April 12 (Reuters) - Wall Street's main indexes opened

lower on Friday as most megacap growth stocks and chipmakers

receded, while some big banks dipped after dour quarterly

results.

The Dow Jones Industrial Average fell 139.94 points,

or 0.36%, at the open to 38,319.14.

The S&P 500 opened lower by 27.55 points, or 0.53%,

at 5,171.51, while the Nasdaq Composite dropped 149.17

points, or 0.91%, to 16,293.03 at the opening bell.