U.S. stocks rose on Wednesday with the S&P 500 hitting a 29-month high, led by gains in commodity and tech shares after the U.S. Federal Reserve gave a lukewarm economic assessment.

Following a two-day meeting, its first of the year, the Fed said high unemployment still justified a $600 billion bond-buying program that has helped equities rally in the last few months.

You had a relief rally at first on the simple fact that there were no dissents, said Cary Leahey, managing director and senior economist at Decision Economics in New York.

There was very little change in the statement. The Fed is reluctant to upgrade its assessment of the economy and reminded us that whatever growth we've had, hasn't brought the unemployment rate down very much.

The Dow Jones industrial average <.DJI> was up 27.74 points, or 0.23 percent, at 12,004.93. The Standard & Poor's 500 Index <.SPX> was up 7.20 points, or 0.56 percent, at 1,298.38. The Nasdaq Composite Index <.IXIC> was up 22.36 points, or 0.82 percent, at 2,741.61.

The Dow traded above 12,000 earlier for the first time since June 2008, but retreated in afternoon trade and then popped back up above the psychologically important level.

Blue-chip Boeing Co fell 3.1 percent to $70 after the U.S. plane maker posted a drop in quarterly profit and offered a disappointing forecast.

But commodity shares got a boost after Allegheny Technologies Inc forecast stronger sales in 2011, helped by higher base prices for metals. The stock surged 10.3 percent to $64.39.

The S&P materials sector index <.GSPM> rose 1.9 percent.

Network equipment maker Juniper Networks Inc's quarterly sales beat Wall Street's expectations and its shares climbed 6.7 percent to $37.16, while Fortinet shares jumped 14.1 percent to $38.70 a day after the network security systems provider reported market-beating quarterly results.

Thomson Reuters' latest data showed 69 percent of the 144 S&P 500 companies that have reported earnings so far have beat estimates.

The S&P 500 index continues to show overbought readings in various short-term technical indicators after last week's decline released some selling pressure.

Short-term support kicks in at 1,284, its 14-day moving average, while the 1,300-1,305 area, which are closing highs reached in August 2008, could result in resistance.

Late on Tuesday, U.S. President Barack Obama's call on Tuesday for a lower corporate tax rate also supported equities, as any move in that direction is seen as a boost to profits.

In the latest economic data, new U.S. single-family home sales rose in December to their highest level in eight months. The PHLX housing index <.HGX> advanced 1 percent, with Hovnanian Enterprises Inc adding 6.5 percent to $4.75.

(Reporting by Angela Moon; Editing by Jan Paschal)