May 20 (Reuters) - The main U.S. stock indexes were

almost flat at open on Monday, as investors awaited quarterly

results from Nvidia ( NVDA ) and the Federal Reserve's policy meeting

minutes due this week that will likely test Wall Street's

record-breaking run.

The Dow Jones Industrial Average fell 13.83 points,

or 0.03%, at the open to 39,989.76. The S&P 500 opened

higher by 2.08 points, or 0.04%, at 5,305.35, while the Nasdaq

Composite gained 16.06 points, or 0.10%, to 16,702.02 at

the opening bell.

(Reporting by Ankika Biswas in Bengaluru; Editing by Devika

Syamnath)