MasterCard continues to ride the plastic wave in worldwide payments.

The Purchase, N.Y., company on Thursday reported fourth-quarter net income of $605 million, driven in large part by growing use of its credit and debit cards outside of the United States.

The company's earnings per share were $4.86, which exceeded by 6 cents consensus estimates of 33 analysts surveyed by Bloomberg. Earnings per share were up 21% from the fourth quarter of 2011, excluding a one-time charge a year ago.

MasterCard's (MA) quarterly revenue rose to $1.9 billion, or 10% higher than the same period a year earlier. That was due partly to 18% growth in the company's gross dollar volume internationally, versus 7% growth in the United States.

David Darst, an analyst with Guggenheim Securities, says the company's international growth is being driven by an ongoing conversion to electronic forms of payment that can overcome ups and downs in foreign economies. For example, if 6% of a particular country's payments convert to electronic payments each year, then even in a year when that country's consumer spending decreases by 2%, there's still likely to be revenue growth for MasterCard.

"The secular conversion from cash and check to electronic payments is a very solid trend," Darst says.

On a conference call with analysts, MasterCard executives sought to temper investor expectations for 2013, due particularly to short-term concerns about economic conditions.

The company stated that it expects net revenue growth in the first half of this year to be lower than it was in the second half of last year. It also noted that consumer confidence and spending were lower in the second half of 2012 in many parts of the world.

The economic concerns appear warranted, according to Moshe Orenbuch, an analyst at Credit Suisse. "It's kind of prudent to be cautious about America's outlook right now," he says.

But MasterCard executives expressed greater optimism about the longer-term U.S. economic outlook.

"I genuinely believe that over a period of a couple years, the U.S. has an opportunity to surprise people," Chief Executive Officer Ajay Banga told analysts. "I continue to believe that the U.S. has the potential to outperform over a three-year period."

Banga also said that new partnerships are allowing MasterCard to gain traction in the U.S. card business. Several U.S. banks — including Huntington Bancshares (HBAN) and, most recently, KeyCorp (KEY) — have recently announced credit card partnerships with MasterCard.

But in the fourth quarter of 2012, the company reported that its gross dollar volume in the U.S. credit card market was up just 3% from the same period a year ago. For comparison, MasterCard's gross dollar credit card volume in other parts of the globe was up 14%.

International markets make up 60% of MasterCard's revenue, with 67% of the company's growth in gross dollar volume happening outside of the United States, according to a company presentation to investors in September.

Banga, who just returned home from a business trip to Africa, was effusive about MasterCard's opportunities in countries such as Nigeria, South Africa and Myanmar. At the same time, he acknowledged some of the challenges of expanding in less-developed countries, saying that it must be done with care for the local governments.

Analysts asked Banga about a number of potential bumps in the road for MasterCard.

One question concerned the coming conversion in the United States from magnetic stripe cards to chip-and-PIN technology, known as EMV.

Other parts of the world are well ahead of the United States in making the switch, and Banga said that MasterCard's experiences elsewhere suggest that the U.S. conversion will not significantly hurt his company's bottom line.

"We do not expect a material impact to our economics, just because that hasn't happened elsewhere," he said. Another question involved the potential for new restrictions on interchange fees in Europe.

Referring to the European officials, Banga said, "You know better than I do that they love passing regulations," drawing laughs from analysts on the call.

"Will they pass legislation? Yes," he continued. "Will that dramatically change the industry? I don't know."

But any new restrictions on European interchange fees will hurt card-issuing banks rather than card networks such as MasterCard, according to Darst.

"You have to remember that MasterCard doesn't necessarily make their money on the interchange," he says.

Following the earnings report, MasterCard's stock price was largely unchanged in midday trading.

"The company's 4Q results were decent," Thomas McCrohan, an analyst with Janney Montgomery Scott, said in a research note.

McCrohan did not change his estimate of the fair value of the company's stock, noting that MasterCard management did not alter its objectives for revenue and earnings over the next three years.