Those looking for a substantial return on their money, should probably avoid purchasing U.S. Treasury bills any time soon.

The return on some short-term notes fell below zero again late last week as investors and international central banks bought the government securities.

Analysts say the big money is simply looking for a safe place to park their cash for the time being until they put it to work again.

Despite the growing U.S. debt, international demand for Treasury securities is still growing.