Castellum CTM Institutional Ownership

Ownership Summary

Castellum, Inc. (NYSE:CTM) showed up in the 13F filings of 27 institutional investors as of March 2026.

• Their combined ownership stood at 8.2% of outstanding shares in March 2026, down from 11.3% in December 2025.
• Their total shares held in CTM increased 37.0% quarter over quarter, and separately, investors owning Castellum increased 3.85% from a year ago.
• Activity in CTM broke down as 12 buyers, 5 sellers, and 10 unchanged among 27 total holders.
• Institutional investors collectively held 7.74Mn shares in Castellum as of March 2026, up by 2.09Mn shares quarter on quarter, and up 4.42Mn shares year over year.
• VANGUARD CAPITAL MANAGEMENT LLC is the top holder of Castellum as of March 31, 2026, with 3.08Mn shares representing 3.26% of outstanding stock.
• The largest buyers of Castellum for the quarter ending March 2026 were 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 March 2026 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 March 2026 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).