Castellum, Inc. (CTM) Institutional Ownership

Ownership Summary

Castellum, Inc. (NYSE:CTM) is held by 38 institutional investors per 13F filings through December 2025.

• Collectively, these holders controlled 11.4% of Castellum's outstanding shares in December 2025, up from 6.2% in September 2025.
• Their total shares held in CTM increased 90.79% quarter over quarter, and separately, investors owning Castellum increased 80.95% from a year ago.
• During the quarter, 18 of these 38 funds increased positions in CTM, 11 reduced exposure, and 9 held steady.
• Altogether, these fund groups held 10.2Mn shares in CTM by December 2025, up by 4.85Mn shares quarter on quarter, and up 5.41Mn shares year over year.
• As of December 31, 2025, the biggest holder of Castellum is VANGUARD CAPITAL MANAGEMENT LLC at 3.08Mn shares, representing 3.43% of shares outstanding.
• The biggest buyers of Castellum for the quarter ending December 2025 included VANGUARD CAPITAL MANAGEMENT LLC (3.08Mn), CAPTRUST FINANCIAL ADVISORS (626.1K), VANGUARD FIDUCIARY TRUST CO (418.32K), GEODE CAPITAL MANAGEMENT, LLC (171.18K), Meridian Wealth Management, LLC (40.65K).
• The biggest sellers of Castellum for the quarter ending December 2025 included UBS Group AG (2.0Mn), Sei Investments Co (211.5K), JANE STREET GROUP, LLC (107.07K), Northern Trust Corp (28.71K), Citigroup Inc (19.79K).
• Per Business Quant data, the top 10 holders of Castellum for the quarter ending December 2025 are VANGUARD CAPITAL MANAGEMENT LLC (3.08Mn), GEODE CAPITAL MANAGEMENT, LLC (944.9K), Meridian Wealth Management, LLC (785.8K), CAPTRUST FINANCIAL ADVISORS (626.1K), VANGUARD FIDUCIARY TRUST CO (418.32K), State Street Corp (303.9K), BlackRock, Inc. (265.49K), JANE STREET GROUP, LLC (236.77K), Savvy Advisors, Inc. (221.8K), Northern Trust Corp (181.9K).