v3.26.1
Stockholders' Equity
 6 Months Ended
Jun. 30, 2026
Equity [Abstract]  
Stockholders' Equity Stockholders’ Equity
Preferred Stock
The Company has 50,000,000 shares of preferred stock authorized. The Company has designated a Series A Preferred Stock, a Series B Preferred Stock, and a Series C Preferred Stock.
Series A Preferred Stock
The Company has designated 10,000,000 shares of Series A Preferred Stock, par value of $0.0001. As of June 30, 2026 and December 31, 2025, the Company has 5,875,000 shares of Series A Preferred Stock issued and outstanding, which is convertible into 587,500 shares of the Company's common stock.
For the six months ended June 30, 2026 and 2025, the Company recognized $36,539 and $36,539, respectively, in Series A dividends, all of which have been paid as of June 30, 2026.
Series B Preferred Stock
The Company has designated 10,000,000 shares of Series B Preferred Stock, par value of $0.0001. As of June 30, 2026 and December 31, 2025, the Company has 0 shares of Series B Preferred Stock issued and outstanding.
Series C Preferred Stock
The Company has designated 10,000,000 shares of Series C Preferred Stock, par value of $0.0001. As of June 30, 2026, the Company has 570,000 shares of Series C Preferred Stock issued and outstanding, which is convertible into 356,250 shares of the Company's common stock. As of December 31, 2025, the Company had 570,000 shares of Series C Preferred Stock issued and outstanding.
For the six months ended June 30, 2026 and 2025, the Company recognized $17,100 and $17,265 in Series C dividends, all of which have been paid as of June 30, 2026.
Common Stock
The Company has 3,000,000,000 shares of common stock, par value $0.0001 authorized. The Company has 94,698,939 and 94,612,750 shares issued and outstanding as of June 30, 2026, and December 31, 2025, respectively.
On September 17, 2025, the Company filed a registration statement on Form S-8 (File No. 333-290331) to register an aggregate of 3,000,000 shares of the Company's common stock to be issued pursuant to the Castellum, Inc. 2025 Employee Stock Purchase Plan ("ESPP"). The ESPP was adopted by the Company’s Board of Directors on March 11, 2025 and approved by the Company’s stockholders at the annual meeting held on May 28, 2025. The ESPP is a voluntary employee benefit program that permits eligible employees to contribute up to 5% of their eligible compensation through payroll deductions each pay period. Payroll deductions and purchases of Company common stock under the ESPP did not commence until 2026. Shares are purchased on behalf of participating employees on a quarterly basis at a price equal to 85% of the fair market value on the applicable purchase date. The ESPP is intended to provide employees with an opportunity to acquire an ownership interest in the Company and is not a component of executive compensation. During the six months ended June 30, 2026, 86,189 shares of common stock were issued.

On June 1, 2026, the Company filed a registration statement on Form S-8 (File No.333-296389) to register an additional 4,000,000 shares of common stock for issuance under the Castellum, Inc. Third Amended 2021 Stock Incentive Plan. Following this filing, a total of 13,000,000 shares of common stock are registered and available for issuance under the plan.
Warrants
As of June 30, 2026, the Company had 5,653,981 warrants outstanding and exercisable, which were granted to officers, directors, and an investor of the Company between 2019 and 2023 and remain outstanding under their original terms. There was no warrant issuance, exercise, expiration, or cancellation activity during the six months ended June 30, 2026.

Separately, in 2024 the Company issued warrants in a private transaction, all of which were fully exercised in 2025. The Company also issued warrants in connection with registered offerings completed in the first half of 2025, all of which were either exercised or expired prior to December 31, 2025. No warrants from either of these transactions remained outstanding as of December 31, 2025. See Note 11 to the Company's Annual Report on Form 10-K for the year ended December 31, 2025, for additional information regarding these warrants.

The following table represents a summary of warrants for the six months ended June 30, 2026 and the year ended December 31, 2025:
Six Months Ended
June 30, 2026		Year Ended
December 31, 2025
NumberWeighted
Average
Exercise
Price		NumberWeighted
Average
Exercise
Price
Beginning balance5,653,981$1.40 8,744,698$1.40 
Granted— — 8,666,6670.34 
Exercised— — (8,509,926)0.41 
Expired— — (3,247,458)1.08 
Ending balance5,653,981$2.05 5,653,981$1.40 
Warrants exercisable 5,653,9815,653,981
Intrinsic value of warrants$— $— 
Weighted Average Remaining Contractual Life (Years)2.623.12
Options
On November 9, 2021, the Company approved the 2021 Stock Incentive Plan ("Stock Incentive Plan") that authorized the Company to issue up to 2,500,000 shares of common stock. Prior to this date, the granting of options was not done pursuant to the terms of a stock incentive plan. On November 9, 2023 the Board approved an amendment to the Stock Incentive Plan to increase the aggregate number of shares available for issuance from 2,500,000 to 6,000,000 (the "Amended Plan"), which was approved by the Company's shareholders at its annual meeting on May 29, 2024.
On March 11, 2025, the Board approved an amendment to the Amended Plan to further increase the aggregate number of shares available for issuance from 6,000,000 to 9,000,000 (the "Second Plan Amendment" and the "Second Amended Plan"), which was approved by the Company's stockholders at the Company's 2025 annual meeting of stockholders held on May 28, 2025. On March 6, 2026 the Board approved an additional amendment to the Second Amended Plan to increase the aggregate number of shares available for issuance by 4,000,000 shares (the "Third Plan Amendment" and the "Third Amended Plan"), resulting in an aggregate of 13,000,000 shares available for issuance under the Third Amended Plan, which was approved by the Company's stockholders at the Company's 2026 annual meeting of stockholders held on May 19, 2026. As of June 30, 2026, 8,212,500 stock options have been granted under the Third Amended Plan.
The following represents a summary of options granted under the terms of the Amended Plan and additional options granted outside of the Amended Plan, for the six months ended June 30, 2026 and the year ended December 31, 2025:
NumberWeighted
Average
Exercise
Price		Weighted-Average Remaining Contractual Term (in Years)Weighted
Average
Fair Value
Outstanding December 31, 202513,352,500 $1.81 4.67$2.64 
Granted—— 0— 
Exercised— — 0— 
Forfeited(290,000)1.49 01.42
Outstanding June 30, 202613,062,500$1.82 4.20$2.70 
As of June 30, 2026
Vested and exercisable9,218,563$1.93 3.79$2.23 
During the six months ended June 30, 2026, the Company recognized $1,524,320 of noncash stock-based compensation related to the vesting of service-based stock options and the discount on the ESPP. No options were exercised during the six months ended June 30, 2026.
The fair value of each option is estimated using the Black-Scholes valuation model. Changes to these inputs could produce a significantly higher or lower fair value measurement. The following assumptions were used for the year ended December 31, 2025, no options were granted during three months ended June 30, 2026:
Year Ended
December 31, 2025
Expected term7 years
Expected volatility
123.05% – 124.33%
Expected dividend yield— 
Risk-free interest rate
3.90% - 4.14%