An accounting trick in which a company classifies a short-term loan as a sale and subsequently uses the cash proceeds from said sale to reduce its liabilities. In the repo market, companies are able to gain access to the excess funds of other firms for short periods in exchange for collateral (usually a bond). The company that borrows the funds will promise to pay back the short-term loan with a small amount of interest and the collateral typically never changes hands. This is what allows firms to record the incoming cash as a sale; the collateral is assumed to have been "sold off" and bought back later.

Repo 105 made headlines following the collapse of Lehman Brothers. It was reported that Lehman accountants used the accounting maneuver to pay down $50 billion in liabilities to reduce leverage on their balance sheet before earnings were announced. This made it look like Lehman was much less reliant on debt than it actually was.