By Joseph Adinolfi, MarketWatch

NEW YORK (MarketWatch)--U.S. Treasury yields finished the day higher Thursday for the second consecutive session a day after Federal Reserve Chairwoman Janet Yellen reassured markets that, once the Fed begins raising interest rates, it would be careful to do so gradually.

Ten-year and 30-year Treasury yields rose to their highest levels in two weeks. The 10-year rose 5.6 basis points to 2.206% (10_YEAR) while the 30-year yield (30_YEAR) was up 6.4 basis points at 2.815%. The five-year yield gained 4.5 basis points to 1.663%. The two-year (2_YEAR) yield rose 2.4 basis points to 0.637%, according to data from Tradeweb.

Bond yields rise as prices fall.

Before Yellen's news conference, the Fed's monetary policy statement confounded the market's expectations by appearing slightly more dovish than the market expected, analysts said. The Fed modified its guidance, adding that the Fed would be "patient" about raising rates to language saying rates would remain near zero "for a considerable time."

During the question-and-answer session, Yellen adopted a hawkish tone, saying that the Fed wouldn't begin raising rates for "at least the next couple of meetings," according to several analysts, including Camilla Sutton, chief FX strategist at Scotiabank.

U.S. stocks moved higher for a second session Thursday, after recording their best session of 2014 on Wednesday and ending a monthlong stretch of risk-averse trading. The Dow Jones Industrial Average (DJI) gained 421.28 points, or 2.43%, its biggest one-day percentage gain since December 2011. This marks the first time in six years that the index has gained more than 200 points for two straight sessions.

Donald Ellenberger, senior portfolio manager and head of multi-sector strategies at Federated Investors, said this is a sign that the market trusts that the Fed will be careful to hike rates gradually.

"Yellen's statement had something in it for everyone, but the one thing you can take out of the market's reaction, it seemed to be 'risk on,' " Ellenberger said.

The conference followed the Federal Open Market Committee's two-day December monetary policy meeting, which ended Wednesday afternoon. The Fed won't meet again until Jan. 28.

Here's what bond investors were watching Thursday:

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