US companies give investors more reasons to cheer; surprisingly strong quarterly numbers

So far, second-quarter earnings have been like Christmas in July on Wall Street.

Over the last week 38 companies on the S&P 500 index have reported second-quarter results and S&P Capital IQ says most have posted bigger-than-expected profits. The market has responded, sending what has been a lackluster index up 3 percent since last Thursday's close, when the earnings season kicked off.

U.S markets have been trading around all-time highs but had slumped in recent months on doubts about domestic economic activity and problems abroad.

But then major U.S. corporations began to tip their hands, led by JPMorgan Chase & Co., Bank of America Corp. and Citigroup Inc. Netflix Inc. told investors it's had huge subscriber growth and UnitedHealth Group Inc. upped its outlook, again, after topping expectations.