Updated from 1:36 p.m. EDT

The Financial Accounting Standards Board voted Thursday in favor of a proposal that will give institutions more flexibility in how they use fair value, or mark-to-market, accounting rules, which have been blamed for exacerbating the financial crisis because it forced banks to record hefty writedowns on damaged assets.

Under the new guidelines, the FASB agreed that the objective of mark-to-market accounting still involves what would be received in an orderly transaction in a currently inactive market. However, the board said that an "orderly" transaction does not include a forced liquidation or distressed sale, which will allow assets to be valued differently.

The final vote in favor of softening the mark-to-market rules was unanimous. Meanwhile, a separate vote to finalize new accounting guidance related to how financial companies write down other than temporarily impaired assets passed 3 to 2.

The board also agreed to make the changes effective for the second quarter of 2009, although first-quarter applications will be permitted.

Financial stocks rallied on the news of the FASB's decision. Wells Fargo ( WFC) finished 5.9% higher for the day, Bank of America ( BAC) climbed 2.7%, Citigroup ( C) was up 2.2%, and JPMorgan Chase ( JPM) tacked on 0.3%.

The Argument for Accounting Changes

Many financial institutions have long complained about the regulation, FASB statement 157, which was implemented in 2007 to change the definition of fair value -- the measure of the worth of an asset on a company's books -- and the methods used to measure fair value.

The mark-to-market rules have led to assets being priced well below their real valuation to the current market value, making it impossible for banks to purge the toxic assets from their books at anything but deeply discounted prices.

Several organizations, including the American Bankers Association, urged the FASB to make changes to mark-to-market accounting, arguing that the rules for banking institutions often provide misleading information on financial statements.

Paul Mendelsohn, chief investment strategist with Hinsdale Associates, called the FASB's decision a "game changer." Last month, Mendelsohn wrote an opinion piece on why mark-to-market rules needed to be curbed.

"It's one of the pieces of the puzzle that got us into this catastrophe," he said. "There was a sequence of events that altered the whole regulatory structure. First, it was the repeal of Glass-Steagal, followed by the uptick rule and mark-to-market rule changes. Combined with the Securities and Exchange Commission approval to allow banks to lever up, we got us to this point in the crisis.

"However, mark-to-market was probably the largest component," Mendelsohn added. "You can see that because the crisis began after the writedowns came along with the mark-to-market rules."

Transparency Issues Linger

Others have said that mark-to-market rules have certain advantages, such as accurately revealing the extent of problem assets and the declining financial condition of institutions.

For instance, Cindy Fornelli, the executive director of the Center for Audit Quality, wrote in a letter to the FASB that by "ignoring relevant market transactions and moving to models in such a wholesale manner, transparency will suffer and the measurement results will no longer represent 'fair value' as defined by Statement 157."

The idea of transparency has led many to wonder whether banks will now mark assets up to unrealistic prices in order to appear healthier. However, Mendelsohn argues that bank regulators will ensure that banks won't run wild.

"Banks can't mark these to anywhere they want," Mendelsohn said. "They're regulated, and I'm sure their regulators are going to look at the methodology. It still falls under Sarbanes-Oxley. They need to come up with a reasonable model to price them."

Market participants also question whether the mark-to-market rule changes will now provide little incentive for banks to sell troubled assets to investors. Under the Obama administration's rescue plan for banks, a public-private partnership involving private investors, the Federal Reserve and the Federal Deposit Insurance Corp. will inject money into banks by taking these securities off their balance sheets.

The fear is that banks won't be willing to part with securities at bargain-basement prices and will instead hold the securities and mark them with a higher value, although Mendelsohn argues that the mark-to-market changes may ultimately help out taxpayers.

"If you can solve the problem without putting up taxpayer money, that's clearly a positive from the way one side looks at it," he said. "But the other factor is that Treasury Secretary Timothy Geithner was pumping capital and money into the system so banks would have more money to lend, and mark-to-market changes make that unlikely. But again, they're committing less taxpayer money and not putting it at risk."

More from Investing

Trump's 'Space Force' Could Launch a $1 Trillion Industry, Morgan Stanley Says

Trump's 'Space Force' Could Launch a $1 Trillion Industry, Morgan Stanley Says

Abiomed Stock Should Rise Some 12% From Here, Piper Jaffray Analyst Says

Abiomed Stock Should Rise Some 12% From Here, Piper Jaffray Analyst Says

Video: Here Is Why Carvana Isn't Worried About Amazon

Video: Here Is Why Carvana Isn't Worried About Amazon

Video: What Oprah's Content Partnership With Apple Means for the Rest of Tech

Video: What Oprah's Content Partnership With Apple Means for the Rest of Tech

REPLAY: Jim Cramer on the Markets, Oil, Starbucks, Tesla, Okta and Red Hat

REPLAY: Jim Cramer on the Markets, Oil, Starbucks, Tesla, Okta and Red Hat