What Wall Street shenanigans are giving investors fits this week? Dayana Yochim and Alison Southwick rip into Groupon (Nasdaq: GRPN) and its ongoing struggles with basic math, Best Buy's (NYSE: BBY) turnaround-plan blunders, and the mother of all marketing misunderstandings, courtesy of Kraft (NYSE: KFT).

As long as we're dissing stocks, we'd be remiss if we failed to mention one of the top companies that investors -- and consumers -- love to hate: Wal-Mart (NYSE: WMT). Who's to blame for the discounter's downfall? Motley Fool analysts have identified the biggest threats -- and the largest opportunities for investors -- in "The Death of Wal-Mart: The Real Cash Kings Changing the Face of Retail." Get this free report simply by clicking here.