May 7 (Reuters) - U.S. stock indexes opened slightly

higher on Tuesday, with the S&P 500 and Nasdaq extending gains

for a fourth straight session, buoyed by expectations that the

Federal Reserve will ease monetary policy this year.

The Dow Jones Industrial Average rose 6.7 points, or

0.02%, at the open to 38858.94. The S&P 500 rose 6.5

points, or 0.12%, at the open to 5187.2​, while the Nasdaq

Composite rose 9.1 points, or 0.06%, to 16358.343 at the

opening bell.