With some of Wall Street's most volatile names on the earnings calendar next week, investors may want to keep the antacids handy.

More positive U.S. earnings are expected, but investors are less certain how much of a boost the stock market might get from good results after a slump in the shares of Google Inc and others late this week.

Several companies reporting results in the coming week are traditionally among the most volatile after they release quarterly numbers, according to Bespoke Investment Group of Harrison, New York.

A prime example: The stock of flash memory card maker SanDisk Corp. , which reports after the close on Wednesday, tends to rise or fall more than 12 percent the day after earnings.

Shares of online merchant Amazon.com , due out Thursday afternoon, sport an average move of 11.3 percent after posting results, Bespoke said.

Other volatile names include Internet company Yahoo and DeVry , an online university.

What's more, estimates have been rising, with first-quarter earnings now seen increasing 39 percent from a year ago, up from an estimate of a 36.6 percent increase on April 1, according to Thomson Reuters data.

Expectations are sky high ... people are looking at this and saying, 'No doubt, the market has too high expectations,' said Burt White, managing director and chief investment officer of LPL Financial in Boston.

GOOGLE AND GOLDMAN

This week, the performance of stocks after companies release results has been uneven, at best.

On Wednesday, the Standard & Poor's 500 Index <.SPX> closed above 1,200 for the first time since September 2008 when Lehman Brothers collapsed. The S&P's jump above that 1,200 milestone followed strong results from Intel Corp , CSX Corp and JPMorgan Chase & Co , among others.

But the response following bellwether results later in the week was not as strong. Shares of Google, which reported quarterly results that beat forecasts after Thursday's closing bell, fell 7.6 percent on Friday to end at $550.15 on Nasdaq.

On Friday, Bank of America's stock dropped even though it posted its first quarterly profit since the summer of 2009. [ID:nN16232262] The stock fell 5.5 percent to close on Friday at $18.41 on the New York Stock Exchange.

News on Friday that Goldman Sachs was charged with fraud by the U.S. Securities and Exchange Commission is also very likely to overshadow earnings next week. Goldman is scheduled to report results on Tuesday.

Of the 48 companies in the S&P 500 that have reported earnings so far, 83 percent have beaten expectations -- well ahead of the 61 percent in a typical quarter, said John Butters, director of U.S. earnings for Thomson Reuters.

The high percentage follows the trend of recent earnings periods, with 70 percent or more S&P 500 companies beating estimates.

Next week, 123 S&P companies are expected to report quarterly results, including International Business Machines , Apple , Coca-Cola , Boeing , Microsoft and AT&T .

(Reporting by Caroline Valetkevitch; Additional reporting by Chuck Mikolajczak; Editing by Jan Paschal)

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