Financial institutions are obligated by law to maintain certain levels of reserves, either as reserves with the Fed or as vault cash. The level of these reserves is determined by the outstanding assets and liabilities of each depository institution, as well as by the Fed itself, but is typically 10% of the total value of the bank's demand accounts (depending on bank size). For transaction deposits of size $9.3 million to $43.9 million (checking accounts, NOWs, and other deposits that can be used to make payments) the reserve requirement in 2007–2008 was 3 percent of the end-of-the-day daily average amount held over a two-week period. Transaction deposits over $43.9 million held at the same depository institution carried a 10 percent reserve requirement.