Rates on Treasury bills maturing around the time the U.S. is forecast to run out of money to pay its obligations are higher than those on longer-maturity securities, suggesting investors are concerned lawmakers may fail to agree to lift the debt ceiling.

Feb. 28 bill rates rose to 0.108 percent, an increase of 2 basis points, or 0.02 percentage point, and the highest since Nov. 14. That compares with 0.08 percent for bills due April 18. At the end of last year, the April bills yielded 7 basis points more than the February securities.