US STOCKS-Materials, energy shares weigh on indexes
* Nike down after revenue misses estimates
* S&P 500 slips back to negative turf for 2016
* All three indexes down 2 pct (Updates to open)
By Abhiram Nandakumar
March 23 (Reuters) - U.S. stock indexes were slightly lower on Wednesday morning, dragged down by energy and materials stocks, as investors remained wary of taking on risk in a week marred by the attacks in Brussels and shortened by the Good Friday holiday.
Oil prices were lower after data showing a rise in U.S. stockpiles last week rekindled worries about a global glut. Gold and metals prices also fell as the dollar strengthened on hawkish comments from U.S. Federal Reserve policymakers.
The Dow Jones industrial average held onto meager gains for the year after a five-week rally helped the market recover from a steep selloff at the start of the year. The S&P 500 slipped back to negative territory for 2016.
"We've seen a tremendous run-up largely related to the fact that the world didn't end after all, but it is hard to see where we get the kind of improvement from here which would drive the market sustainably higher," said Brad McMillan, chief investment officer at Commonwealth Financial Network in Waltham, Massachusetts.
At 9:39 a.m. ET, the Dow Jones industrial average was down 35.16 points, or 0.2 percent, at 17,547.41, the S&P 500 was down 4.18 points, or 0.2 percent, at 2,045.62 and the Nasdaq Composite was down 9.62 points, or 0.2 percent, at 4,812.04. Continuación...