US Treasury prices rose on Tuesday as the discovery of a deadly poison in a Senate Office building sparked a bid for safe-haven government debt.
A pullback in US car and truck sales in January suggested a primary source of economic growth might be petering out, lending further support to bonds.
Chicago Federal Reserve President Michael Moskow also helped the market along when he said concern about rising inflation was premature and that disappointing job growth remained a key area of weakness for the economy.
Collectively, that was sufficient to push the market modestly higher, though the rally was nothing to write home about.
"The market has slowly come to the realisation that strong growth and low inflation is not going to give you the impetus to move rates significantly in either direction," said Mark Mahoney, Treasury strategist at UBS.
That proved true on Tuesday, with the 10-year note US10YT=RR climbing a subdued 12/32 for a yield of 4.10 percent from 4.15 percent late Monday.
Yields, which move in the opposite direction to price, had yawned as high as 4.20 percent last week after the Fed unexpectedly dropped its promise to keep interest rates low for a "considerable period."
The Fed's revamped statement said only that the central bank could be "patient in removing policy accommodation."
But Moskow, the first Fed official to speak since the wording alteration, signalled there was no urgent need to hike rates to fend off inflation.
That left the interest rate-sensitive two-year note up 3/32 to yield 1.76 percent against 1.81 percent on Monday.
Five-year notes gained 8/32 to yield 3.11 percent, versus 3.15 percent. Thirty-year bonds rose 16/32 to yield to 4.95 percent from 4.99 percent.
While car sales figures were still pouring in, the results looked disappointing. Things were not looking good for auto giants General Motors Corp and Ford Motor Co, whose US vehicle sales fell 2 percent and 5.2 percent respectively from a year earlier.
"Cars seem to be pivotal in keeping the wheels of consumer spending turning and certainly this quarter is starting out with a thud," said Chris Rupkey, senior financial economist at Bank of Tokyo-Mitsubishi.
"So it's going to be very hard to get 4.5 percent GDP growth for the first quarter," he said.
In a further boon to Treasuries, the Bank of Japan was thought to have intervened again to limit the yen's rise. Traders assume a portion of any dollars bought would end up in bonds.
The BOJ was not alone. The Bank of Korea on Tuesday reported its reserves grew $2.1 billion in January to hit a record $157 billion. Dealers anticipated much of that would be funnelled into Treasury paper.