U.S. government debt prices were lower on Thursday as investors looked to several pieces of data and kept a close eye on the U.K., where Britons have begun to vote on whether to remain in or leave the European Union.
Opinion polls taken before the vote indicated the outcome is too close to forecast, although two polls published late on Wednesday suggested a swing towards remain.
Much will depend on turnout, with younger Britons seen as more supportive of the EU than their elders but less likely to vote.
Polling stations opened at 0600 GMT and will close at 2100, with results expected to be announced by the 382 individual local counting areas between around 0100 and 0300 on Friday.
Prime Minister David Cameron called the vote under pressure from the anti-EU wing of his Conservative Party and the surging UK Independence Party (UKIP), hoping to end decades of debate over Britain's ties with Europe.
The yield on the benchmark 10-year Treasury note, which moves inversely to its price, sat higher at 1.7442 percent, while the yield on the 30-year Treasury bond was also higher at 2.5563 percent. Two-year note yields also rose, last trading at 0.7776 percent.