NEW YORK (REUTERS, BLOOMBERG) - Wall Street opened little changed on Friday, coming off six straight days of gains, as investors took to the sidelines ahead of a three-day holiday weekend.

The Dow Jones Industrial Average dipped 8.56 points, or 0.04 per cent, to 21,074.39. The S&P 500 edged lower by 1.38 points, or 0.05 per cent, to 2,413.69. The Nasdaq Composite eked out a gain of 1.64 points, or 0.03 per cent, to 6,206.90.

US dollar fluctuated with oil as investors assessed fresh data showing the US economy on firm footing.

The S&P 500 pared its weekly gain, with carmakers slumping after President Donald Trump chided German producers for contributing to a lopsided trade surplus with the US.

Crude headed for a weekly loss after Opec's move to prolong supply cuts for nine months disappointed investors hoping for more.

Action was subdued ahead of a three-day weekends in the U.S. and the U.K. A second straight month of stagnant orders for business equipment in April indicated investment in capital goods could slow in the second quarter, paring weekly gains in US stocks.

"Markets ultimately found the renewed deal among OPEC and friends underwhelming," Cole Akeson, a strategist at Sberbank CIB in Moscow, wrote in an emailed note. "Essentially, the market consensus seems to have come around to a view that regardless of what effect on global inventories the deal may have for now, OPEC and its partners have little insight as to what to do later on." Read our Markets Live blog here.