A joke isn't funny if you have to explain it. Likewise, the longer spent qualifying a rule, the less workable it becomes. The Securities and Exchange Commission's report to Congress on mark-to-market accounting , mandated as part of the bail-out of the US financial system, runs to more than 250 pages of suggested tweaks, clarifications and post-hoc justifications. Meanwhile, Brussels is urging the International Accounting Standards Board, which sets the rules for most of the rest of the world, to come forward with technical solutions . On the basis of previous output, it will also be voluminous. Both it and FASBthe Financial Accounting Standards Board, its US counterpart, have issued "interpretative guidance" for aeons.

The blizzard of paper represents a failure of nerve. That is perhaps understandable, given the anguished howls of powerful bank chief executives who have seen their equity bases eaten away by silly investments. But the basic principle - mark balance sheet items at the price they would fetch in the open market, rather than what you paid for them - should be upheld. Wind back a few years, when firms were reporting sensational earnings: did anyone worry about fair value reporting then? Of course not. Pity the preparers of accounts, caught in the to and fro.