MasterCard Inc said second-quarter profit jumped 33 percent, as inflation in the United States lifted spending volume and more international consumers used debit and credit cards.

Shares rose as much as 10.9 percent.

The credit- and debit-card processor said signing up two big banks -- SunTrust Banks Inc and Banco Santander SA U.S. affiliate Sovereign Bank -- to offer MasterCard debit cards helped boost revenue in the second quarter, and should help next quarter too. The two banks had previously offered Visa Inc debit cards.

MasterCard executives told analysts on a conference call that the company benefited from overseas customers using debit and credit cards instead of cash to make payments, a long-term trend.

Spending over the MasterCard payments network also increased because of rising prices in the United States for gasoline and other goods, even though the broader economy has stayed sluggish.

U.S. economic weakness is now translating to slowing inflation or even deflation, which could cut into the dollar size of transactions that MasterCard processes in the coming quarters. But analysts said the company's expanding international business can offset any domestic slowdown.

They're getting strength from other areas, said Shannon Stemm, a financial services analyst with Edward Jones.

Purchase, New York-based MasterCard on Wednesday reported second-quarter net income of $608 million or $4.76 per share, up from $458 million, or $3.49 per share, a year earlier.

Analysts had expected $4.23 per share, according to Thomson Reuters I/B/E/S.

Visa also beat analysts' expectations when it reported quarterly results last week.

NEW FEE PLAN

MasterCard executives said they would alter their U.S. debit interchange fee structure in advance of new industry fee caps being imposed on those charges later this year.

The fees are charged to merchants for processing customers' debit card transactions. The so-called Durbin amendment to the 2010 Dodd-Frank financial reform law placed a cap on those fees which takes effect later this year.

MasterCard's U.S. market chief Chris McWilton said the company would institute a two-tiered fee structure by October 1, with fees varying according to the size of the merchant. McWilton did not comment on how the new system relates to the Durbin amendment, or how it would affect revenue.

Last week, Visa said it would introduce a flat network participation fee, and lowered the per-transaction rate for processing all U.S. transactions.

MasterCard's U.S. payment volumes were boosted by a spike in food and energy prices that fanned inflation earlier in the year, undercutting consumer spending and economic growth. But with gasoline prices off their peak of $4.02 a gallon in early May, inflation pressures are subsiding.

Consumer prices fell 0.2 percent in June, the largest drop in a year. Economists expect prices to moderate further in the months ahead amid sluggish demand.

MasterCard's revenue increased 22 percent to $1.7 billion as its cross-border and overseas business grew.

Overall, MasterCard's cross-border transactions rose 19.3 percent, and processed transactions increased 17.4 percent.

The company said it also gained from new processing business in the Netherlands and Brazil.

Total operating expenses increased 20 percent to $782 million. MasterCard said the rise was due to higher personnel costs related to acquisitions.

MasterCard shares were up 10.1 percent at $328.75 on Wednesday afternoon, off a new year-high hit earlier of $331.12.

(Reporting by Joe Rauch; Additional reporting by Lucia Mutikani in Washington; Editing by Gerald E. McCormick, John Wallace and Matthew Lewis)