SIGA TECHNOLOGIES INC

3. Procurement Contracts and Research Agreements

19C BARDA Contract

On* September 10, 2018,the Company entered into a contract with the U.S. Biomedical Advanced Research and Development Authority ("BARDA") pursuant to which SIGA agreed to deliver up to 1,488,000 courses of oral TPOXX® to the U.S. Strategic National Stockpile ("Strategic Stockpile"), and to manufacture and deliver to the Strategic Stockpile, or store as vendor-managed inventory, up to 212,000 courses of IV TPOXX®. In October 2023,the contract was modified so that a course of IV TPOXX® was redefined within the contract from being 14 vials to being 28 vials; as such, the19C* BARDA Contract currently specifies 106,000 courses of IV TPOXX® (for the same payment amount as originally specified). In addition to the delivery of TPOXX® courses, the contract includes funding from BARDA for a range of activities, including: advanced development of IV TPOXX®, post-marketing activities for oral and IV TPOXX®, development of a pediatric formulation, support for manufacturing activities, and procurement activities. On* April 8, 2025,total payments contemplated under the contract with BARDA were increased by $14.3 million to add funding for activities supporting manufacturing. On June 3, 2025,total payments contemplated under the contract with BARDA were increased by $13.2 million in connection with the development of the pediatric formulation of TPOXX®. On August 7, 2026,total payments contemplated under the contract with BARDA were increased by $2.1 million to add funding for regulatory activities supporting oral TPOXX®. As of September 30, 2026*, the contract with BARDA (as amended, modified, or supplemented from time to time, the*"19C* BARDA Contract") contemplates up to approximately $632.1 million of payments, of which approximately $81.3 million of payments are included within the base period of performance, approximately $545.2 million of payments are related to exercised options, and up to approximately $5.6 million of payments are currently specified as unexercised options. BARDA* maychoose in its sole discretion when, or whether, to exercise any of the unexercised options. The period of performance for options is up toten years from the date of entry into the19C* BARDA Contract and such options could be exercised at any time during the contract term.

The base period of performance specifies potential payments of approximately $81.3 million for the following activities: payments of approximately $11.1 million for the delivery of approximately 35,700 courses of oral TPOXX® to the Strategic Stockpile; payments of $8.0 million for the manufacture of 10,000 courses (as currently defined within the contract as being28 vials) of final drug product of IV TPOXX® ("IV FDP"), of which $3.2 million of payments are related to the manufacture of bulk drug substance ("IV BDS") to be used in the manufacture of IV FDP; payments of approximately $61.6 million to fund reimbursed activities; and payments of approximately $0.6 million for supportive procurement activities. As of* September 30, 2026*, the Company had received $11.1 million for the delivery of approximately 35,700 courses of oral TPOXX® to the Strategic Stockpile, $3.2 million for the manufacture of IV BDS, $4.8 million for the delivery of IV FDP to the Strategic Stockpile and $38.6 million for other base period activities. IV BDS has been used for the manufacture of courses of IV FDP.

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The options that have been exercised as of* September 30, 2026*, provide for payments up to approximately $545.2 million. As of* September 30, 2026*, there are exercised options for the following activities: payments up to $450.2 million for the manufacture and delivery of up to 1.5 million courses of oral TPOXX®; payments up to $76.8 million for the manufacture of courses of IV FDP; payments of up to approximately $3.6 million to fund post-marketing activities for IV TPOXX®; and payments of up to $14.6 million for funding of post-marketing activities for oral TPOXX®. As of* September 30, 2026*, a cumulative total of $450.2 millionof oral TPOXX® has been delivered to the Strategic Stockpile and accepted; a cumulative total of $76.8 million of IV FDPhas been delivered to the Strategic Stockpile and accepted (IV BDS that had been set aside and recorded as deferred revenue was recognized as revenue when the IV FDP, containing IV BDS, was delivered); and the Company has been cumulatively reimbursed $13.9 million in connection with post-marketing activities for oral and IV TPOXX®.

Unexercised options specify potential payments up to approximately $5.6 million in total (if all such options are exercised), all of which relates to supportive activities that we currently donot expect to be required.

