Dec 30 (Reuters) - U.S. main stock indexes opened lower

open on Monday, as sparse trading volumes and the specter of

rising Treasury yields cast a cloud over the traditionally

strong year-end rally for equities.

The Dow Jones Industrial Average fell 128.3 points,

or 0.30%, at the open to 42,863.86. The S&P 500 fell 50.2

points, or 0.84%, at the open to 5,920.67​, while the Nasdaq

Composite dropped 261.6 points, or 1.33%, to 19,460.413

at the opening bell.

(Reporting by Johann M Cherian in Bengaluru; Editing by Devika

Syamnath)