By Min Zeng 

Treasury bonds posted the biggest one-day selloff in three months on Wednesday as comments from Federal Reserve Chairwoman Janet Yellen renewed some concerns that the central bank may raise interest rates sooner than many investors anticipate.

The selloff followed a rally a day earlier that had sent the yield on the benchmark 10-year note to the lowest level in more than a year. Some traders said Ms. Yellen's remarks, along with stabilization in Russia's currency from recent turmoil, drove investors to cash in some chips from the Treasury market.

In late-afternoon trading, the yield on the 10-year note rose to 2.146% compared with 2.07% a day earlier.

The yield rose by about 0.08 percentage point, the most on a daily basis since September.

When bond yields rise, their prices fall.

The Fed concluded its two-day monetary policy meeting Wednesday afternoon. In a statement, the central bank continued to signal patience in raising interest rates. In a subsequent press conference, Ms. Yellen said the Fed won't raise interest rates for at least the "next couple of meetings."

The comments raised anxiety in the bond market that a rate increase could come as soon as the April 2015 policy meeting. That will be sooner than the second half of 2015 that many investors currently expect. Ms. Yellen has long been a leading advocate of keeping interest rates near zero to support the economy.

"The bond market took the comments as more hawkish," said Adrian Miller, director of fixed-income strategies at GMP Securities LLC in New York. "The Fed chair is never that specific" in talking about the timing of interest-rate policy.

Higher interest rates will make newly-issued bonds more attractive, depressing the value of existing bonds held by investors.

Demand for ultrasafe Treasury bonds has climbed this year and picked up more momentum earlier this week. The 10-year yield closed at the lowest level on Tuesday since May 2013 as the ruble in Russia hit a record low against the dollar amid market turmoil. The yield has fallen from 3% at the start of the year.

Global data continued to show faltering economic growth overseas even as the U.S. economy has gained traction.

Meanwhile, the ripple effects of a prolonged rout in oil prices continued to shake out in financial markets. Lower oil prices have hurt the growth outlook in countries where energy exports play a large role in the economy. Many investors have shed financial assets in emerging markets and moved cash into haven U.S. government bonds.

Lower oil prices have soothed concerns over inflation--a main threat to the value of fixed income assets. Inflation chips away investors' fixed returns over time. A slower pace of inflation preserves investors' investments in fixed-income assets.

Earlier Wednesday, a report showed U.S. consumer prices last month posted a 0.3% drop, the steepest decline on a monthly basis since December 2008, the latest sign of impact from falling oil prices. Stripping out energy and food, inflation remains contained, rising by 0.1% and matching economists' forecasts.

U.S. Treasury debt overall has posted a total return, reflecting price appreciation and interest payments, of 5.45% this year through Tuesday, according to Barclays PLC. Over the same period, the S&P 500 has returned 8.85%, while low-rated corporate bonds, known as junk bonds, posted a loss of 0.31%, erasing a strong rally earlier this year.

COUPON  ISSUE   PRICE      CHANGE   YIELD     CHANGE 
1/2%    2-year 99 25/32    dn 3/32  0.609%     +4.8BP 
1%      3-year 99 26/32    dn 7/32  1.064%     +7.2BP 
1 1/2%  5-year 99 16/32    dn 12/32 1.604%     +7.8BP 
1 7/8%  7-year 99 20/32    dn 16/32 1.933%     +7.6BP 
2 1/4%  10-year 100 30/32  dn 22/32 2.146%     +6.6BP 
3%      30-year 105 10/32  dn 24/32 2.733%     +3.6BP 
2-10-Yr Yield Spread: +153.7BPS +151.0BPS 
 
Source: Tradeweb/WSJ Market Data Group 

-- Write to Min Zeng at min.zeng@wsj.com