US Steel (X) released its 1Q earnings on April 28 after the markets closed. It posted an adjusted loss of $0.07 per share. US Steel's results came in lower than analyst estimates, and its share price tanked more than 10%. AK Steel (AKS) also posted its results on the same day. Its share price rallied ~10% after its earnings release. Nucor (NUE), which posted its 1Q earnings on April 23, increased 2% after the earnings release, as its earnings were better than street estimates, as well as its own guidance. The company currently forms 2.6% of the Materials Select Sector SPDR ETF (XLB).