What is the historical shortest initial maturity for T-bills?

The historical shortest initial maturity for Treasury bills (T-bills) is 4 weeks. T-bills are short-term securities issued by the U.S. government, and they are known for their very short maturities, which typically range from a few days to one year.

When T-bills were first introduced, the shortest maturity offered was indeed 4 weeks. This maturity period has remained a standard offering, providing investors with a vehicle for short-term investment and liquidity.

The other choices include some common T-bill maturities, but they do not represent the shortest historical initial maturity. For instance, while 1 month and 26 weeks are valid T-bill maturities, the specific historical minimum initial maturity is recognized as being 4 weeks.