Definition of tail

1. in U.S. Treasury auctions, the price spread between the average competitive bid on bills, notes, and bonds sold in Treasury auctions and the stopout price.
2. money market term for a financial instrument partially financed by a repurchase agreement. For example, a dealer buys a 90-day Treasury bill and sells a 30-day repurchase agreement. The maturity difference between the two is the tail.
3. Finance. The figures appearing after the decimal point in a bond quotation. For example, in a bid of $95.3712, the tail is .3712. Bond prices also are quoted in dollars plus 32/100 of a dollar.
4. Estates. The property inherited by direct descendents, for example, children or grandchildren of a decedent. Called an estate in tail.

Insurance: interval between receipt of premium income and payment of claims. For example, reinsurance companies have a long tail as compared to casualty-insurance companies.
Treasury auctions: spread in price between the lowest competitive bid accepted by the U.S. Treasury for bills, bonds, and notes and the average bid by all those offering to buy such Treasury securities. See also treasuries.
Underwriting: decimal places following the round-dollar amount of a bid by a potential underwriter in a competitive bid underwriting. For instance, in a bid of $97.3347 for a particular bond issue, the tail is .3347.