Medium and longer-dated U.S. Treasury notes rose on Monday, as S&P Futures fell, pressured by the ongoing fall in oil prices.

Yields on benchmark 10-year bonds—used to calculate mortgage rates and other consumer loans—fell to 2.119 percent.

Two-year and five-year bonds traded sideways.

Brent crude for February delivery fell to $ 55.70 per barrel, while U.S. light crude futures extended declines to a third day to $ 52.00. The declines could pressure U.S. energy stocks on Monday.