Shares of Marathon Petroleum (MPC) have been struggling lately and have lost 14.4% over the past four weeks. However, a hammer chart pattern was formed in its last trading session, which could mean that the stock found support with bulls being able to counteract the bears. So, it could witness a trend reversal down the road.The formation of a hammer pattern is considered a technical indication of nearing a bottom with likely subsiding of selling pressure. But this is not the only factor that makes a bullish ...