2 April 2009: Accountants loosen mark-to-market and the Dow tops 8,000

Under heavy pressure from Congress and the banks, the Financial Accounting Standards Board voted on April 2, 2009 to give lenders more leeway in valuing toxic assets that no longer had a working market. Bank shares jumped and the Dow closed above 8,000 for the first time in weeks, part of the rebound from the March low. The assets were no better than the day before. Only the rules for describing them had changed.

The lesson: Changing how an asset is measured changes the headline, not the cash it will eventually produce.