Arcturus Therapeutics Holdings Inc.

Note 1. Organization

Description of Business

Arcturus Therapeutics Holdings Inc. (the “Company” or "Arcturus") is a messenger RNA medicines company focused on the development of liver and respiratory rare disease therapeutics. Arcturus became a clinical stage company in 2020 when it announced that its Investigational New Drug (“IND”) application for ornithine transcarbamylase (“OTC”) deficiency and its Clinical Trial Application (“CTA”) for candidate LUNAR-COV19 were approved by applicable health authorities. In 2023, our COVID-19 vaccine, ARCT-154 (also referred to as KOSTAIVE®), received marketing authorization approval in Japan foradults 18 years and older, and in September 2024 KOSTAIVE became the world’s first approved and commercially available self-amplifying RNA (sa-mRNA) vaccine.

Note 2. Summary of Significant Accounting Policies

Basis of Presentation and Principles of Consolidation

The accompanying consolidated financial statements include the accounts of Arcturus Therapeutics Holdings Inc. and its subsidiaries. All intercompany accounts and transactions have been eliminated in consolidation. These consolidated financial statements are prepared in conformity with accounting principles generally accepted in the United States (“U.S. GAAP”), which requires management to make estimates and assumptions regarding the valuation of certain debt and equity instruments, the equity method investment, share-based compensation, accruals for liabilities, income taxes, revenue and deferred revenue, leases, expense accruals, and other matters 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 amounts of revenues and expenses during the reporting period. Although these estimates are based on management’s knowledge of current events and actions the Company may undertake in the future, actual results could materially differ from those estimates.

Segment Information

Operating segments are identified as components of an enterprise about which separate discrete financial information is available for evaluation by the chief operating decision-maker in making decisions regarding resource allocation and assessing performance. The Company and its chief operating decision-maker view the Company’s operations and manage its business inone operating segment, which includes all activities related to the discovery, development and commercialization of messenger RNA medicines.

Cash and Cash Equivalents

Cash equivalents are short-term highly liquid investments that are readily convertible to cash with original maturities of three months or less at the date of purchase.

Restricted cash

Restricted cash includes cash required to be set aside as security for lease payments and to maintain a letter of credit for the benefit of the landlord for the Company’s offices. At December 31, 2025 and 2024, the Company had restricted cash of $1.9 million inconjunction with property leases in San Diego, California, and such restriction is expected to be removed at the end of the lease term.

Fair Value Measurements

Fair value is defined as the exit price, or the amount that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants as of the measurement date. A hierarchy has been established for inputs used in measuring fair value that maximizes the use of observable inputs and minimizes the use of unobservable inputs by requiring that the most observable inputs be used when available.

Observable inputs are inputs that market participants would use in valuing the asset or liability developed based on market data obtained from sources independent of the Company. Unobservable inputs are inputs that reflect the Company’s assumptions about the factors market participants would use in valuing the asset or liability developed based upon the best information available under the circumstances. The hierarchy consists of three levels. Level 1 inputs are quoted prices (unadjusted) in active markets for identical assets or liabilities. Level 2 inputs include quoted prices for similar assets or liabilities in active markets, quoted prices for identical or similar assets or liabilities in markets that are not active, and inputs (other than quoted prices) that are observable for the asset or liability, either directly or indirectly. Level 3 inputs are unobservable inputs for the asset or liability. Categorization within the valuation hierarchy is based upon the lowest level of input that is significant to the fair value measurement.

Accounts Receivable

Accounts receivable are recorded at the net invoice value and are non-interest bearing. The Company considers receivables past due based on the contractual payment terms. The Company reserves for specific receivables if collectability is no longer reasonably assured. Estimates for allowances for doubtful accounts are determined based on existing contractual obligations, historical payment patterns, and individual customer circumstances. The Company reevaluates such reserves on a regular basis and adjusts its reserves as needed. Once a receivable is deemed to be uncollectible, such balance is charged against the reserve. No reserves have been recorded as of December 31,2025 or 2024.

Concentration of Credit Risk and Significant Customers

The Company is exposed to concentrations of credit risk primarily related to cash, cash equivalents, and accounts receivable.

Cash and Cash Equivalents

The Company mitigates credit risk exposure by maintaining cash and cash equivalents only with high-credit-quality financial institutions and investing in instruments with short maturities. The Company continuously monitors counterparty risk to minimize potential financial exposure.

Accounts Receivable Concentration

As of December 31, 2025 and 2024, the Company had significant concentrations of credit risk related to accounts receivable from a limited number of customers. The following customers accounted for 10% or more of total accounts receivable in each respective period:

As of December 31, 2025:

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BARDA –64% of total accounts receivable

•

CSL –19% of total accounts receivable

As of December 31, 2024:

•

BARDA –60% of total accounts receivable

•

CSL –20% of total accounts receivable

The Company monitors its credit exposure through regular assessments of counterparty risk and maintains ongoing collection efforts to mitigate potential credit losses.

Revenue Concentration

The Company generates a substantial portion of its revenue from a limited number of key customers. The following customers accounted for 10% or more of total revenue for each period:

For the year ended December 31, 2025:

•

CSL –80% of total revenue

•

BARDA –16% of total revenue

For the year ended December 31, 2024:

•

CSL –91% of total revenue

For the year ended December 31, 2023:

•

CSL –92% of total revenue

Given this concentration, the Company’s financial performance and cash flows may be materially impacted if there are changes in demand, contract renewals, or the financial condition of these key customers. The Company continues to evaluate opportunities to expand its customer base and mitigate concentration risk over time.

Joint Ventures, Equity Method Investments and Variable Interest Entities

Investments for which the Company exercises significant influence, but does not have control are accounted for under the equity method. Equity method investment activity is related to the Company's joint venture in ARCALIS, Inc. with Axcelead, Inc. The Company’s share of the investees’ results is presented as either income or loss from equity method investees in the accompanying consolidated statements of operations and comprehensive loss. As of December 31, 2025, the carrying value of the equity-method investment in ARCALIS remained atzero.

Property and Equipment, net

Property and equipment are stated at cost, net of accumulated depreciation and amortization. The cost of property and equipment is depreciated or amortized using the straight-line method over the respective useful lives of the assets, ranging from three tofive years. Leasehold improvements are amortized using the straight-line method over the shorter of the estimated useful life of the asset or the lease term. Long-lived assets, including property and equipment are reviewed for impairment whenever events or circumstances indicate that the carrying amount of these assets may not be recoverable. The determinants used for this evaluation include management’s estimate of an asset’s ability to generate positive income from operations and positive cash flow in future periods, as well as the strategic significance of the assets to the Company’s business objectives. The Company didnot recognize any impairment losses for the years ended December 31,2025, 2024 or 2023.

Comprehensive Loss

Comprehensive loss is defined as the change in stockholders’ equity during a period from transactions and other events and circumstances from non-owner sources. There wasno other comprehensive loss or income tax effect related to unrealized losses in the years ended December 31,2025, 2024 or 2023.

Revenue Recognition

At contract inception, the Company analyzes its collaboration arrangements to assess whether such arrangements involve joint operating activities performed by parties that are both active participants in the activities and exposed to significant risks and rewards dependent on the commercial success of such activities and therefore within the scope of ASC Topic 808, Collaborative Arrangements (ASC 808). For collaboration arrangements within the scope of ASC 808 that contain multiple elements, the Company first determines which elements of the collaboration reflect a vendor-customer relationship and are therefore within the scope of ASC 606.

The Company determines revenue recognition for arrangements within the scope of Topic 606 by performing the following five steps: (i) identify the contract; (ii) identify the performance obligations in the contract; (iii) determine the transaction price; (iv) allocate the transaction price to the performance obligations in the contract; and (v) recognize revenue when, or as, the company satisfies a performance obligation.

The terms of the Company’s revenue agreements include license fees, upfront payments, milestone payments, reimbursement for research and development activities, option exercise fees, consulting and related technology transfer fees and royalties on sales of commercialized products. The event-based milestone payments represent variable consideration, and the Company uses the most likely amount method to estimate this variable consideration because the Company will either receive the milestone payment or will not, which makes the potential milestone payment a binary event. The most likely amount method requires the Company to determine the likelihood of earning the milestone payment. Given the high degree of uncertainty around achievement of these milestones, the Company determines the milestone amounts to be fully constrained and does not recognize revenue until the uncertainty associated with these payments is resolved. The Company will recognize revenue from sales-based royalty payments when or as the sales occur. The Company will re-evaluate the transaction price in each reporting period as uncertain events are resolved and other changes in circumstances occur.

A performance obligation is a promise in a contract to transfer a distinct good or service to the collaborative partner and is the unit of account in Topic 606. A contract’s transaction price is allocated to each distinct performance obligation based on relative standalone selling price and recognized as revenue when, or as, the performance obligation is satisfied.

For performance obligations that are recognized over time, the Company measures the progress using an input method. The input methods used are based on the effort expended or costs incurred toward the satisfaction of the performance obligation. The Company estimates the amount of effort expended, including the time estimated it will take to complete the activities, or costs incurred in a given period, relative to the estimated total effort or costs to satisfy the performance obligation. This approach requires the Company to make numerous estimates and use significant judgment. If estimates or judgments change over the course of the collaboration, a cumulative catch up of revenue is recognized in the period such changes are identified.

See“Note 3, Revenue” for specific details surrounding the Company’s arrangements.

Grant revenue

Grant revenue consists of funding under cost reimbursement programs primarily from federal and non-profit foundation sources for qualified research and development activities performed by the Company. Such amounts are invoiced and recorded as revenue as grant-funded activities are performed, with any advance funding recorded as deferred revenue until the activities are performed.

Leases

The Company determines if an arrangement is a lease at inception. Lease right-of-use 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. For operating leases with an initial term greater than 12 months, the Company recognizes operating lease right-of-use assets and operating lease liabilities based on the present value of lease payments over the lease term at the commencement date. Operating lease right-of-use assets are comprised of the lease liability plus any lease payments made and excludes lease incentives. Lease terms include options to renew or terminate the lease when the Company is reasonably certain that the renewal option will be exercised or when it is reasonably certain that the termination option will not be exercised. For the Company's operating leases, if the interest rate used to determine the present value of future lease payments is not readily determinable, the Company estimates its incremental borrowing rate as the discount rate for the lease. The Company's incremental borrowing rate is estimated to approximate the interest rate on a collateralized basis with similar terms and payments, and in similar economic environments. Lease expense for lease payments is recognized on a straight-line basis over the lease term. The Company has elected the practical expedient to not separate lease and non-lease components.

See“Note 11, Commitments and Contingencies” for specific details surrounding the Company’s leases.

Research and Development Costs, net

All research and development costs are expensed as incurred. Research and development costs consist primarily of salaries, employee benefits, costs associated with preclinical studies and clinical trials (including amounts paid to clinical research organizations and other professional services), pre-launch inventory, in-process research and development expenses and license agreement expenses. Payments made prior to the receipt of goods or services to be used in research and development are capitalized until the goods are received or the services are performed. The Company recognizes grants that fall within the scope of ASC 808 as contra research and development expense in the consolidated statement of operations on a systematic basis over the periods in which the entity recognizes as expenses the related costs for which the grants are intended to compensate.

The Company records accruals for estimated research and development costs, comprising payments for work performed by third party contractors, laboratories, participating clinical trial sites, and others. Some of these contractors bill monthly based on actual services performed, while others bill periodically based upon achieving certain contractual milestones. For the latter, the Company accrues the expenses as goods or services are used or rendered.

Clinical trial activities performed by third parties are accrued and expensed based upon estimates of the proportion of work completed over the life of the individual clinical trial and patient enrollment rates in accordance with agreements established with Clinical Research Organizations (“CROs”) and clinical trial sites. Estimates are determined by reviewing contracts, vendor agreements and purchase orders, and through discussions with internal clinical personnel and external service providers as to the progress or stage of completion of trials or services and the agreed-upon fee to be paid for such services.

General and Administrative Costs

General and administrative expenses consist primarily of personnel-related costs, including share-based compensation, for executives, finance, legal, human resources, business development, and other administrative and operational functions, professional fees, accounting and legal services, information technology and facility-related costs, and expenses associated with obtaining and maintaining intellectual property (“IP”). These costs relate to the operation of the business, unrelated to the research and development function, or any individual program.

Pre-Launch Inventory

Prior to obtaining initial regulatory approval for an investigational product candidate, the Company expenses costs relating to production of inventory as research and development expense in its consolidated statements of operations and comprehensive loss, in the period incurred. When the Company believes regulatory approval and subsequent commercialization of an investigational product candidate is probable, and the Company also expects future economic benefit from the sales of the investigational product candidate to be realized, it will then capitalize the costs of production as inventory.

Share-Based Compensation

The Company records share-based compensation for equity awards granted to employees, consultants, officers and directors within general and administrative and research and development expenses on the statements of operations and comprehensive loss. Share-based compensation is recognized over the requisite service period of the individual awards using the straight-line attribution method, which generally equals the vesting period. Employees and officers’ stock options have aten-year life and generally vest 25% on the first anniversary of the grant and in 1/36 th equal installments on each monthly anniversary thereafter, such that options are fully vested on thefour-year anniversary of the date of grant. The exercisability and vesting periods of equity awards granted to consultants and directors vary.

The fair value of stock options is estimated using a Black-Scholes valuation model on the date of grant. This method requires certain assumptions be used as inputs, such as the fair value of the underlying common stock, expected term of the option before exercise, expected volatility of the Company’s common stock, expected dividend yield, and a risk-free interest rate. The Company has limited historical stock option activity and therefore estimates the expected term of stock options granted using the simplified method, which represents the average of the contractual term of the stock option and its weighted-average vesting period. Through the third quarter of 2024, the Company estimated expected volatility using the historical volatility of a peer group of publicly traded companies. Beginning in the fourth quarter of 2024 and continuing into fiscal year 2025, the Company used its own historical volatility to estimate expected volatility, as it had accumulated sufficient trading history and stock price data to support the use of Company‑specific volatility. The Company has not declared or paid any dividends and does notcurrently expect to do so in the foreseeable future. The risk-free interest rates used are based on the implied yield currently available in United States Treasury securities at maturity with a term equivalent to the expected term of the stock options. The effect of forfeited or cancelled awards is recorded when the forfeiture or cancellation occurs.

Statement of Cash Flows

The following table provides a reconciliation of cash and cash equivalents and restricted cash reported within the consolidated balance sheets to the total of such amounts shown in the consolidated statement of cash flows:

Income Tax Expense

Income taxes are accounted for using an asset and liability approach that requires the recognition of deferred tax assets and liabilities for the expected future tax consequences of temporary differences between the financial reporting basis and the tax basis of the Company’s assets and liabilities at the applicable tax rates, along with net operating loss and tax credit carryovers. The Company records a valuation allowance against its deferred tax assets to reduce the net carrying value to an amount that it believes is more likely than not to be realized. Management has considered estimated taxable income and ongoing prudent and feasible tax planning strategies in assessing the amount of the valuation allowance. Based upon the weight of available evidence, which includes the Company’s historical operating performance and limited potential to utilize tax attribute carryforwards, the Company has determined that total deferred tax assets should be fully offset by a valuation allowance. When the Company establishes or reduces the valuation allowance against its deferred tax assets, its provision for income taxes will increase or decrease, respectively, in the period such determination is made.

The Company is required to file federal and state income tax returns in the United States and various other state jurisdictions. The Company also files income tax returns in the foreign countries in which it operates. The preparation of these income tax returns requires the Company to interpret the applicable tax laws and regulations in effect in such jurisdictions, which could affect the amount of tax paid by the Company.

Additionally, the Company follows an accounting standard addressing the accounting for uncertainty in income taxes that prescribes rules for recognition, measurement, and classification in the consolidated financial statements of tax positions taken or expected to be taken in a tax return.

Net Loss per Share

Basic net loss per share is calculated by dividing the net loss by the weighted-average number of shares of common stock outstanding for the period, without consideration for common stock equivalents. Diluted net loss per share is calculated by dividing the net loss by the weighted-average number of shares of common stock and dilutive common stock equivalents outstanding for the period determined using the treasury-stock method. Dilutive shares of common stock for the years ended December 31, 2025, 2024 and 2023 were comprised of stock options and restricted stock units.

No dividends were declared or paid during the reporting periods.

Recently Adopted Accounting Pronouncements

In November 2023, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2023-07, Segment Reporting (Topic 280): Improvements to Reportable Segment Disclosures, which requires public entities to disclose information about their reportable segments’ significant expenses and other segment items on an interim and annual basis. Public entities with a single reportable segment are required to apply the disclosure requirements in ASU 2023-07, as well as all existing segment disclosures and reconciliation requirements in ASC 280 on an interim and annual basis. The Company adopted ASU 2023-07 for annual reporting periods beginning January 1, 2024 and interim reporting periods beginning January 1, 2025. The adoption of ASU 2023-07 hadno significant impact on our financial statement disclosures. See “Note 12, Segment Information” for further information.

In December 2023, the FASB issued ASU 2023-09, Income Taxes (Topic 740) - Improvements to Income Tax Disclosures. The new standard requires a company to expand its existing income tax disclosures, specifically related to the rate reconciliation and income taxes paid. The Company adopted ASU 2023-09 prospectively beginning in fiscal year 2025. See “Note 10, Income Taxes” for further information.

Recently Issued Accounting Standards Not Yet Adopted

From time to time, new accounting pronouncements are issued by the FASB or other standard setting bodies and adopted by the Company as of the specified effective date. The Company believes that the impact of recently issued standards that are not yet effective will not have a material impact on the consolidated financial statements and disclosures.

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 requires public entities to disclose specified information about certain costs and expenses on an interim and annual basis. ASU 2024-03 is effective for annual reporting periods beginning after December 15, 2026, and interim reporting periods beginning after December 15, 2027, with early adoption permitted. The Company is currently evaluating the impact that adoption of ASU 2024-03 will have on the financial statement disclosures.

NOTE 3. Revenue

The Company has entered into license agreements and collaborative research and development arrangements with pharmaceutical and biotechnology companies, as well as consulting, related technology transfer, product revenue and government grant agreements. Under these arrangements, the Company is entitled to receive license fees, consulting fees, product fees, technological transfer fees, upfront payments, milestone payments if and when certain research and development milestones, technology transfer milestones or success-based milestones are achieved, royalties on approved product sales and reimbursement for research and development activities. The Company’s costs of performing these services are included within research and development expenses. The Company’s milestone payments are typically defined by achievement of certain preclinical, clinical, and commercial success criteria. Preclinical milestones may include in vivo proof of concept in disease animal models, lead candidate identification, and completion of IND-enabling toxicology studies. Clinical milestones may, for example, include successful enrollment of the first patient in or completion of Phase 1, 2 and 3 clinical trials, and commercial milestones are often tiered based on net or aggregate sale amounts. The Company cannot guarantee the achievement of these milestones due to risks associated with preclinical and clinical activities required for development of nucleic acid medicine-based therapeutics and vaccines.

The following table presents changes in the balances of receivables and contract liabilities related to revenue generating agreements during the year ended December 31,2025:

During the year ended December 31, 2025, the Company recognized $26.4 million in revenue from the deferred revenue balance as of December 31, 2024.

The following table summarizes the Company’s revenue for the periods indicated. Approximately $67.1 million, $138.4 million and $154.9 million of total revenue represents revenue derived from foreign countries for the years ended December 31, 2025, 2024 and 2023, respectively.

Accounts receivable is comprised of the following as of December 31, 2025 and 2024:

Billed accounts receivable represent amounts invoiced under the Company’s collaboration and reimbursement arrangements that remain outstanding. Unbilled accounts receivable represent reimbursable costs incurred or revenue recognized for which invoices have not yet been issued as of the balance sheet date in accordance with contractual billing terms. Substantially all unbilled accounts receivable are expected to be billed and collected within 12 months.

The following paragraphs provide information regarding the nature and purpose of the Company’s most significant revenue arrangements.

CSL Seqirus

On November 1, 2022, the Company entered into a Collaboration and License Agreement (as amended, the “CSL Collaboration Agreement”) with Seqirus, Inc., a part of CSL Limited (“CSL Seqirus”), for the global exclusive rights to research, develop, manufacture, and commercialize vaccines. Under the terms of the CSL Collaboration Agreement, the Company provides CSL Seqirus with an exclusive global license to its mRNA technology (including STARR®) and LUNAR® lipid-mediated delivery, along with mRNA drug substance and drug product manufacturing processes. CSL Seqirus will lead the development and commercialization of vaccines under the collaboration. The collaboration plans to advance vaccines against SARS-CoV-2 (COVID-19), influenza, pandemic preparedness as well as three other infectious diseases. In September 2024, our COVID-19 vaccine

KOSTAIVE® became the world’s first approved and commercially available self-amplifying RNA (sa-mRNA) vaccine.

The Company received a $200.0 million upfront payment and is eligible to receive over $1.3 billion in development milestones if all products are registered in the licensed fields and is entitled to potentially receive up to $3.0 billion in commercial milestones based on “net sales” of vaccines in the various fields. In addition, the Company is eligible to receive a 40% net profit share for COVID-19 vaccine products and up to low double-digit royalties for vaccines for pandemic preparedness and against seasonal influenza as well as three other infectious disease pathogens.

In evaluating the CSL Collaboration Agreement in accordance with ASC 606, the Company concluded that CSL Seqirus is a customer. The Company identified all promised goods/services within the CSL Collaboration Agreement, and when combining certain promised goods/services, the Company concluded that there are five distinct performance obligations. The nature of the performance obligations consists of the delivery of the vaccine license, research and development services for COVID-19 and non-COVID-19 vaccines and regulatory activities for COVID-19 vaccines. For each performance obligation, the Company estimated the standalone selling price based on 1) in the case of the license, the fair value using costs to recreate plus margin method and 2) in the case of research and development services and regulatory activities, cost plus margin for estimated full-time equivalent (“FTE”) costs, direct costs including laboratory supplies, contractors, and other out-of-pocket expenses for research and development services and regulatory activities.

As of December 31, 2025, the transaction price primarily consisted of upfront consideration received and milestones achieved. Additional variable consideration was not included in the transaction price at December 31, 2025 because the Company could not conclude that it is probable that including the variable consideration will not result in a significant revenue reversal.

The Company allocated the transaction price to the performance obligations in proportion to their standalone selling price. The vaccine license was recognized at the point in time it was transferred in 2022. The research and development and regulatory activities performance obligations are recognized over a period of time based on the percentage of services rendered using the input method, meaning actual costs incurred divided by total costs budgeted to satisfy the performance obligation. Any consideration related to sales-based royalties will be recognized when the amounts are probable of non-reversal, provided that the reported sales are reliably measurable and the Company has no remaining promised goods/services, as they are constrained and therefore have also been excluded from the transaction price. The revenue recognized during 2025 relates to the license delivered, milestones achieved and research and development and manufacturing services performed through December 31, 2025.

Total deferred revenue as of December 31, 2025 and 2024 for the CSL Collaboration Agreement was $6.2 million and $30.7 million, respectively.

During 2023, the Company entered into an amendment to the CSL Collaboration Agreement, pursuant to which the Company agreed to sponsor and conduct a Phase 1 clinical study in the influenza field. As part of the amendment, the Company received $17.5 million from CSL Seqirus. The amendment also provides for up to $1.5 million in additional payments which are achievable upon meeting certain clinical milestones relating to the Phase 1 clinical study in the influenza field. The Company previously concluded that the expansion of research and development support services under the CSL Collaboration Agreement represented an option that was not a material right. Therefore, the Company concluded the promise to sponsor and conduct the Phase 1 clinical study is a separate contract and the sole performance obligation under the new arrangement. During the period ended December 31, 2025, the Company recognized $3.2 million related to the performance obligation, which was fully satisfied during the period.

In March 2024, the Company entered into an amendment to the CSL Collaboration Agreement, pursuant to which the parties agreed to, among other things, adjust (i) the development plans for certain product candidates, (ii) various development milestones related to such product candidates, and (iii) provisions of the CSL Collaboration related to distributors, and (iv) proprietary payment calculations related to the foregoing.

BARDA Grant

In August 2022, the Company entered into a cost reimbursement contract (the “BARDA Contract”) with the Biomedical Advanced Research and Development Authority ("BARDA"), a division of the Office of the Assistant Secretary for Preparedness and Response (ASPR) within the U.S. Department of Health and Human

Services(HHS) for an award of up to $63.2 million for the development of a pandemic influenza vaccine using the Company's STARR® self-amplifying mRNA vaccine platform technology. The Company earns grant revenue for performing tasks under the agreement.

The Company determined that the BARDA Contract is not in the scope of ASC 808 or ASC 606. Applying International Accounting Standards No. 20 ("IAS 20"), Accounting for Government Grants and Disclosure of Government Assistance, by analogy, the Company recognizes grant revenue from the reimbursement of direct out-of-pocket expenses, overhead allocations and fringe benefits for research costs associated with the grant. The costs associated with these reimbursements are reflected as a component of research and development expense in the Company’s condensed consolidated statements of operations and comprehensive loss.

The Company recognized $13.2 million and $13.9 million of grant revenue during the years ended December 31, 2025 and 2024, respectively, which is included in revenue on the Company's consolidated statements of operations. As of December 31, 2025, the remaining available funding net of revenue earned was $26.7 million.

Gates Foundation

During the year ended December 31, 2025, the Company recognized $1.6 million of grant revenue related to cost reimbursement under two grants awarded by the Gates Foundation.

The grants support development of (i) a therapeutic HPV vaccine candidate and (ii) durability assessments of self-amplifying mRNA COVID-19 vaccine platforms. Grant funding is conditional upon achievement of defined milestones and submission of periodic progress and financial reports. Revenue is recognized as qualifying costs, including employee FTE labor and related expenses, are incurred in accordance with the terms of each agreement.

Unspent or uncommitted amounts remain deferred until the associated performance obligations are satisfied. As of December 31, 2025, deferred grant revenue related to these agreements totaled $2.1 million.

NOTE 4. Fair Value Measurements

The Company establishes the fair value of its assets and liabilities using the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. The Company established a fair value hierarchy based on the inputs used to measure fair value.

The three levels of the fair value hierarchy are as follows:

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

Level 2: Inputs, other than the quoted prices in active markets, that are observable either directly or indirectly.

Level 3: Unobservable inputs in which little or no market data exists and are therefore determined using estimates and assumptions developed by the Company, which reflect those that a market participant would use.

The Company's assets measured at fair value on a recurring basis consisted of money market funds. As of December 31, 2025, the Company's had money market funds with a fair value of $229.1 million, which were classified within Level 1 of the fair value hierarchy. The fair value of these financial instruments was measured based on quoted prices.

NOTE 5. Accrued Liabilities Detail

Accrued liabilities consisted of the following:

NOTE 6. Property and Equipment, Net

Property and equipment, net consisted of the following:

Depreciation and amortization expense was$3.0 million, $3.5 million and $3.0 million for the years ended December 31, 2025, 2024 and 2023, respectively. Construction in progress is primarily comprised of research equipment not yet placed in service.

NOTE 7. Debt

Wells Fargo Credit Agreement

The Company’s wholly-owned subsidiary, Arcturus Therapeutics, Inc. (“Arcturus Therapeutics”) entered into a credit agreement with Wells Fargo Bank on April 21, 2023, and amended on June 26, 2024, whereby Wells Fargo will make a $50.0 million revolving credit line available to the Company (the “Loan”) and each draw on the Loan evidenced by a revolving line of credit note (the “Note”). On June 26, 2024, the parties entered into Amendment No. 1 to the Wells Fargo Loan, whereby the term was extended byone year to April 2026.

Borrowings under the agreement will bear interest at a rate of 1.00% above either the Daily Simple SOFR or Term SOFR (as such terms are defined in the Note), with “SOFR” being the rate per annum equal to the secured overnight financing rate as administered by the Federal Reserve Bank of New York. If an Event of Default (as defined in the agreement) occurs, then all Loans shall bear interest at a rate equal to 2.00% above the interest rate applicable immediately prior to the occurrence of the Event of Default.

The term of the agreement was originallytwo years, with an option forone-year renewals subject to Wells Fargo approval and Arcturus Therapeutics furnishing to Wells Fargo a non-refundable commitment fee equal to 0.25% of the Loan amount for each such renewal. There is no penalty for terminating the facility prior to thematurity date of the Note. As collateral, the Company has agreed to pledge $55.0 million in cash to be held in the Company’s securities accounts with Wells Fargo Securities, LLC, an affiliate of Wells Fargo, pursuant to a security agreement.

In December 2025, the Company terminated the credit agreement and related security agreement. No amounts were outstanding under the Loan at the time of termination. As a result, $55.0 million of cash previously pledged as collateral was released and is no longer classified as restricted cash as of December 31, 2025.

NOTE 8. Stockholders’ Equity

Net Loss Per Share

Potentially dilutive securities that were not included in the calculation of diluted net loss per share for the year ended December 31, 2025 and 2024 as they were anti-dilutive totaled 0.6 million and 1.4 million, respectively. Potentially dilutive securities that were not included in the calculation of diluted earnings per share for the year ended December 31, 2023 as they were anti-dilutive totaled 0.8 million.

Sales Agreement

On December 23, 2022, the Company entered into a Controlled Equity Offering℠ Sales Agreement, which was amended on August 7, 2023 (as amended, the “Sales Agreement”) with Cantor Fitzgerald & Co. (“Cantor”),Wells Fargo Securities, LLC (“Wells Fargo Securities”), and William Blair & Company, L.L.C. (“William Blair”) relating to shares of the Company's common stock. In accordance with the terms of the Sales Agreement, the Company may offer and sell shares of its common stock having an aggregate offering price of up to $200 million from time to time through Cantor, Wells Fargo Securities, or William Blair, each acting as the Company's sales agent.

During the three months ended December 31, 2025, the Company sold 1,179,201 shares of its common stock pursuant to the Sales Agreement at a weighted‑average price of $10.38 per share, resulting in gross proceeds of approximately $12.2 million. After deducting offering costs of $0.5 million, the Company received net proceeds of approximately $11.7 million from these sales. In December 2025, the Company filed, and subsequently had declared effective, a replacement shelf registration statement on Form S‑3, which replaced the prior registration statement and continues to support the Sales Agreement.

NOTE 9. Share-Based Compensation

In June 2024 at the Company’s 2024 Annual Meeting of Stockholders (the "2024 Annual Meeting"), the stockholders of the Company approved an amendment to the Company’s 2019 Omnibus Equity Incentive Plan (as amended, the “2019 Plan”) which, among other things, increased the aggregate number of shares authorized for use in making awards to eligible persons under the 2019 Plan by 2,000,000 shares, for a total of up to 10,750,000 shares available for issuance. As of December 31, 2025, a total of 903,396 shares remain available for future issuance under the 2019 Plan, subject to the terms of the 2019 Plan.

In October 2021, the Company adopted the 2021 Inducement Equity Incentive Plan which covers the award of up to 1,000,000 shares of common stock (the “2021 Plan”) effective as of October 15, 2021. Approval of the Company’s stockholders is not required as a condition to the effectiveness of the 2021 Plan for so long as the plan is in compliance with applicable Nasdaq inducement plan rules. In April 2022, the compensation committee of the Company’s board of directors approved a proposal to reduce the total number of shares available for future issuance under the 2021 Plan to 130,000. Pursuant to the terms of the plan, shares underlying awards that are forfeited, cancelled, or terminated without issuance are returned to the share reserve. As of December 31, 2025, a total of 162,164 shares remain available for future issuance under the 2021 Plan, subject to the terms of the 2021 Plan.

