Why foreign oil firms should look at Mexico By: MarketWatch August 23, 2013 at 09:49 AM EDT Mexico plans to open up its energy sector to foreign investment and investors will be intently watching the nation’s progress in that market for years to come. Read More >> Related Stocks: BP Plc ADR Chevron Corp China Petroleum & Chemical Corp ADR Ecopetrol S.A. ADR Exxon Mobil Halliburton Co