Caption Management

William Cooper serves as founder and sole Chief Investment Officer, retaining full authority over all capital allocation. He previously spent nine years as a portfolio manager in Citadel's Global Equities business, running one of the firm's most profitable books before leaving to launch Caption in 2020.

Caption operates a hybrid structure running a concentrated long/short public equities book alongside direct venture capital investments and private structured credit. The firm was seeded with a roughly $200 million commitment that allowed it to pursue multiple strategies from day one. In 2024, Bloomberg reported the firm was raising a dedicated venture vehicle, signaling formal separation of the private-market strategy.

Cooper's pipeline draws heavily on relationships from his Citadel network and co-investor ecosystem, with D1 Capital Partners — an early backer — providing shared access to late-stage growth opportunities. The firm has focused on US and Indian technology companies, participating in rounds alongside other institutional crossover investors.

Ken Griffin personally seeded the firm at launch, with D1 Capital Partners adding a significant commitment shortly after. Institutional Investor reported in 2021 that the combined backing was roughly $200 million, giving Caption immediate operational scale unusual for a first-time fund manager.

Publicly identifiable positions include Indian edtech company Byju's and Celsius Network during its bankruptcy restructuring, per court filings in 2023. The firm has also been active in crypto infrastructure and token-linked instruments, though the portfolio's full composition remains largely private.

Caption does not publicly report AUM or returns. The firm has maintained a low profile since launch, consistent with the operational norms of multi-manager platforms that typically restrict disclosure to limited partners and not the broader market.

Caption is based in Miami, Florida, part of a post-2020 wave of financial firms relocating from Chicago and the Northeast. The firm invests across US public and private markets and maintains an active emerging-market practice, with a particular concentration in Indian technology companies.