in effect at the time of grant for periods corresponding with the expected term of the option.

Dividend Yield—The Company has never paid dividends on its common stock and has no plans to pay dividends on its common stock. Therefore, the Company used an expected dividend yield of zero.

The fair value of each stock option issued was estimated on the date of grant using the Black-Scholes option pricing model with the following assumptions:

Income Taxes

For financial reporting purposes, loss before provision for income taxes, includes the following components (in thousands):

For each of the years ended December 31, 2023 and 2022, the Company incurred insignificant amounts for an income tax provision. The U.S. federal and California deferred tax assets generated from the Company’s net operating losses have been fully reserved, as the Company believes it is not more likely than not that the benefit will be realized.

Reconciliation of income tax computed at federal statutory rates to the reported provision for income taxes was as follows (in thousands):

Deferred Tax Assets and Liabilities

The tax effects of temporary differences that give rise to significant portions of the Company’s deferred tax assets and liabilities are as follows (in thousands):

As of December 31, 2023, the Company had $321.9 million of federal and $71.3 million of state net operating loss, or NOL, carryforwards available to offset future taxable income. Under the Tax Cuts and Jobs Act of 2017, or the Tax Act, federal NOLs generated after December 31, 2017 will be carried forward indefinitely with the yearly NOL utilization limited to 80% of taxable income. The Company has $278.8 million of such federal NOLs that do not expire. If not utilized, the federal carryforward losses generated prior to 2018 and the state carryforward losses will expire in various amounts beginning in 2031.

As of December 31, 2023, the Company had approximately $15.7 million of federal and $8.0 million of state credit carryforwards available to offset future taxable income. If not utilized, these credit carryforwards will expire in various amounts for federal purposes beginning in 2031. The state credits do not expire.

In assessing the realization of deferred tax assets, management considers whether it is more likely than not some portion or all of the deferred tax assets will not be realized. Management believes that, based on available evidence, both positive and negative, it is more likely than not that the deferred tax assets will not be utilized; therefore, a full valuation allowance has been recorded. The Company’s valuation allowance increased by $30.2 million and $31.6 million for the years ended December 31, 2023 and 2022, respectively. The changes in the 2023 valuation allowance were primarily due to the addition of capitalized research and development costs, current year loss carryforwards and research and development credits. The changes in the 2022 valuation allowance were primarily due to the addition of the current year loss carryforwards and research and development credits.

Utilization of the net operating loss carryforwards and credits may be subject to an annual limitation due to the ownership change limitations provided by the Internal Revenue Code of 1986, as amended and similar state provisions. The annual limitations may result in the expiration of net operating losses and credits before utilization. The Company performed a Section 382 analysis through December 31, 2023. Federal net operating loss carryforwards of $321.8 million and state and local net operating loss carryforwards of $36.6 million are not expected to expire unutilized as a result of ownership changes identified through December 31, 2023. The Company has identified $0.1 million and $34.7 million of federal and state net operating losses, respectively, that will expire unused due to ownership changes, and federal credits of $3.7 million that will not be able to be utilized due to ownership change limitation; these amounts have been excluded from the deferred tax assets table above. Further ownership changes subsequent to December 31,2023 may be identified which could result in limitations to the amount of net operating losses and credits which may be utilized prior to expiration.

Uncertain Tax Benefits

The Company has the following activity relating to the gross amount of unrecognized tax benefits (in thousands):

None of these uncertain tax positions will impact the Company’s effective tax rate if assessed. The Company’s policy is to classify interest and penalties associated with unrecognized tax benefits as income tax expense. The Company hadno interest or penalty accruals associated with uncertain tax benefits in its consolidated balance sheet and consolidated statement of operations for the years ended December 31, 2023 and 2022. The Company files income tax returns in the United States, California, Georgia, Indiana, Maryland, Massachusetts, Nebraska, New Jersey, North Carolina, Pennsylvania, Tennessee, Texas and Australia. The Company is not currently under examination by any major tax jurisdictions nor has it been in the past. The tax years 2011 through 2023 remain effectively open for examination by the Internal Revenue Service and most state tax authorities because of net operating losses and credit carryovers.

Although it is reasonably possible that certain unrecognized tax benefits may increase or decrease within the next twelve months due to tax examination changes, settlement activities, expirations of statute of limitations, or the impact on recognition and measurement considerations related to the results of published tax cases or other similar activities, the Company does not anticipate any significant changes to unrecognized tax benefits over the next 12 months.

Net Loss Per Share

The Company calculates basic net loss per share by dividing net loss by the weighted-average number of shares of common stock outstanding, excluding restricted common stock. The weighted-average number of shares of common stock used in the basic and diluted net loss per share calculation include pre-funded warrants to purchase up to 40,492,923 shares of common stock, as the pre-funded warrants are exercisable at any time for nominal cash consideration. The Company has generated a net loss in all periods presented, so the basic and diluted net loss per share are the same, as the inclusion of the potentially dilutive securities would be anti-dilutive.

The following outstanding potentially dilutive shares have been excluded from the calculation of diluted net loss per share due to their anti-dilutive effect: