The current momentum should carry Walmart into the 13-figure club.For decades, Walmart (WMT 0.74%) has been a retail staple, with more than 10,000 stores across 19 countries. While retail remains its bread and butter, it's approaching the industry from a more modern direction, and it's been paying off for its business and stock.Through Dec. 14, Walmart's stock is up more than 29%, outperforming the S&P 500 and putting the company on a path to join the trillion-dollar market cap club.At the time of this writ ...