Multi-Prime and Counterparty Diversification

Before 2008, it was common for a hedge fund to use a single prime broker for nearly everything — financing, custody, securities lending, trade execution. That concentration was convenient: one relationship, one set of paperwork, better financing terms from being a bigger client to that one broker. It also meant a fund's fate was tied to that one broker's solvency, a risk that seemed theoretical until Lehman Brothers filed for bankruptcy in September 2008.

Funds that used Lehman's UK prime brokerage arm as their sole prime broker discovered that assets pledged as collateral there, particularly under UK rehypothecation rules that let the broker re-use client collateral more freely than US rules did, were frozen in the bankruptcy proceedings for years. It didn't matter whether the fund's own trading had gone well — its cash and securities were tied up inside a failed institution's estate, and getting them back meant standing in line with every other creditor. Funds with only one prime broker had no fallback: no other financing line to draw on, no other custody arrangement holding a copy of their assets.

Multi-prime is the practical response: a fund splits its business across two, three, or more prime brokers, so that no single broker's failure can freeze the fund's entire book. If one prime broker gets into trouble, or simply has a bad quarter and tightens its risk appetite, the fund can shift positions and financing to another relationship rather than being stuck. Multi-prime also creates negotiating leverage — a fund that can credibly move business elsewhere gets better financing terms than one that has nowhere else to go.

The tradeoff is real: running multiple prime relationships means duplicated operational work, more complex reconciliation across brokers, and often worse pricing on any single relationship because the fund's business is split into smaller pieces, none of which is as attractive to any one broker as a larger, exclusive relationship would be. Large multi-strategy funds absorb this cost readily because counterparty safety is worth more to them than the marginal financing discount; smaller funds sometimes stay single-prime simply because they lack the scale or operational staff to manage several relationships at once, accepting the concentration risk as a cost of being small.