Visa on May 15th named Mr. Saunders, 61, as the first chief executive and chairman of what will eventually be known as Visa Inc. when it goes public early next year. Saunders, a former high-ranking executive at a number of large credit-card issuers, is best known for overseeing a big turnaround at Providian Financial Corp. about five years ago.

Mr. Saunders will be taking the post at a time of enormous change in the payments industry. Not only are consumers and businesses increasingly using credit and debit cards instead of traditional cash and checks, but the industry is also trying to pump up transaction volume by finding new ways to pay -- from making payments on a cellular telephone to speeding through a check-out line by waving a card at an electronic reader.

"Visa isn't a broken company, but we have to focus on how the industry is changing and what we need to do to remain at the forefront of that change," Mr. Saunders said.

Visa International rang up $4.6 trillion in transactions last year, up 14% from 2005. By comparison, MasterCard Inc. booked about $2 trillion. Debit and prepaid cards now account for 60% of Visa's global total consumer volume and more than 67% of the number of transactions.

Although Visa is far bigger than MasterCard, it has lagged behind its chief rival in structural change. MasterCard, based in Purchase, N.Y., went public a year ago in an initial public offering that surpassed expectations. Separately, Morgan Stanley is planning to spin off its Discover payment network into a stand-alone company this year.

Visa announced its IPO plans in October, but the process was expected to take as long as 18 months because it has to unravel its unusual structure. The new company will include all of its geographical units except for Europe, which will operate as a minority stockholder in the larger company.

Many details about Visa's IPO still aren't known because the company hasn't yet filed a prospectus with the Securities and Exchange Commission. At the time the plan was announced, some analysts estimated that Visa might have a market value of about $15 billion, but that figure is likely to be far higher now because of a run-up in MasterCard's share price. MasterCard, which went public last May at $39 a share, is trading at more than $135 a share, giving it a market value of more than $18 billion.

Visa and MasterCard are essentially processors of electronic transactions. They don't issue cards, set interest rates or accept payments from cardholders. Indeed, they don't have any direct relationship with consumers. Their customers are the financial institutions that issue the cards. Visa and MasterCard charge the banks to process their card transactions and brand the cards that the banks issue to cardholders.

Visa and MasterCard also set the fees that banks charge to merchants for accepting and processing card transactions. Merchants have sued the payment networks and the banks over those fees, charging them with colluding to set the rates. The financial institutions have denied that the fees are anticompetitive.

Before being named as Visa's executive chairman in February, Mr. Saunders ran the card business of Washington Mutual Inc., having joined the Seattle bank when it acquired Providian in 2005. Mr. Saunders was hired as the chief executive of Providian in 2001 after the big card issuer ran into problems after borrowers with spotty credit histories defaulted on loans. He turned around Providian by slashing costs and selling some assets, ultimately selling it to WaMu for more than $6 billion.

"I've got a pretty clear understanding of the path that is in front of us," Mr. Saunders said.

The choice may surprise some industry insiders who had thought Visa might tap a leader from the technology industry since electronic payments are increasingly becoming more sophisticated and complex.

Mr. Saunders's appointment will overshadow the role of John Coghlan, who was hired two years ago as chief executive of Visa USA Inc., Visa's biggest unit. Mr. Coghlan said in a statement yesterday that he intends to remain at the company.