Securities lending (SL) is one of the less-well-publicized shadow banking activities. Like repurchase agreements (repo) and asset-backed commercial paper, SL can be a source of very short-term wholesale funding, allowing a shadow bank to engage in the kind of liquidity, maturity and credit transformation that banks do. And, like other short-term funding sources, it can suddenly dry up, making it a source of systemic risk. When funding evaporates, fire sales and a credit crunch follow.

Indeed, SL played a supporting role in the 2007-09 financial crisis, being partly responsible for the collapse of the large insurance company AIG when the market seized in September 2008 (see chart). While SL has not garnered the attention of capital and liquidity regulation or central clearing, or even repo markets, it is still worth understanding what securities lending is and the risks it poses. That is the purpose of this post...