MasterCard Inc. (NYSE: MA) shares rose 12.3% to $335.13 after the payments-network reported second-quarter profit that topped market expectations. Volume for the stock crowded 4.3 million shares, better than four times its daily average.

A news release issued August 3 noted that the company reported net income of $608 million, up 32.8%, and earnings per diluted share of $4.76, up 36.4%, in each case versus the year-ago period.

Net revenue for the second quarter of 2011 was $1.7 billion, a 22.1% increase versus the same period in 2010. On a constant currency basis, net revenue increased 18.0%.

“Solid global performance, including strong increases in volume and processed transactions, fueled double-digit revenue growth this quarter,” said MasterCard CEO Ajay Banga in the same release. “While payment volumes have risen across our base customers, were also seeing new business such as the portfolio conversions of SunTrust and Sovereign, as well as new processing relationships in the Netherlands and in Brazil, contribute to growth.”

Banga added, “During the quarter, work continued in the mobile commerce category highlighted by an agreement with Google and multiple partners to launch the Google Wallet, as well as our alliance with Isis, in the U.S. Additionally, the previously announced Orange and Barclaycard contactless mobile payment service became available to U.K. consumers in May. Other notable agreements we executed include a commercial alliance with China Union Pay to enable its cards for cross-border e-Commerce, and a new, multi-product agreement with Swedbank in the Nordic and Baltic regions.”

MasterCard is a global payments and technology company. It operates the world’s fastest payments processing network, connecting consumers, financial institutions, merchants, governments and businesses in more than 210 countries and territories.