Stocks opened flat Monday, after Caterpillar reversed declines after the global manufacturer posted higher-than-expected profit.

Caterpillar Inc. (CAT.N). the world's largest construction and mining equipment maker, cut its profit and revenue guidance, saying that global economic conditions were weaker than previously expected.

And on the international front, the euro edged higher as Spanish Prime Minister Mariano Rajoy was given a boost for his austerity drive with an election victory in his home region on Sunday.

The victory there gives the prime minister some breathing space after polls showing him losing support amid massive demonstrations against spending cuts in public services and successive tax hikes.