Danuiel Domscheit-Berg, a former spokesman for the site, told Spiegel Online that he destroyed the confidential data after he departed the organisation following a falling out with WikiLeaks leader Julian Assange.
He left the whistleblowing group towards the end of last year and is believed to have destroyed the data at the same time to avoid sources being compromised.
In a tweet, the website said: âWe can confirm that the DDB claimed destroyed data included five gigabytes from the Bank of America.â
Other information destroyed by Mr Domscheit-Berg is thought to include internal data on 20 neo-Nazi organisations and a copy of the entire US 'no-fly' list.
Mr Assange claimed he was in possession of a âmegaleakâ surrounding a major US financial institution in an interview during 2011 with Forbes magazine.
BofA was widely thought to be the institution in question although it was never officially confirmed.
By Jim Ottewill