The size of the monetary policy funds rate shortfall has also caused the Fed to expand its use of unconventional policy tools that change the size and composition of its balance sheet.The Fed started to employ these balance sheet tools in late 2007 as unusual strains and dislocations in financial markets clogged the flow of credit.Typically,changes in the funds rate affect other interest rates and asset prices quite quickly. However,the economic stimulus from the Fed’s cuts in the funds rate was blunted by credit market dysfunction and illiquidity and higher risk spreads. Accordingly, the Fed started to lend directly to a broader range of counterparties and against a broader set of collateral in order to enhance liquidity in critical financial markets,improve the flow of credit to the economy,and restore the full effect of the monetary policy interest rate easing