Ken Griffin Has Another Money Machine to Rival Hedge Fund(Bloomberg) Citadel Securities is sometimes dismissively referred to as “Citadel’s trading arm” — seen as a forgotten backwater of Ken Griffin’s hedge fund empire, where quants toil on complex algorithms to arbitrage tiny differences in stock prices or calculate bid-ask spreads for Treasuries. It’s much more than that. The market-making firm, which is actually separate from Griffin’s hedge fund, generated $3.5 billion of revenue last year — vastly outpacing nonbank peers and catching up with Wall Street rivals.