Treasury bills are government issued securities that are most frequently used as a short-term investment tool. They are also known as T-bills and are sold in denominations starting from $1,000 to $1 million. Treasury bills are considered one of the safest types of investments because they are backed by the US government. In the financial world, treasury bills are often referred to as a "risk-free" investment. Other terms that are synonymous with treasury bills include government bonds or bills, T-bonds, T-notes, and US Treasury securities. Regardless of the terminology used, these investments are highly sought after by investors who are looking to achieve modest returns with low risk.