The Standard & Poor's 500 and Nasdaq indexes edged up on Wednesday with investors responding positively to early earnings results as the quarterly reporting period got under way.

The mild moves follow two days of strong gains for the market, helped by optimism about third-quarter profits.

After the close, stock futures edged higher as aluminum company Alcoa Inc released its results, marking the onset of major earnings announcements. Shares jumped 5.8 percent to $15.02 in after-hours trade.

During the regular session, Costco Wholesale Corp rose 1.9 percent to $59 after the retailer posted profits that topped forecasts.

Expectations for the quarter have been high following the second quarter's strong showing, where more than 70 percent of companies beat Wall Street's consensus estimates.

The market has given earnings the benefit of the doubt and moved up in anticipation of continued improvement, said Keith Hembre, chief economist at First American Funds in Minneapolis. Expectations have become quite robust lately.

The Dow Jones industrial average <.DJI> was down 5.67 points, or 0.06 percent, at 9,725.58. The Standard & Poor's 500 Index <.SPX> was up 2.86 points, or 0.27 percent, at 1,057.58. The Nasdaq Composite Index <.IXIC> was up 6.76 points, or 0.32 percent, at 2,110.33.

Stocks also responded well to a successful 10-year Treasury note auction, which boosted confidence in U.S. assets, including stocks and bonds.

Alan Lancz, president of Alan B. Lancz & Associates investment advisers in Toledo, Ohio, said of the auction: It's a positive, as long as interest rates stay low and ...there's demand overseas.

On the Nasdaq, Verisk Analytics Inc surged 23.7 percent to $27.22 in its trading debut on Wednesday, a day after it raised $1.88 billion in the biggest initial public offering by a U.S. company since March 2008.

Google Inc was among Nasdaq's top performers, up 3.8 percent at $517.82 after the company's chief executive said the worst of the advertising recession was over.

Declining shares included telecommunications companies. The Federal Communications Commission chairman praised moves by top wireless companies to open their networks, and the S&P telecom services index <.GSPL> slid 2.9 percent.

Shares of seed developer Monsanto Co also fell, 1.4 percent to $74.33, after it reported a fourth-quarter loss that widened from the prior year.

Volume was below average on the New York Stock Exchange, with 1.09 billion shares changing hands, less than last year's estimated daily average of 1.49 billion. On the Nasdaq, about 2.23 billion shares traded, about even with last year's daily average of 2.28 billion.

Advancing stocks outnumbered declining ones on the NYSE by a ratio of 15 to 13, while declining stocks were about even with advancers on the Nasdaq.

(Additional reporting by Ryan Vlastelica; Editing by Padraic Cassidy)