Wall Street’s Big Three Consolidate Power in AI-Driven Equities Boom

The five largest investment banks have collectively generated $67 billion in equities revenue through September 30, already surpassing their full-year results for 2025. This surge stems from ballooning market valuations and heightened investor activity across stocks, ETFs, and derivatives. Wells Fargo analyst Mike Mayo notes that the Big Three view each other as their sole true competitors, positioning them to dictate the terms of the current market cycle.

Prime brokerage services have emerged as the primary engine for this growth. By providing hedge funds with margin loans and securities lending, these banks allow institutional clients to amplify their bets on AI hardware and hyperscalers. Goldman Sachs reported a 96% jump in equities financing activities during the third quarter, reaching a record $3.37 billion. While JPMorgan and Morgan Stanley provide less granular reporting, executives confirm a similar trend. JPMorgan CFO Jeremy Barnum characterized the current environment as one of insatiable demand for capital, noting that AI remains the primary driver behind the diverse mechanisms through which clients are tapping into bank liquidity.