On Wednesday, Pensions & Investments highlighted the top 10 performing blue-chip companies in the S&P 500 in 2012. Today, we examine the 10 worst-performing companies in the index. While the S&P 500 returned 15.9% in 2012, the bottom 10 performers posted an average total return of -41%. Education provider Apollo Group fared the worst, returning -61% for its shareholders, followed by AMD, Best Buy, J.C. Penney and Hewlett-Packard with returns of -56%, -47%, -43% and -43%, respectively.