(Reuters) – U.S. stock index futures dipped on Monday as investors returned from their Easter break and took a cautious stance at the beginning of what is expected to be the busiest week of the first-quarter earnings season.

FILE PHOTO: A street sign for Wall Street hangs in front of the New York Stock Exchange May 8, 2013. REUTERS/Lucas Jackson

The S&P 500 closed slightly lower last week, ending its three-week winning streak, but hovered about 1% away from a record high hit in September on U.S.-China trade hopes and a largely upbeat earnings season.

More than a third of the S&P 500 companies, including Boeing Co, Amazon.com Inc and Facebook Inc, will report this week determining whether investors should be concerned about the start of