The options related to IV TPOXX® were divided intotwo primary manufacturing steps. There were options related to the manufacture of bulk drug substance (“IV BDS Options”), and there were corresponding options (for the same number of IV courses) for the manufacture of final drug product (“IV FDP Options”). BARDA had the sole discretion to choose to exercise any, all, ornone of these options. The19C BARDA Contract included: three separate IV BDS Options, each providing for the bulk drug substance equivalent of 32,000 courses (as currently defined within the contract) of IV TPOXX®; andthree separate IV FDP Options, each providing for 32,000 courses of final drug product of IV TPOXX®. BARDA had the sole discretion as to whether to simultaneously exercise IV BDS Options and IV FDP Options, or whether to exercise options at different points in time (or alternatively, to only exercise the IV BDS Option butnot the IV FDP Option). To date, BARDA has exercised allthree IV BDS options and allthree IV FDP options.

Revenues in connection with the19C BARDA Contract are recognized either over time or at a point in time. Performance obligations related to product delivery generate revenue at a point in time. Revenue from other performance obligations under the19C BARDA Contract is recognized over time using an input method based on costs incurred to date relative to total estimated costs at completion. For thethree months ended* September 30, 2026and2025*, the Company recognized revenues of $1.3 million and $2.6 million, respectively, on an over time basis. For thenine months ended* September 30, 2026and2025*, the Company recognized revenues of $10.0 million and $5.8 million, respectively, on an over time basis. In contrast, revenue recognized for product delivery, and therefore at a point in time, for thenine months ended* September 30, 2026and2025* was $25.6 million and $79.1 million, respectively. There wasno revenue recognized for product delivery, and therefore at a point in time, for thethree months ended* September 30, 2026* and2025.

International Sales Activity

Revenue in connection with international procurement contracts for the delivery of product are recognized at a point in time on a gross basis, as the Company acts as the principal in the transaction. During thenine months ended* September 30, 2026*, the Company has recognized $13 million of international sales. During thenine months ended* September 30, 2025*, the Company recognized $5.8 million of sales in connection with international contracts. There wasno revenue recognized in connection with international contracts during thethree months ended* September 30, 2026or September**30,* 2025, respectively.

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International Commercial Agreements

Canada Sales Agreement

On* October 28, 2026,the Company announced that the Canadian Department of National Defence (the "CDND") awarded it a contract (the "Canadian DND Contract"), pursuant to which the CDND will purchase treatment courses of oral TPOXX® overfive* years for a total value of up to approximately $15 million by* March 31, 2031,of which approximately $9 million represents firm commitments over thefirst* three years of the contract and approximately $6 million is subject to option exercise by the CDND.

MENA License Agreement

In* March 2026,*the Company entered into an exclusive license and distribution agreement with Hikma MENA FZE (“Hikma”) that gives Hikma the right to register and commercialize oral TPOXX® in the Middle East and North Africa (MENA) region. Under the terms of the agreement, the Company will be the sole manufacturer of tecovirimat and will supply finished product to Hikma.

Meridian Agreement*** ***

The International Promotion Agreement with Meridian expired on* May 31, 2026.Under the terms of the International Promotion Agreement, which was amended on March 27, 2024,and effective June 1, 2024,and further amended on August 30, 2024,the Company had primary responsibility for the advertising, promotion and sale of oral TPOXX® in all geographic regions. Meridian had limited, non-exclusive rights to advertise, promote, offer for sale and sell oral TPOXX® in the European Economic Area, Australia, Japan, Switzerland, the United Kingdom and the Association of Southeast Asian Nations and its member states (collectively, the “Current Territory”). Meridian also performed non-promotional activities under specified contracts withthird* parties entered into prior to* June 1, 2024,*that provided for the sale of oral TPOXX® in the Current Territory. The International Promotion Agreement entitled Meridian to receive a fee equal to a high single digit percentage of collected proceeds (whether collected by Meridian or the Company), net of certain expenses, of sales of oral TPOXX® in the Current Territory in the field of use specified in the International Promotion Agreement.

Under the terms of the original International Promotion Agreement (“Pre-amendment International Promotion Agreement”), which had an initial term that expired on* May 31, 2024,Meridian had been granted exclusive rights to market, advertise, promote, offer for sale, or sell oral TPOXX® in a field of use specified in the International Promotion Agreement in all geographic regions except for the United States (the “Territory”), and Meridian agreednot* to commercialize any competing product, as defined in the Pre-amendment International Promotion Agreement, in the specified field of use in the Territory. Under the Pre-amendment International Promotion Agreement, as well as the current International Promotion Agreement, SIGA has always retained ownership, intellectual property, distribution and supply rights and regulatory responsibilities in connection with TPOXX®, and, in the United States market, also retained sales and marketing rights with respect to oral TPOXX®. SIGA’s consent is required prior to the entry by Meridian into any sales arrangement pursuant to the International Promotion Agreement.

