Highlights:

* Boeing , down 3.7 percent to $42.12, was the top drag on the Dow after a broker downgrade. The sell-off also hit shares of other bellwethers including General Electric , down 5.8 percent to $14.92.

* Fed Chairman Ben Bernanke revived hopes that the government could start buying toxic assets from banks and provide fresh capital to beleaguered banking sector, helping to avert a broad market decline.

* The S&P and Nasdaq were little changed.

(Editing by Leslie Adler)