The US government gives out debt of varying duration. Generally speaking, the shorter the duration the lower the interest rate and the higher the liquidity ("ea

The US government gives out debt of varying duration. Generally speaking, the shorter the duration the lower the interest rate and the higher the liquidity ("ease of conversion to cash"). Treasury bills are is debt with a duration of less than a year and BRK has a lot of those: https://www.investopedia.com/terms/t/treasurybill.asp https://www.investopedia.com/terms/t/treasurybill.asp