* First-quarter earnings of $1.33/share vs est $1.30
* Revenue up 4 percent to $8.20 billion
* Operating expenses fall 4 percent
* U.S. billed business growth hurt by severe winter (Adds details from conference call, analyst comments, updates shares)
By Aman Shah
April 16 (Reuters) - American Express Co's quarterly profit beat analysts' average estimate as a tighter control on expenses helped make up for slower growth in consumer spending in its key U.S. market.
The world's biggest credit card issuer said an unusually severe winter caused billed business in the United States to rise 6 percent in the first quarter, lower than the 9 percent growth in the preceding quarter.
However, Chief Financial Officer Jeff Campbell said on a post-earnings conference call that the business had grown through the second half of the quarter as the weather improved.
U.S. retail sales increased 1.1 percent in March - the biggest gain since September 2012 - in a sign that the economy is bouncing back after the severe winter.
"While consumers remain cautious about taking on additional debt, we continued to see a modest increase in card member loan balances" CEO Kenneth Chenault said in a statement.
For a graphic on the company's U.S. billed business growth over the past four years, click (link.reuters.com/dyx58v)
American Express, which issues its own cards unlike rivals such as Visa Inc and Mastercard Inc, benefits from its largely affluent customers' consistent spending and low default rates.
The company's focus on affluent consumers should help drive growth as such customers in the United States spend 6 times more on their cards, Janney Capital Markets analyst Sameer Gokhale wrote in a note in February.
The United States accounts for about two-thirds of American Express's total billed business.
The company's net income rose 12 percent to $1.43 billion, or $1.33 per share, for the quarter ended March 31, beating the average analyst estimate of $1.30 per share, according to Thomson Reuters I/B/E/S.
Total revenue, net of interest expense, rose 4 percent to $8.20 billion but fell short of Wall Street expectations of $8.36 billion.
Overall spending by the company's card users rose 7 percent, adjusted for foreign currency, while consolidated expenses fell by 1 percent to $5.5 billion.
"They (American Express) have been trying to control expenses quite a bit and the run rate of expenses is below what we've seen in quite a few quarters," Gokhale said.
American Express in March spun off half of its business travel division into a joint venture with four financial investors as companies cut their budgets to protect profit margins.
CFO Campbell said that while the company still expects the deal to close in the second quarter, delays in getting approvals could push back this quarter's earnings release.
The company had said it would increase its quarterly dividend by 13 percent to 26 cents per share and buy back up to $4.4 billion of stock in 2014 after it passed the Federal Reserve's annual stress test in March.
The company's shares were unchanged at $87.40 in extended trading on Wednesday. They have risen 35 percent in the past year, outperforming the Dow's 11 percent gain. (Reporting by Aman Shah in Bangalore; Editing by Sriraj Kalluvila and Simon Jennings)