Castellum

Castellum

Castellum was formed in 2019 by CEO Mark Fuller, a veteran of the government technology sector who co-founded the defense contractor ATS Corporation, and his later venture Whitestone Group. The company structured itself from the outset as a holding vehicle designed to consolidate profitable but subscale federal IT and cybersecurity firms — businesses that serve the U.S. Department of Defense and other national security agencies. The company's strategy is to acquire and integrate small to midsized government contractors specializing in cybersecurity, information warfare, electronic warfare, and software engineering. Public filings show a focus on companies with established contract vehicles, past performance qualifications, and prime contractor status with agencies like the U.S. Navy. Completed acquisitions include Mainnerve Federal Services, a cybersecurity firm, and Merrison Technologies, an IT services contractor, both announced in 2021. Other subsidiaries brought in-house that year were Corvus Consulting and Lexington Solutions, reflecting a doubled-down procurement spree. Castellum operates primarily in the United States, centered on the federal procurement hubs of the Mid-Atlantic and the Carolinas. The company's executive team includes President Glen Ives, a former naval aviator and commanding officer who joined in 2021 — a deliberate signal to Pentagon clients that Castellum understands uniformed leadership. Total deployment figures are not centrally published, but SEC filings in 2024 registered a shelf offering intended to raise capital for future acquisition activity, signaling a continued buy-and-build appetite. The firm remains small relative to government services giants, publicly reporting annualized revenues around $40–45 million in its 2023 filings. Castellum differs from a pure-play venture firm or a family office: it is a publicly traded roll-up (NYSE American: CTM) with an executive team populated by former military officers. That public listing raises its profile with the procurement establishment, even as it absorbs the reporting costs. Its structural differentiator is using a public currency to acquire private contractors that, individually, lack the scale to win larger defense task orders — then stitching them into a platform that can compete for prime positions. The succession and targeting playbook depends entirely on Fuller and Ives's ability to source, price, and integrate new acquisitions while managing the overhead of being a micro-cap public entity.