Sales to international customers pursuant to the Pre-amendment International Promotion Agreement were invoiced and collected by Meridian, and such collections were remitted, less Meridian’s fees, to the Company under a quarterly process specified in the Pre-amendment International Promotion Agreement; and Meridian was entitled to a specified percentage of the collected proceeds of sales of oral TPOXX®, net of certain expenses, for calendar years in which customer collected amounts net of such expenses were less than or equal to a specified threshold, and to a higher specified percentage of such collected net proceeds for calendar years in which such net collected amounts exceeded the specified threshold. Subsequent to* June 1, 2024,only specified procurement contracts for the Current Territory entered into prior to June 1, 2024,*continue to involve Meridian invoicing and collecting proceeds, and retaining a fee pursuant to the International Promotion Agreement.

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4. Inventory

Inventory includes costs related to the manufacture of TPOXX®. Inventory consisted of the following:

During thenine months ended* September**30,* 2026, the Company recognized a recovery of approximately $0.7 million from a contract manufacturing organization associated with a previous loss of inventory. During thenine months ended* September 30, 2025*, the Company wrote off approximately $0.9 million of inventory. In addition, during thenine months ended* September 30, 2025*, the Company recognized a recovery of approximately $0.5 million from a contract manufacturing organization associated with a previous loss of inventory.

5. Property, Plant and Equipment

Property, plant and equipment consisted of the following:

Depreciation and amortization expense on property, plant, and equipment was $0.5 million and $0.4 million for thenine months ended* September 30, 2026and2025*, respectively.

6. Accrued Expenses and Other Current Liabilities

Accrued expenses and other current liabilities consisted of the following:

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7. Fair Value of Financial Instruments

The carrying value of cash and cash equivalents, accounts receivable, accounts payable, accrued expenses and other current liabilities, and income tax payable approximates fair value due to the relatively short maturity of these instruments.

The measurement of fair value requires the use of techniques based on observable and unobservable inputs. Observable inputs reflect market data obtained from independent sources, while unobservable inputs reflect our market assumptions. The inputs create the following fair value hierarchy:

There wereno transfers between levels of the fair value hierarchy for thenine months ended* September 30, 2026*. As of* September 30, 2026* and* December 31, 2025*, the Company had $57.3 million and $55.8 million, respectively, of cash equivalents classified as Level1 financial instruments. There wereno Level2 or Level3 financial instruments as of* September 30, 2026* or* December 31, 2025*.

8. Per Share Data

The Company computes, presents and discloses earnings per share in accordance with the authoritative guidance, which specifies the computation, presentation and disclosure requirements for earnings per share of entities with publicly held common stock or potential common stock. The objective of basic EPS is to measure the performance of an entity over the reporting period by dividing income by the weighted average shares outstanding. The objective of diluted EPS is consistent with that of basic EPS, except that it also gives effect to all potentially dilutive common shares outstanding during the period.

The following is a reconciliation of the basic and diluted earnings per share computation:

For thenine months ended* September 30, 2026* and* September 30, 2025,respectively, weighted-average diluted shares include the dilutive effect of in-the-money options and stock settled RSUs. The dilutive effect of stock-settled RSUs and options is calculated based on the average share price for each fiscal period using the treasury stock method. Under the treasury stock method, the amount the employee must pay for exercising stock options, the average amount of compensation cost for future service that the Company hasnot* yet recognized, and the amount of tax benefits that would be recorded in additional paid-in capital when the award becomes deductible, are collectively assumed to be used to repurchase shares. Cash-settled RSUs were presumed to be cash-settled and therefore excluded from the diluted earnings per share calculations for thenine months ended* September 30, 2026* and* September 30, 2025,respectively, because the net effect of their inclusion, including the elimination of the impact in the operating results of the change in fair value of these RSUs, would have been anti-dilutive. Performance-based RSUs were excluded from the diluted earnings per share calculations for thenine* months ended* September 30, 2026* and* September 30, 2025,respectively, as a result of the associated metrics/contingenciesnot* being achieved. For thenine months ended* September 30, 2026* and* September 30, 2025,respectively, the weighted average number of shares under the cash-settled RSUs excluded from the calculation of diluted earnings per share was 59,384 and 44,411 for the2026* and2025 periods, respectively.

