Stocks were flat to slightly lower in thin trading on Monday a day before the presidential election as traders were reluctant to place bets until the winner of the very close race is known.

Shares of Apple rose, helping the Nasdaq composite index, after it announced brisk sales of its new iPads.

Democratic President Barack Obama and his challenger, Republican Mitt Romney, dashed through a handful of swing states, stumping for votes on the last day of the race for the White House.

Investors were also monitoring congressional races to gauge how the United States will deal with the $600 billion in spending cuts and tax hikes that could kick in next year and severely damage the economy.

On election eve traders waited before placing bets on sectors likely to benefit under the election's victor.

"In terms of the election, it is hard to predict ... how it is going to turn out and it's hard to predict how the market is going to respond to it," said Paul Mendelsohn, chief investment strategist at Windham Financial Services in Charlotte, Vermont.

"We are just going to drift between now and tomorrow and maybe Wednesday we can pick up some direction based on the election."

Leading world economies pressed the United States on Sunday to act decisively to avert the fiscal cliff, calling it the biggest short-term threat to global growth.

The market's reaction to data showing the pace of growth in the U.S. services sector slowed modestly in October was muted. Data from the Institute for Supply Management showed new orders slipped, but employment improved.

Market participants may also have to deal with interpreting economic data which could soon start to show the impact of Hurricane Sandy on the economy after battering the U.S. northeast.

A week after Sandy wreaked havoc on New York City and the surrounding area, close to 2 million people still have no power as cold weather sets in. On Sunday 30,000 to 40,000 people in New York City were in need of shelter.

The Dow Jones industrial average slipped 15.17 points, or 0.12 percent, at 13,077.99. The Standard & Poor's 500 Index shed 1.68 points, or 0.12 percent, at 1,412.52. The Nasdaq Composite Index added 4.86 points, or 0.16 percent, at 2,986.99.

Apple Inc rose 1.4 percent to $584.74 after the company said it had sold over 3 million of its new iPads over the first three days.

Transocean Ltd reported a higher-than-expected adjusted profit for the third quarter and its shares were up 4.7 percent at $48.23.

Stifel Financial Corp shares gained 1.6 percent to $32.42. KBW Inc climbed 7 percent to $17.44 after Stifel said it would buy the smaller rival in a cash-and-stock deal valued at about $575 million to form an investment bank focused on the financial services industry.

A private survey of China's growing services sector slipped in October, with weaker-than-expected new orders injecting a note of caution after three previous PMI surveys for October showed the world's second-largest economy regaining momentum.

The euro zone debt crisis also remained an issue for investors, as a senior European Union official said a deal to keep near-bankrupt Greece afloat by providing more bailout money is unlikely to be struck next week when euro zone finance ministers meet in Brussels.

(Reporting by Chuck Mikolajczak; Editing by Kenneth Barry)