(Adds details, analyst comment)

NEW YORK, Dec 22 (Reuters) - Visa Inc (V.N: Quote, Profile, Research), the world's largest credit card network, said on Monday it set aside an additional $1.1 billion to cover legal expenses.

Before becoming a public company in March, Visa set aside $3 billion to cover lawsuits. It has already spent $2.1 billion in a settlement with American Express Co (AXP.N: Quote, Profile, Research) over anti-competitive practices, and in October it agreed to pay $1.89 billion to Discover Financial Services (DFS.N: Quote, Profile, Research) over the next year in a similar settlement.

Visa said the new addition to its litigation account had the effect of a $1.1 billion share repurchase. Under the terms of its initial public offering, Visa's bank shareholders agreed to have their stake diluted to fund litigation in order to save other shareholders from direct losses from lawsuits in certain U.S. court cases.

The transaction announced on Monday reduces share count by about 20.8 million and will boost 2009 operating earnings by about 7 cents a share, according to John Williams, an analyst at Macquarie Research.

Visa shares were up 9 cents to $55.06 in early trading on the New York Stock Exchange. (Reporting by Juan Lagorio, Editing by John Wallace)