For thethree months ended* September 30, 2026and September 30, 2025,*respectively, the Company incurred a loss and as a result, the equity instruments listed below were excluded from the calculation of diluted loss per share as the effect of the exercise, conversion or vesting of such instruments would have been anti-dilutive. The weighted average number of equity instruments excluded consists of:

(1) For thethree months ended* September 30, 2026and2025,* the total excludes a weighted average of 71,757 and 50,645 cash-settled RSUs, respectively.

(2) Performance-based RSUs were excluded as a result of the associated metrics/contingenciesnot being achieved.

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9. Commitments and Contingencies

From time to time, we* maybe involved in a variety of claims, suits, investigations and proceedings arising from the ordinary course of our business, collections claims, breach of contract claims, labor and employment claims, tax and other matters. Although such claims, suits, investigations and proceedings are inherently uncertain and their results cannot be predicted with certainty, we believe that the resolution of such current pending matters, if any, willnot* have a material adverse effect on our business, consolidated financial position, results of operations or cash flow. Regardless of the outcome, litigation can have an adverse impact on us because of legal costs, diversion of management resources and other factors.

Purchase Commitments

In the course of our business, the Company regularly enters into agreements withthird party organizations to provide contract manufacturing services and research and development services. Under these agreements, the Company issues purchase orders, which obligate the Company to pay a specified price when agreed-upon services are performed. In connection with many CMO purchase orders, reimbursement by CMOs for inventory losses is limited. Commitments under the purchase orders donot exceed our planned commercial and research and development needs. As of* September 30, 2026*, the Company had approximately $0.5 million of purchase commitments associated with manufacturing obligations.

10. Related Party Transactions

Real Estate Leases

On* May 26, 2017,the Company and MacAndrews & Forbes Incorporated ("M&F") entered into aten*-year Office Lease agreement (the "New HQ Lease"), pursuant to which the Company agreed to lease 3,200 square feet at31 East62nd Street, New York, New York. The Company is utilizing premises leased under the New HQ Lease as its corporate headquarters. The Company's rental obligations consisted of a fixed rent of $25,333 per month in thefirst sixty-three months of the term, subject to a rent abatement for thefirst six months of the term. From thefirst day of thesixty-fourth month of the term through the expiration or earlier termination of the lease, the Company's rental obligations consist of a fixed rent of $29,333 per month. In addition to the fixed rent, the Company will pay a facility fee in consideration of the landlord making available certain ancillary services, commencing on thefirst anniversary of entry into the lease. The facility fee was $3,333 per month for thesecond year of the term and increases byfive percent each year thereafter, to $4,925 per month in the final year of the term. During thethree andnine months ended* September 30, 2026*, the Company paid $0.1 million and $0.3 million, respectively, for rent and ancillary services associated with this lease. The Company hadno outstanding payables or accrued expenses related to this lease as of* September 30, 2026*.

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11. Segment and Geographic Information

The Company operates inone single operating and reportable segment, which includes all activities related to the sale of the Company’s oral and IV TPOXX® as well as research and development services. The Company derives revenue primarily from sales to the U.S. Government as well as international governments (including government affiliated entities) and manages the business activities on a consolidated basis. The segment derives revenues from customers through the delivery of product and fulfillment of research and development services.

The Chief Operating Decision Maker ("CODM") assesses performance for the segment and decides how to allocate resources based on net income that also is reported on the income statement as consolidated net income. Consolidated net income is also a measure that is considered in monitoring budget versus actual results.

The CODM doesnot review assets in evaluating the results of the segment, and therefore, such information isnot presented.

The following table provides the operating result of the Company's segment:

(1) Other segment items include insurance, business development costs, regulatory and consultant expenses, as well as various general corporate costs.

Revenues by geographic region were as follows:

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12. Income Taxes

The Company’s provision for income taxes consists of federal and state taxes, as applicable, in amounts necessary to align the Company’s year-to-date tax provision with the effective rate that it expects to achieve for the full year. Each quarter the Company updates its estimate of the annual effective tax rate and records cumulative adjustments as necessary.

