UPDATE 1-Data breach at TJX affected 94 mln accounts-suit

(Adds statement from TJX, stock price)

NEW YORK, Oct 25 (Reuters) - A data breach at TJX Cos. (TJX.N: Quote, Profile, Research) could have affected more than 94 million consumer accounts, or more than double what the retailer estimated previously, a group of banks asserted in court documents this week.

TJX, which operates more than 2,400 stores under names that include TJ Maxx, Marshalls and A.J. Wright, disclosed in March that data from 45.7 million credit and debit cards were stolen from its computers by hackers over 18 months.

Personal information from 451,000 customers who returned goods was also stolen in what was already the largest data breach ever.

But a group of banks suing TJX said in court filings that some 65 million Visa account numbers and 29 million MasterCard account numbers were affected by the breach, citing sealed testimony from officials at the two largest credit card issuers.

In an e-mailed statement, TJX said it "cannot account for the actions of banks and continues to stand behind the information it has previously disclosed regarding the data from 45.7 million card accounts."

The plaintiffs, which include the Massachusetts and Connecticut Bankers Associations, are suing Framingham, Massachusetts-based TJX for the costs associated with the breach and are seeking class-action status.

TJX last month said it had agreed to settle class-action suits filed by customers in the United States and Canada in connection with the breach. It had set aside second-quarter reserves of $107 million for potential losses.

In its statement, TJX said it "continues to believe that its reserve, recorded in its most recent second quarter, will cover all cash losses and costs resulting from all litigation related to the computer intrusion."