* Obama calls for lower corporate tax rate
* Boeing tumbles after results, forecast
* Fed seen touting improved outlook
* Indexes: Dow flat, S&P up 0.3 pct, Nasdaq up 0.5 pct (Updates with quote, Allegheny Tech, changes byline)
By Rodrigo Campos
NEW YORK, Jan 26 (Reuters) - U.S. stocks rose on Wednesday as U.S. President Barack Obama's call for a lower corporate tax rate offset a weak outlook from Boeing.
Investors awaited comments from the U.S. Federal Reserve, which is expected to nod to an improving economic outlook as it reaffirms a plan to buy government debt to help speed the recovery. A Fed statement is expected at about 2:15 p.m. EST (1915 GMT).
"The Fed continues to say even in an improving U.S. economic environment it is going to continue its stimulus activity," said Tim Speiss, chairman of the personal wealth division at EisnerAmper in New York. "The market is reacting positively to continued Fed intervention."
Boeing Co fell nearly 4 percent, weighing on the Dow.
Commodity shares got a boost after Allegheny Technologies Inc forecast stronger sales in 2011, helped by higher base prices for metals and a stronger aerospace and defense market. Allegheny rose 8.2 percent to $63.16, leading the S&P materials sector, which was up 1 percent.
In his State of the Union address to Congress on Tuesday night, Obama asked lawmakers to work with him to cut the corporate tax rate and simplify the tax code, moves that could lead to higher corporate profits.
The Dow Jones industrial average dipped 3.94 points, or 0.03 percent, to 11,973.25. The Standard & Poor's 500 Index gained 3.62 points, or 0.28 percent, to 1,294.80. The Nasdaq Composite Index added 13.51 points, or 0.50 percent, to 2,732.76.
The Dow briefly traded above 12,000 for the first time since June 2008.
Boeing dropped nearly 4 percent to $69.44. The planemaker posted a drop in quarterly profit and offered a disappointing forecast partly due to delays in its new 787 Dreamliner.
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 advanced 1 percent, with Hovnanian Enterprises Inc adding 3.1 percent to $4.60, and KB Home up 3.6 percent to $15.80.