Share Options

The following table presents the weighted-average assumptions used in the Black-Scholes valuation model by the Company in calculating the fair value of stock options granted:

The following table summarizes the Company’s stock option activity for the year ended December 31,2025:

At December 31, 2025, the total unrecognized compensation cost of $30.1 million will be recognized over the weighted-average remaining service period of approximately 2.5 years. The fair value of the options vested during the years ended December 31,2025 , 2024 and 2023 was $29.3 million, $40.5 million and $35.3 million, respectively. The total intrinsic value of options exercised during the years ended December 31,2025, 2024 and 2023 was $0.5 million, $3.3 million and $4.3 million, respectively.

Restricted Stock Units

In August 2023, the Company granted 18,786 restricted stock units (“RSUs”) to its board of directors, when the market value of the Company's common stock was $34.92 per share. These RSUs fully vested at the Company's 2024 annual stockholders' meeting. However, the release of the units remains subject to specific conditions and will occur only in the event of a board separation or a change in control.

The following table summarizes the Company’s RSU activity for the year ended December 31,2025:

Share-based compensation expenses included in the Company’s statements of operations and comprehensive income loss for the years ended December 31,2025, 2024 and 2023 were:

NOTE 10. Income Taxes

A reconciliation of (loss) income before income taxes for domestic and foreign locations is as follows:

A reconciliation of income tax (benefit) expense for the years ended December 31, 2025, 2024 and 2023 is as follows:

The table below provides the updated requirements of ASU No. 2023-09, Improvements to Income Tax Disclosures (“ASU 2023-09”) for 2025. The effective income tax rate for the years ended December 31, 2025 differs from the statutory federal income tax rate as follows (in thousands, except percentages):

(1) State tax expense in the State of California comprises the majority (greater than 50 percent) of the tax effect in this category.

As previously disclosed for the years ended December 31, 2024 and 2023, prior to the adoption of ASU 2023‑09, the Company’s effective income tax rate differed from the statutory federal income tax rate as follows:

A summary of income taxes paid, net of (refunds) received, for the year ended December 31, 2025 is as follows:

The significant components of deferred income taxes are as follows:

In assessing the realization of thedeferred tax assets, the Company considers whether it is more likely than not that some portion of the deferred tax assets will not be realized. The ultimate realization of deferred tax assets is dependent upon the generation of future taxable income during the periods in which temporary differences representing net future deductible amounts become deductible. Due to lack of available sources of taxable income, the Company recorded a full valuation allowance against its net deferred tax assets as sufficient uncertainty exists regarding the future realization of these assets. As of December 31, 2025 and 2024, the Company recorded a valuation allowance of $143.5 million and $138.0 million, respectively. The valuation allowance changed by $5.5 million and $29.2 million for the years ended December 31, 2025 and 2024, respectively.

Pursuant to Internal Revenue Code (IRC) Sections 382 and 383, annual use of the Company’s federal and state net operating loss, research and development credit carryforwards, and other tax attributes may be limited in the event a cumulative change in ownership of more than 50% occurs within athree-year period. The Company has experienced changes in prior years and there is a risk that additional ownership changes may occur in the future. If a change in ownership occurs, the NOL carryforwards and other tax attributes could be limited or restricted. At December 31, 2025, the Company has federal and state net operating losses, or NOL, carryforwards of approximately $115.5 million and $203.1 million, respectively. The federal net operating loss carryforward includes losses generated in 2018 and after, which can be carried forward indefinitely. The state net operating loss carryforward includes $0.7 million of losses that can be carried forward indefinitely. The remaining state net operating losses begin to expire in 2039.

At December 31, 2025, the Company has federal and state research and development credit carryforwards of approximately $18.1 million and $12.5 million, respectively. If not utilized, the federal credit carryforwards begin to expire in 2037. $1.0 million of the state credit begins to expire in 2037 and the remainder carries forward indefinitely. Additionally, the Company has an Orphan Drug Credit of $8.9 million as of December 31, 2025, which will begin to expire in 2042 unless previously utilized.

The company accounts for income taxes in accordance with ASC 740-10, Accounting for Uncertainty in Income Taxes. The impact of an uncertain income tax position on the income tax return must be recognized at the largest amount that is more likely than not to be sustained upon audit by the relevant taxing authority. An uncertain tax position will not be recognized if it has less than 50% likelihood of being sustained.

A reconciliation of unrecognized tax benefits is as follows (in thousands):

Amounts in the summary rollforward would not impact our effective tax rate if recognized as the Company maintains a full valuation on its net deferred tax assets. The Company is subject to taxation and files income tax returns in the United States, various U.S. states and foreign jurisdictions. The Company’s tax years from 2014 to date are subject to examination by the U.S., and state taxing authorities due to the carryforward of unutilized net operating losses and research and development credits. The general statute of limitations in the foreign jurisdictions where the Company files tax returns is 4 to 5 years. The Company’s policy is to recognize interest expense and penalties related to income tax matters as income tax expense. There wasno tax related interest or penalties recognized for the years ended December 31, 2025 and 2024 and 2023.

Deferred income taxes are not required for undistributed earnings of the Company’s foreign subsidiary as they can be distributed tax free and without withholding taxes.

