The benchmark will have its last fixing at around 6:55 a.m. New York time on Friday, and some borrowers and lenders are still scrambling to amend contracts.

Economists still expect to see a recession but are pushing back projections of the downturn's start date.

The impending barrage of T-bills is a precursor to a glut of longer-term debt issues, which might result in a "demand vacuum" for longer-maturity bonds that pushes yields higher and tightens financial conditions.

After Jerome Powell told the House Financial Services Committee that the Fed might keep raising interest rates, the gap between yields on 2-year and 10-year Treasuries—which has inverted before each of the past five U.S. recessions—reached the largest inversion since March.