Credit card company American Express Co's quarterly profit more than doubled as customers spent more in the holiday season in the United States, its core market.

U.S. retail sales increased 3.8 percent in the 2013 holiday season, according to data released by the National Retail Federation on Tuesday.

The same day, the U.S. Commerce Department said retail sales including automobiles, gasoline stations and restaurants rose 1 percent from a year earlier in the October-December period. (http://r.reuters.com/syk96g)

American Express said worldwide spending on its cards rose 8 percent in the quarter ended December 31, the biggest jump in four quarters.

Net income rose to $1.31 billion, or $1.21 per share, in the fourth quarter from $637 million, or 56 cents per share, a year earlier.

Total revenue, net of interest expense, increased 5 percent to $8.55 billion. Revenue at the company's U.S. card services unit rose 8 percent in the quarter.

American Express earned $1.25 per share, excluding expenses related to merchant litigation settlements reached last month.

Analysts on average had expected the company to earn $1.26 per share on revenue of $8.54 billion, according to Thomson Reuters I/B/E/S.

U.S. regulators fined the company in December over deceptive and misleading practices in selling credit card add-on products, and forced it to repay a total of $59.5 million to duped customers.

American Express shares closed little changed at $87.78 on Thursday on the New York Stock Exchange. The stock rose slightly in trading after the bell.

(Reporting by Aman Shah in Bangalore; Editing by Kirti Pandey)