New York - Wall Street stocks retreated on Monday ahead of a trove of key earnings reports and a closely-watched policy decision by the European Central Bank.
Analysts described investor sentiment as cautious ahead of upcoming results this week from Microsoft, McDonald's, United Continental and others.
Also, ECB chief Mario Draghi will be under pressure to clarify the bank's stimulus plans at a news conference on Thursday.
"The burden of proof lies with the bulls to demonstrate that the market can in fact move higher with all the various economic and political headwinds that we are currently facing," said Michael James, managing director of equity trading at Wedbush Securities.
The Dow Jones Industrial Average shed 0.3% to 18 086.40.
The broad-based S&P 500 fell 0.3% to 2 126.50, while the tech-rich Nasdaq Composite Index dropped 0.3% to 5,199.82.
Dow member Caterpillar lost 0.4% as it announced that chief executive Doug Oberhelman would step down to be replaced by Jim Umpleby, currently a group president overseeing energy and transportation. Oberhelman was behind Caterpillar's 2011 purchase of mining equipment maker Bucyrus just ahead of the prolonged slump in the mining and energy industries.
Toymaker Hasbro surged 7.4% as third-quarter earnings jumped 24.1% to $256.2m behind strong sales for fashion and dolls tied to Disney's "Princess" and "Frozen" franchises.
Mattel, another toy company, rose 0.3%.