SAN FRANCISCO — Although much remains uncertain about the deal, which is subject to the vagaries of financial markets and legal settlements, credit unions that issue Visa cards stand to gain a possibly substantial financial windfall from Visa Inc's initial public offering of stock expected later this year.

The major card brand's IPO is the final step in its transformation from an association of financial institutions that issue Visa cards to an incorporated company able to raise money in the financial markets. As part of that move, the brand will issue stock to its financial institution issuers that could be worth tens of millions of dollars on the open market. But it will also use some of the stock, including stock from issuers, to settle long-standing legal claims from American Express and other organizations over the association's previous acceptance policies.

"It is a little bit like giving with one hand and taking back with the other," explained Steve Salzer, general counsel with PSCU Financial Services, the card and payment CUSO with more than 500 credit union members, most of whom process card transactions on First Data Corp's card platform. "But the end result should be additional assets on the bottom lines of credit unions around the country that issue Visa–we just don't know how big an asset or definitely what it will be worth."