MasterCard Inc. (search) , the second-largest U.S. credit card association, Wednesday said it plans to go public, converting from an organization owned by 1,400 worldwide banks at a time when valuations for credit card stocks are soaring.

MasterCard said it will issue Class A common shares to public investors through an initial public offering (search), giving shareholders 49 percent of MasterCard's equity and 83 percent of its voting rights.

The current shareholders will retain a 41 percent equity stake through non-voting Class B stock as well as Class M stock entitling them to elect several directors.

A new MasterCard charitable foundation will be awarded remaining voting rights and Class A shares representing 10 percent of total equity.

MasterCard spokeswoman Sharon Gamsin declined to comment, saying the Securities and Exchange Commission (search) imposes a "quiet period" on companies filing for an IPO.

The transaction takes place as Purchase, New York-based MasterCard and larger rival Visa International (search) face increasing pressure from American Express (AXP) and Morgan Stanley's (MWD) Discover unit, which operate competing networks of merchants. The credit card industry is also undergoing another wave of consolidation.