New York: US stocks reversed early gains to end mildly lower as big US companies are reporting their quarterly results this week. The Dow Jones Industrial Average fell 20.55 points, or 0.12 percent, to 17,556.41 on Monday, Xinhua news agency reported. The S&P 500 lost 5.61 points, or 0.27 percent, to 2,041.99. The Nasdaq Composite Index decreased 17.29 points, or 0.36 percent, to 4,833.40. US material company Alcoa, seen as an unofficial start to quarterly earnings season, will post results after the market closes. Big bank earnings, starting with JPMorgan Chase & Co on Wednesday, will be watched closely this week. Experts said that market expectations for profit growth are low amid the sluggish world economy, a strong dollar and declining commodity prices. According to Thomson Reuters, the blended earnings of the S&P 500 companies in the first quarter of 2016 are expected to decline 7.7 percent year on year, while the revenue is forecast to decrease 1.3 percent. Wall Street also kept a close eye on oil recovery. Oil prices extended gains on Monday, with US oil settling above $40 a barrel for the first time since March 22, as crude producer countries are scheduled to meet on Sunday in Doha to discuss the output freeze.