On July 4, 2025, the One Big Beautiful Bill Act (the "Act") was signed into law. The Act reinstates and makes permanent 100% first-year bonus depreciation under Section 168(k) for qualified property acquired and placed in service after January 19, 2025. Additionally, the Act permanently allows immediate expensing of domestic research and experimentation expenditures under Section 174 for tax years beginning after December 31, 2024. The Company has reflected the effects of the Act in its income tax provision in accordance with ASC 740.

NOTE 11. Commitments and Contingencies

Cystic Fibrosis Foundation Therapeutics Funding agreement

On September 25, 2023, the Company amended its Development Program Letter Agreement, dated May 16, 2017 and as amended July 13, 2018 and August 1, 2019, with the Cystic Fibrosis Foundation (“CFF”). Pursuant to the amendment, (i) CFF increased the amount it will award to advance LUNAR-CF to $24.6 million from approximately $15.6 million, and (ii) the Company agreed to incur at least $15.0 million toward activities under the research plan. During the fourth quarter of 2023, the Company received the full payment from CFF related to the amendment. For the years ended December 31, 2025, 2024 and 2023, the Company recognized contra expense of $1.0 million, $0.2 million and $1.4 million, respectively. As of December 31, 2025, $6.4 million remained in accrued liabilities.

Leases

In October 2017, the Company entered into a non-cancellable operating lease agreement for office space adjacent to its previously occupied headquarters. The commencement of the lease began in March 2018 and the lease extends for approximately 84 months from the commencement date with a remaining lease term through March 2025. Monthly rental payments are due under the lease and there are escalating rent payments during the term of the lease. The Company is also responsible for its proportional share of operating expenses of the building and common areas. In conjunction with the new lease, the Company received free rent forfour months and received a tenant improvement allowance of $0.1 million. The Company entered into an irrevocable standby letter of credit with the landlord for a security deposit of $0.1 million upon executing the lease which is included (along with additional funds required to secure the letter of credit) in the balance of non-current restricted cash. In March 2024, the Company negotiated with the lessor to extend the lease through March 2027.

In December 2025, the Company vacated this office space with no intention of operating out of the location in the future. The Company remains obligated to make the remaining lease payments through March 2027, and therefore recorded an impairment loss in the amount of $1.9 million during the three months ended December 31, 2025, as there was no future economic benefit from the lease.

In February 2020, the Company entered into a second non-cancellable operating lease agreement for office space near its current headquarters. The lease extended for 13 months from the commencement date and included a right to extend the lease for one twelve-month period. In February 2021, the Company opted to extend the lease through March 2025 to coincide with the lease term of the Company’s headquarters. In January 2024, the Company vacated this office space with no intention of operating out of the location in the future. The Company was still engaged in the lease for the property and obligated to make the remaining lease payments through March 2025, and therefore recorded an impairment loss in the amount of $1.3 million during the three months ended March 31, 2024, as there was no future economic benefit from the lease. In July 2024, the Company terminated the existing lease agreement, in accordance with its terms, thereby ending their contractual obligation to pay for the premises.

In September 2021, the Company entered into a third non-cancellable lease agreement for office, research and development, engineering and laboratory space near its current headquarters, and such lease term commenced during the second quarter of 2022. The initial term of this lease extendsten years and eight months from the date of possession, andthe Company has the right to extend the term of the lease for an additional five-year period. When the lease term was determined for the operating lease right-of-use assets and lease liabilities, the extension option for the lease was not included. The lease has a monthly base rent ranging from $0.3 million to $0.4 million which escalates over the lease term. The Company received a free rent period of four months and also pays for various operating costs, including utilities and real property taxes. The Company entered into an irrevocable standby letter of credit with the landlord for a security deposit of $2.0 million upon executing the lease which is included (along with additional funds required to secure the letter of credit) in the balance of non-current restricted cash.

Operating lease right-of-use asset and liability on the consolidated balance sheets represent the present value of remaining lease payments over the remaining lease terms. The Company does not allocate lease payments to non-lease components; therefore, payments for common-area-maintenance and administrative services are not included in the operating lease right-of-use asset and liability. The Company uses its incremental borrowing rate to calculate the present value of the lease payments, as the implicit rate in the lease is not readily determinable.

As of December 31,2025, the remaining payments of the operating lease liability were as follows:

Operating lease costs consist of the fixed lease payments included in operating lease liability and are recorded on a straight-line basis over the lease terms. Operating lease costs were $5.0 million, $4.5 million and $5.6 million for the years ended December 31,2025, 2024 and 2023, respectively.

NOTE 12. Segment Information

The Company operates inone business segment, which includes all activities related to the discovery, development and commercialization of messenger RNA medicines. The determination of a single business segment is consistent with the consolidated financial information regularly provided to the Company’s chief operating decision maker (“CODM”). The Company’s CODM is its Chief Executive Officer, who reviews and evaluates consolidated net loss for purposes of assessing performance, making operating decisions, allocating resources, and planning and forecasting for future periods. The CODM does not evaluate the operating segment using asset or liability information.

The following table presents information about reported segment revenues, segment loss, and significant segment expenses:

(1)Primarily includes interest income and expense, foreign currency gains and losses, and income taxes. The year ended December 31, 2023 includes a $34.0 million gain on debt extinguishment related to forgiveness of the Singapore Loan.

NOTE 13. Related Party Transactions

See “Note 2, Joint Ventures, Equity Method Investments and Variable Interest Entities” for specific details surrounding the Company’s agreement with Axcelead to form the joint venture entity, ARCALIS, Inc.

NOTE 14. Subsequent Events

None.