In economics, Float makes up the smallest part of the money supply. Float occurs when there is a delay in the clearing of payments between banks. It is most obvious in the time delay between when you write a check and when the funds to cover that check are deducted from your account.

Once the holder of your check deposits it in his account, his bank immediately credits (increases) his account, assuming that your bank will ultimately send the funds to cover the check. Until your bank actually sends the funds, both you and the holder of the check have the "same" money in both of your accounts.

Once his bank notifies your bank, the "duplicate" funds are removed from your account.

Float causes marginal changes in the money supply. Before electronic check clearing, bad weather or communication problems often caused float to significantly increase, as the clearing of checks was delayed. In some cases, the Federal Reserve had to engage in open market operations to counteract the effects of changing float.