U.S. markets opened higher on Monday on the back of positive earnings results from Citigroup and a slew of M&A deals. Wall Street appeared to like Citigroup's (C) quarterly results. Citi posted a profit much better than expected for its second quarter. The troubled bank also announced a $7 billion settlement with the U.S. Justice Department involving shoddy mortgage securities ahead of the 2008 financial crisis. JP Morgan (JPM), Goldman Sachs (GS), Bank of America (BAC) and Morgan Stanley (MS) are set to report earnings this week. Deals are also moving the markets today including one from Sotheby's (BID) and Ebay (EBAY). The two companies will partner to stream Sotheby's sales worldwide. TheStreet's Susannah Lee reports from New York.