Despite the volatility, October was a good month for stocks. The Standard & Poor’s 500 index gained 10.77%, which is the 23rd-best monthly advance since 1926, according to the S&P Indices Group. Over the past 40 years, only seven months have seen better gains.But not all stocks rose in price, and not a single major entertainment company was among the top 25 advancers in the index. In fact, the entertainment sector included some real clunkers. S&P reports that three entertainment industry biggies were among the 25 stocks in the index with the largest percentage declines in price last month. The slumps reflect company-specific problems that came to light during the release of quarterly earnings. But it’s worth noting that each of the firms is a big player in content distribution. Ranking 20th among last month’s decliners was Amazon.com, which slid 1.26% as expenses climbed faster than revenues. Its third-quarter earnings plunged 73% In seventh place was Cablevision Systems, which fell 8.01%. The company blamed costs associated with repairs from Hurricane Irene. And leading the pack was Netflix, which plunged a whopping 27.47%. Even though the company beat third-quarter earnings estimates, it guided lower for the fourth quarter.