Complex sentence: Soriana is a Wal-Mart-style chain of megastores, operating 500 grocery stores around Mexico, during the 2012 presidential elections, people who voted for el PRI, would receive pre-paid gift cards.
Split into simpler sentences: Soriana is a Wal-Mart-style chain of megastores, operating 500 grocery stores around Mexico. During the 2012 presidential elections, people who voted for el PRI would receive pre-paid gift cards.