A T-bills time to maturity is known at the time of purchase. Its duration in Canada is less than one year. At maturity, the government that issued will pay its predetermined value. Your profit is the difference between that price and the discounted price you purchase it at. Treasury bills have maturities of 1 month, 2 months, 3 months, 6 months or 1 year. They are easy to resell before their maturity, so they are a very liquid investment.