Ample Reserves Regime

Before 2008 the Federal Reserve kept bank reserves scarce and nudged the federal funds rate by adding or removing small amounts each day. After the crisis, reserves became enormous. In an ample reserves regime, the Fed stopped fiddling with the quantity and steers rates with 'administered' rates instead, mainly the interest it pays on reserve balances.

Think of it as setting the floor of a room rather than counting the people in it. For traders, it is why Fed balance-sheet decisions and money-market plumbing now get so much attention.