One of Wall Street's most-watched metrics surprised investors on Monday. Leading indicators rose by 1.2 percent in October, double the 0.6 percent increase expected by economists polled by Reuters.
In September, the index declined 0.2 percent, according to the Conference Board.
The index is a closely followed indicator for how strong the U.S. economy is. The Conference Board tracks 10 components, including manufacturers' new orders, stock prices and average weekly initial claims for unemployment insurance.
Elsewhere, U.S. investors remain on edge, as news surrounding tax reform continues to shake up markets.
Last Friday, the U.S. Treasury Secretary Steven Mnuchin told CNBC that he foresaw a Republican tax reform bill to be sent to President Donald Trump by the end of 2017.
Comments by Mnuchin were made a day after House Republicans passed a bill, that hopes to overhaul the tax code. Concerns, however, still linger on Wall Street, as to whether a deal will come about and be finalized by the end of the year.
—CNBC's Gina Francolla contributed to this report.