Rates are increasing in the $4 trillion repurchase agreement market. The repurchase agreement market or repos market is the main source of short term funding for firms in the financial markets. Borrowers put up Treasury securities as collateral. The difference beween the value of the collateral and the cash loan amount is known as the "haircut." The current collateral requirement is $102 of Treasurys for $100 in cash loan. If the U.S. is downgraded to AA the collateral could go up to $103 or higher. This would lead to firms coming up with more Treasury securities for loans. The rate for overnight transactions also goes up. The rate was up form 0.01 % to 0.1% in the last week. The result could be dislocation in financial markets as firms have to come up with more collateral and pay higher repo rates, and some firms prefer to hold cash.