U. S. regulators have said that a Minnesota bank has agreed to pay a $700,000 fine for losing millions of e-mails it is required to keep.

The Minneapolis Star Tribune reported on Tuesday that the Financial Industry Regulatory Authority said the failure of Piper Jaffray & Co. to store the e-mails could affect the investigation of a former bank employee.

Moreover, it is the second time the bank has dropped the ball on retaining e-mails. In 2002, the bank was fined $1.65 million for failing to store three years of e-mails.

The bank, at the time, said it would upgrade its software to ensure e-mails would not be lost.

The current problem was "inadvertent and isolated … caused by technology issues," the bank said on Monday

The regulatory authority, however, said that the bank had lost 4.3 million emails and had failed to report the problem to FINRA, the National Association of Securities Dealers or the New York Stock Exchange. (With Inputs from Agencies)