U.S. government debt prices were lower on Monday as the expected fallout from Italy's No vote failed to materialize.
Italian Prime Minister Matteo Renzi is expected to resign after a "clear" rejection of legislative reform measures however the market reaction has so far been largely muted.
Earlier, the yield on the Italian 10-year note neared a session high of 2.062 percent. It has since fallen back below 2 percent.
In economic news, the November IHS Markit non-manufacturing index came in at 54.6, marking the ninth consecutive month in which the services sector has shown expansion. "Survey respondents noted that improved client confidence and a favourable domestic economic backdrop had helped to boost business activity in November," IHS said.
The November ISM services index read, meanwhile, came in at 57.2, above an October read of 54.8.
In oil markets, U.S. crude settled up 11 cents at $51.79 a barrel, the best close since July 2015.