The US accounting industry agreed Thursday to revamp rules that had required banks to quickly recognize losses from the housing slump and had been blamed by some for worsening the financial crisis.

The Financial Accounting Standards Board, which sets corporate accounting rules, voted to change the so-called "mark to market" accounting standard, a spokesman for the group said.

Controversy had been growing on the rules, also known as "fair value" standards, that require a quarterly markdown of assets that have fallen in value.

The rules had been tightened after a series of corporate scandals including at energy firm Enron, which used unrealistic figures to inflate its worth.

But some analysts say that by forcing banks to recognize losses immediately, the rules delivered a one-two punch to the system by requiring financial institutions to raise new capital to offset the loss, and squeezing a bank's ability to make new loans to boost economic activity.

US banks had been forced to write off over 800 billion dollars' worth of losses linked to the real estate meltdown in the past two years.

The change "should give a boost to profits of financial companies," said Ed Yardeni at Yardeni Research.

"More importantly, it should take the pressure off of them to raise funds to fill up black holes in their capital created by the original rule."

Critics have argued that because markets for mortgage-related securities have been frozen, banks should be able to hold the assets to allow them to recover without booking immediate losses.

Jon Ogg, analyst at 24/7 Wall Street, said the mark-to-market rule forced banks "to put up good capital in reserves to offset the new lower market value of bad assets."

"That in turns takes up capital that could be used for new loans, and as you have seen over the last year creates a situation where the banks have to raise additional capital from the market or go to Uncle Sam with hat in hand," he added.

"When the markets are shut off or illiquid, this can create the feared death-spiral for lending institutions."

The change would allow banks to hold some securities to give them more time to recover in conditions where financial markets are frozen, making it hard to find a true market price.

Some economists have excoriated "mark to market" as a cause of the crisis, pointing out past periods such as the 1980s Latin America debt crisis where banks would have been wiped out if they had to book losses instead of holding them to await recovery.