For thethree months ended* September 30, 2026and2025*, we recorded pre-tax losses of $5.5 million and $8.4 million, respectively, and a corresponding income tax benefit of $2.6 million and $2.0 million, respectively.

For thenine months ended* September 30, 2026and2025*, we recorded pre-tax income of $5.3 million and $38.3 million, respectively, and a corresponding income tax benefit/(provision) of $0.8 million and ($9.6) million, respectively.

The effective tax rate for thethree months ended* September 30, 2026* was 47.2% compared to 23.8% for thethree months ended* September 30, 2025*. The effective tax rate for thethree months ended* September 30, 2026* differed from the U.S. statutory rate of 21% primarily as a result of currently forecasted losses for the full year, state taxes and various non-deductible expenses, including executive compensation under Internal Revenue Code Section162(m). With respect to currently forecasted losses for the full year, such forecast is based on orders received to date and is subject to update upon the receipt of new procurement orders.

The effective tax rate for thenine months ended* September 30, 2026* was (14.8%) compared to 25.1% for thenine months ended* September 30, 2025*. The effective tax rate for thenine months ended* September 30, 2026* differed from the U.S. statutory rate of 21% primarily as a result of currently forecasted losses for the full year, state taxes and various non-deductible expenses, including executive compensation under Internal Revenue Code Section162(m). With respect to currently forecasted losses for the full year, such forecast is based on orders received to date and is subject to update upon the receipt of new procurement orders.

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13. Equity

The tables below present changes in stockholders' equity for thethree andnine months ended* September 30, 2026* and2025.

On* March 26, 2026,the Board of Directors declared a special cash dividend of $0.60 per share on the common stock of the Company. The special cash dividend was paid on April 23, 2026 to shareholders of record at the close of business on April**7,* 2026.

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14. Leases

The Company leases its Corvallis, Oregon, office space under an operating lease, which was signed on* November 3, 2017and commenced on January 1, 2018.The initial term of this lease was to expire on December 31, 2019after which the Company hadtwo successive renewal options;one fortwo years and the other forthree years. In thesecond* quarter of2019, the Company exercised thefirst renewal option, which extended the lease expiration date to* December 31, 2021.In thesecond* quarter of2021, the Company exercised thesecond renewal option, which extended the lease expiration date to* December 31, 2024.In thesecond* quarter of2024, the Company entered into an additional addendum, which extended the lease expiration date to* December 31, 2026.In connection with this additional addendum, the Company recorded an increase to operating lease right-of-use assets and operating lease liabilities of approximately $0.5 million in thesecond* quarter of2024.

On* May 26, 2017,the Company and M&F entered into the New HQ Lease, aten-year office lease agreement, pursuant to which the Company agreed to lease 3,200 square feet in New York, New York. The Company is utilizing premises leased under the New HQ Lease as its corporate headquarters. The Company hasno* leases that qualify as finance leases.

Operating lease costs totaled $0.2 million for each of thethree months ended* September 30, 2026and2025*. Operating lease costs totaled $0.5 million for each of thenine months ended* September 30, 2026and2025*. Cash paid for amounts included in the measurement of lease liabilities from operating cash flows was $0.2 million for each of thethree months ended* September 30, 2026and2025*. Cash paid for amounts included in the measurement of lease liabilities from operating cash flows was $0.5 million for each of thenine months ended* September 30, 2026and2025*. As of* September 30, 2026*, the weighted-average remaining lease term of the Company’s operating leases was 0.55 years while the weighted-average discount rate was 9.95%.

Future cash flows under operating leases as of* September 30, 2026* are expected to be as follows:

As of* September 30, 2026*, the lease liability is included in accrued expenses and other current liabilities on the condensed consolidated balance sheet.

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15. Subsequent Event

On* November 4, 2026,the Company’s Chief Scientific Officer (“Officer”) informed the Company of his intent to retire as Executive Vice President and Chief Scientific Officer of the Company, effective November 9, 2026 (the “Retirement Date”). The Company and the Officer have entered into a retirement and consulting agreement (the “Retirement and Consulting Agreement”) pursuant to which the Officer will provide the Company consulting services from his Retirement Date through May 9, 2028.The Company expects to incur an aggregate charge of approximately $1.8 million in thefourth* quarter of2026 in connection with the retirement of the Officer, which includes the value of vesting equity and is expected to be paid over the nexttwo years. The charge doesnot include payments in connection with any consulting services under the Retirement and Consulting Agreement.