Excess reserves are bank reserves held by a bank in excess of a reserve requirement for it set by a central bank. In the United States, bank reserves for a commercial bank are represented by its cash holdings and any credit balance in an account at its Federal Reserve Bank (FRB). Holding excess reserves long term may have an opportunity cost if higher risk-adjusted interest can be earned by putting the funds elsewhere. For banks in the U.S. Federal Reserve System, excess reserves may be created by a given bank in the very short term by making short-term (usually overnight) loans on the federal funds market to another bank that may be short of its reserve requirements. Banks may also choose to hold some excess reserves to facilitate upcoming transactions or to meet contractual clearing balance requirements. The total amount of FRB credits held in all FRB accounts for all commercial banks, together with all currency and vault cash, forms the M0 monetary base. Impact on inflation of excess reserve balances Research by personnel at the Fed has resulted in claims that interest paid on reserves helps to guard against inflationary pressures. Under a traditional operating framework, in which central bank controls interest rates by changing the level of reserves and pays no interest on excess reserves, it would need to remove almost all of these excess reserves to raise market interest rates. Now when central bank pays interest on excess reserves the link between the level of reserves and willingness of commercial banks to lend is broken. It allows the central bank to raise market interest rates by simply raising the interest rate it pays on reserves without changing the quantity of reserves thus reducing lending growth and curbing economic activity. Nobel-prize winning economist Eugene Fama contends that paying interest on reserves has (in effect) increased the supply of short-term debt, which through standard demand/supply effects would increase bond yields. The post-GFC low interest-rate environment has therefore persisted in spite of, not because of the actions of the Federal Reserve. Specifically, the demand for risk-free assets (caused by the post-crisis 'flight to quality') has dominated the effect of paying interest on reserves on overall interest rates. He has also argued that paying interest on reserves has protected against hyperinflation of the US dollar. Interest on excess reserves In the United States (2008-) The Financial Services Regulatory Relief Act of