15  In carrying out normal discount window operations, the Fed absorbs virtually no credit risk because the borrowing bank remains responsible for repaying the discount window loan even if the issuer of the asset used as collateral defaults. Hence both the private issuer of the asset and the bank itself would have to fail nearly simultaneously for the Fed to take a loss.
The fact that the Fed bears no credit risk places a limit on how far down the Fed can drive the cost of capital to private nonbank borrowers. For various reasons the Fed might well be reluctant to incur credit risk, as would happen if it bought assets directly from the private nonbank sector.