Treasury Bills T-bill Treasury Bills U.S. T-bill TBILLS Treasury Bills Letras del Tesoro Certificados de Tesorería כתבי האגרה של האוצר ट्रेज़री बिल्स TBILLS A Treasury Bill (T-Bill) is a short-term U.S. government debt obligation backed by the Treasury Department with a maturity of one year or less. Treasury bills are usually sold in denominations of $1,000. However, some can reach a maximum denomination of $