Repo

http://www.derivativesstrategy.com/magazine/archive/1997/0297fea1.asp

Repo, officially the sale of securities with a simultaneous commitment to repurchase them in the future, was traditionally a financing vehicle used by banks to raise money off their bond portfolios.
In a standard repo, the cash borrower puts up a portion of the bond portfolio as collateral and the lender advances cash. For bond-rich investors, repo meets their top-three money market requirements: it's flexible (with time frames from intra-day to three months); it's safe (because it is a collateralized loan); and it often offers the best yields when compared to other alternatives.
Now, among other things, it greases the wheels of even the most mundane derivatives trades. Say a trader buys an option and hedges it with the purchase of the underlying bond. A repo would be used to fund the purchase of the bond.
Hedge funds typically use REPOs in exotic OTC transactions, they can't do one of these trades without repo. Conceptually, the repo is used to finance the hedge portion of a complex OTC transaction. And hedges come in all shapes and sizes. That means that in some cases the repo may be done in the currency of the original swap or option. In other cases, in order to pick up more yield or put on a different risk spin, a cross-currency repo could be used.
Repo is thought of as a short-term vehicle-overnight repo is the most popular form-but it is possible to extend the repo term to a year and beyond.