(Reuters) -Wall Street's main indexes opened lower on Friday, and were set for sharp weekly declines, as concerns about the economy and towering valuations in the technology sector soured sentiment.

The Dow Jones Industrial Average fell 115.3 points, or 0.25%, at the open to 46,797.03. The S&P 500 fell 24.1 points, or 0.36%, at the open to 6,696.18​, while the Nasdaq Composite dropped 161.1 points, or 0.70%, to 22,892.917 at the opening bell.