Longer-dated U.S. Treasurys prices edged up briefly early Monday after data on personal spending and consumption expenditure suggested a moderation of economic activity in late 2014, supporting bets the Federal Reserve might not raise rates until late 2015.
On Monday, 10-year notes yielded 1.67 percent, around lows last seen in 2013, reflecting a price decline of 7/32. Benchmark 10-year notes broke below the key 1.7 percent mark on Friday.
Prices on the 30-year Treasurys bond were up as much as 5/32 after the December data before paring those gains.
The 30-year yield was last 2.25 percent, down 17/32 in price.
The Institute for Supply Management (ISM) said its index of national factory activity fell to 53.5 from 55.1 the month before. The reading was shy of expectations of 54.5, according to a Reuters poll of economists.
Earlier, the Commerce Department said consumer spending dropped 0.3 percent after a downwardly revised 0.5 percent increase in November. It was the largest drop since September 2009.
The core personal consumption expenditure (PCE) index that excludes volatile food and energy prices was unchanged for a second straight month. The Fed's preferred inflation gauge increased 1.3 percent in the 12 months through December.
Asian data out early in the day showed that manufacturing activity in China is still contracting. China's final HSBC Purchasing Managers' Index (PMI) fell to 49.7 in January, a touch below its 49.8 flash reading. The 50-point mark separates expansion from contraction.
Greece's new left-wing government began what one analyst called a "charm offensive" on Sunday, in an effort to persuade its euro zone partners to soften the terms of its international bailout. The government has already started to reverse austerity measures unpopular in Greece that were a condition of its current bailout agreement.