Europe is biggest threat to corporate earnings

Corporate earnings have enjoyed double-digit growth for eight straight quarters, but that euphoric run may be coming to an end, thanks to Europe's worsening debt crisis and a tepid U.S. economy.

In fact, for every one company in the S&P 500 that has issued a positive outlook for the fourth quarter, 3.5 have been pessimistic, according to earnings tracker Thomson Reuters. 

That's the highest since the second quarter of 2001, and well above the historic average of 2.3.

"Companies always tend to under promise, but we are hearing a more genuine concern [and] Europe is a big factor," said Greg Harrison, corporate earnings research analyst at Thomson Reuters.

It's been about 18 months since Europe's debt problems intensified into a full-blown crisis. Greece is still not out of the woods, and worries about a deepening contagion into larger eurozone economies, such as Italy, have convinced economists that Europe is on the brink of a recession. Read more at CNN Money