JPMorgan Chase, the largest bank in the United States, yesterday said that its loss from a highly publicised trading blunder had grown to $4.4 billion (€3.6 billion), more than double the bank’s original estimate of $2 billion.

The bank also said that it was reducing its net income for the first quarter by $459 million because it had discovered information that “raises questions about the integrity” of values placed on certain trades.

CEO Jamie Dimon said the bank had closed the division of the bank responsible for the bad trade and moved the remainder of the trading position under its investment banking division.

Overall, JPMorgan said it earned $5 billion, or $1.21 per share, for the second quarter, which covers April until June and includes the bank’s disclosure of the trading loss on May 10.

Analysts surveyed by FactSet, a provider of financial data, had expected JPMorgan to earn 76 cents per share. JPMorgan stock was down 49 cents, or 1.4 per cent, at $3.55 in pre-market trading.

Just three months ago, JPMorgan was viewed as the top American bank, guided by Mr Dimon’s steady hand. Since the disclosure of the trading loss, however, that reputation has been eroded.

Mr Dimon, who originally dismissed concerns about the bank’s trading as a “tempest in a teapot”, appeared before Congress twice to apologise and explain himself and several government agencies have launched investigations.

JPMorgan Chase said later top managers tied to the trading blunder have been dismissed without severance pay. The bank says it is taking back two years’ pay from them.

The bank is discussing the trading loss with Wall Street analysts.

Mr Dimon said: “We’re not making light of this error but we do think it’s an isolated event.”