Visa IPO Charges Ahead

But Menlow says that the big premium on the stock in such a large offering "makes people nervous."

"What now? Who is going to buy my stock if I decide to sell?" Menlow says. He adds his firm was "looking for a small premium" on Visa's first day of trading -- more like 5% to 8% rise in the stock, not 30%.

Of course, Visa isn't totally immune to a worsening economic environment. If consumer spending drops off significantly, Visa's revenue will suffer from fewer completed transactions, if consumers close up their purses.

Einhorn added in an email that Visa's stock will also be somewhat susceptible the markets. "[I]f the market goes down in the near future, that could drag Visa down with it -- that's probably one of the bigger concerns investors (and we) have right now," he said.

Shares of other credit card companies were mixed on Wednesday. After rising in the earlier part of the day, MasterCard shares closed down 1.2%, while American ExpressAXP and Capital OneCOF each fell nearly 4%. Shares of Discover Financial ServicesDFS slumped 12% after the company posted disappointing quarterly earnings.

Visa's IPO is the largest in U.S. history, surpassing AT&T Wireless Services' $11.2 billion debut in 2000, according to NYSE. It is the third largest of all time, following Industrial & Commercial Bank of China's $21.9 billion IPO in 2006 and NTT Mobile Communications Network's $18.4 billion debut in 1998.

GoogleGOOG raised about $1.9 billion in its first day of trading in 2004.