July 31 (Reuters) - The Nasdaq and the S&P 500 opened

sharply higher on Wednesday after a bullish forecast from AMD

boosted struggling chip stocks, while Microsoft faltered among

megacaps ahead of an interest-rate decision from the Federal

Reserve.

The Dow Jones Industrial Average rose 25.5 points, or

0.06%, at the open to 40,768.88. The S&P 500 rose 69.2

points, or 1.27%, at the open to 5,505.59​, while the Nasdaq

Composite rose 351.8 points, or 2.05%, to 17,499.231 at

the opening bell.