The materials sector, which tends to be the most sensitive to global economic growth expectations, has been performing well this year, given a resilient U.S. economy. The popular ETFs — Materials Select Sector SPDR (XLB) , Vanguard Materials ETF (VAW) , iShares U.S. Basic Materials ETF (IYM) and Fidelity MSCI Materials Index ETF (FMAT) — have gained 1.7%, 1.8%, 0.6% and 1.8%, respectively, over the past three months.Going into the Q2 earnings season, earnings releases from the sector giants will determine t ...