The past 18 months has been tumultuous for the prime brokerage industry. On Sept. 15, 2008, the day Lehman Brothers filed for bankruptcy, hedge funds woke up to the fact that their assets could actually be frozen if a large bank failed. The practice of using multiple prime brokers and having several custody relationships took on new urgency. Hedge funds began to reevaluate their existing prime brokerage relationships en masse.