Underwriters of the share offering of credit card payments group Visa exercised an option for another 40.6 million shares, boosting the record IPO to $19.1 billion, the company said Thursday. Visa Inc., which operates the world's biggest credit card network, saw its newly minted shares soar in value Wednesday by some 22 percent to end at $56.50 after the initial public offering. The company said the underwriters had taken the option to buy the over-allotment at the offering price of $44 per share. That will provide Visa with a total of 19.1 billion, up from the earlier estimated proceeds of 17.9 billion. Shares in the San Francisco-based firm, which processes credit card payments and fees around the globe, began trading under the stock ticker symbol “V.” Visa launched its gargantuan IPO as major Wall Street banks and brokerages weather one of the worst financial market downturns in decades. The offering was underwritten by JPMorgan Chase, Goldman Sachs, Banc of America Securities, Citibank, HSBC, Merrill Lynch, UBS and Wachovia Securities. Visa's giant IPO easily smashed the US record of $10.6 billion set by AT&T Wireless in 2000. The record for the world's largest share debut is held by The Industrial and Commercial Bank of China which debuted with a $21.9 billion IPO on Shanghai and Hong Kong markets in October 2006. __