Amazon, Yahoo! Are S&P Gainers

NEW YORK (TheStreet) -- Shares of Amazon(AMZN) and Yahoo!(YHOO) were among the best performers on the S&P 500 midday Friday.

The S&P 500 fell 10.71 points to 1,341.24.

Shares of Amazon rose 1.06% to $186.94. The competition between rival tablet maker Apple(AAPL) and Amazon is getting more heated. Pacific Crest analyst Chad Bartley said in a research note this week that Amazon could launch a 9-inch Kindle Fire by the middle of 2012 to help it better compete with Apple's iPad.

Amazon has an estimated price-to-earnings ratio for next year of 46.43; the average for broad-line retailers is 27.67. For comparison, Wal-Mart(WMT) and Costco(COST) both have lower forward P/Es of 12.53 and 19.21, respectively.

Twenty-four of the 40 analysts who cover Amazon rated it a buy. Fifteen analysts gave the stock a hold rating and one considered it a sell. Shares of Amazon have risen 7.61% year to date.