Billions of dollars were hidden by Citi and BofA over three years

As it has become unveiled, Bank of America and Citigroup incorrectly accounted for billions of dollars in debt over the past three years.

The report from the Wall Street Journal lightens a form of corporate borrowing to surge under scrutiny since the very beginning of the financial crisis. The loans, known as "repos," or short-term repurchase agreements, allow banks to increase the amount of risk they can take in securities trading.

Both BofA and Citigroup disclosed in filings with the SEC that they have over the last three years accidentally classified some repos as sales when they should have been classified as borrowings, the newspaper reported. Despite these amounts totaled billions, they appeared to be small for the banks.

Bank of America and Citigroup claim the accounting flaws were purely accidental and represent minute portions of their overall operations.

In addressing errors that made up to $10.7 billion per quarter Bank of America noted that the flaws represented substantially less than 1% of bank’s total assets.