U.S. stock indices closed little changed on Monday as investors were cautious ahead of Thanksgiving Day on Thursday.

The Dow Jones Industrial Average fell 31.13 points, or 0.2%, to 17,792.68. The S&P 500 lost 2.58 points, or 0.1%, to 2,086.59 (six out of its 10 sectors declined). The Nasdaq Composite edged down 2.44 points, or less than 0.1%, to 5,102.48.

Pfizer (PFE) and Allergan (AGN) confirmed they will merge and become the largest pharmaceutical company in the world. The company would be worth around $160 billion. Pfizer stocks fell 2.9% and Allergan stocks lost 3.3% after the news.

This morning in Asia Hong Kong Hang Seng declined 0.84%, or 189.73, to 22,476.17. China Shanghai Composite Index lost 0.57%, or 20.63, to 3.589.68. The Nikkei gained 0.24%, or 47.06, to 19,926.87.

Asian indices traded mixed. Stocks outside Japan fell following declines in the U.S.

Favorable preliminary data helped Japanese stocks gain. The country's manufacturing PMI rose to 52.8 in November from 52.4 reported previously. Economists had expected a reading of 52.1.

Chinese stocks continued falling amid declines in copper prices.