The stimulative effect of the Federal Reserve's credit easing policies depends sensitively on the particular mix of lending programs and securities purchases that it undertakes.
When markets are illiquid and private arbitrage is impaired by balance sheet constraints and other factors, as at present, one dollar of longer-term securities purchases is unlikely to have the same impact on financial markets and the economy as a dollar of lending to banks, which  BIS Review 3/2009  5  has in turn a different effect than a dollar of lending to support the commercial paper market.