Two of the best stocks in the universe this year have been MasterCard (MA) and Visa (V). MasterCard went public in May 2006 and has rocketed from its offering price, $39 a share, to $231. That's a six-fold increase. Visa, which scored the biggest IPO in history last March, has seen its stock rise from $44 to $73.

Ironic, isn't it, that these two companies are sailing along when so many U.S. consumers are in credit hell? Meanwhile, the big banks are reeling from lending money to too many deadbeats. MasterCard and Visa make money by processing payments, not extending credit. And since millions of people around the world are replacing cash with credit cards, these companies' profits are expanding dramatically, with minimal risk from the multiplying credit crises.

On Tuesday I had lunch with some MasterCard folks at Michael's in midtown Manhattan (and paid with my American Express (AXP) corporate card, sorry to say). We talked about the global migration from cash to credit -- about Asian and Middle Eastern consumers snapping up elite MasterCards studded with diamonds and, more darkly, desperate debtors in Turkey and Korea committing suicide. (The New York Times ran a front-page story on Sunday about this.)

We also talked about what may be the most exciting trend: mobile payments. MasterCard has experimented for years, largely abroad, with "contactless payments" via mobile phones. This year, MasterCard partnered with U.S. Bank and Nokia (NOK) for a pilot program in Spokane, Washington. If you live in New York, next year you'll likely be able to stand in front of a movie theater, tap your cell phone on the poster of the movie you want to see, pay for your ticket, and even buy your popcorn.

Even as MasterCard's stock has multiplied, there's room for more gains, many analysts say. Morgan Stanley (MS) put a price target of $320 on the stock and forecasts double-digit organic revenue growth, operating margins in the 30-40% range, and net income gains of more than 20% annually over the next three years.

Of course, as MasterCard and Visa clean up from consumers borrowing aggressively, there's ever more risk for the banks who put up the money. Byron Wein, a Morgan Stanley alum who is now chief investment strategist at Pequot Capital Management, warned in a Morgan Stanley report last month: "There is too much credit card debt. Holders of credit cards should have to put up a deposit before they can use their cards, like the renter of an apartment puts up security. No credit card borrowing should be allowed. Naturally that would cut consumption way down, but that is what is needed."

Wise words, but as we know, sanity doesn't drive businesses or markets either.