[Via the comments.] You have to love the credit card industry. They remind me of that old story about the man who killed both his parents - and then threw himself on the mercy of the court because he was an orphan:

If you haven't had the credit limit cut on your credit card recently, count yourself lucky. Risk-averse card issuers are getting slash happy. And while many cardholders gripe that such cuts slice razor-close to their balance amounts, for an unfortunate few the cuts go far deeper: below what they currently owe.

Under different circumstances, David Chaplin-Loebell wouldn't have minded that American Express cut his unlimited credit line to just $5,000. Except that when AmEx reduced his line in October, he had an outstanding balance of $10,000. "I found out by having a business purchase declined," he says. Repeated calls to AmEx failed to yield an answer about why the cut was made. Chaplin-Loebell, who lives in Philadelphia, is now paying the balance under his regular card terms, and presumes the line will free up for new purchases once he's below the limit. "For now, they've essentially frozen the account," he says, leaving him to juggle business expenses on his personal cards. American Express did not respond to requests for comment.

Nasty as it may be, the practice of cutting credit lines below the balance is legal -- at least, for now, says Chi Chi Wu, a staff attorney for the National Consumer Law Center, a consumer advocacy group. Federal Reserve rules requiring lenders to give cardholders 45 days notice before reducing a credit line to the point that it would trigger penalties won't go into effect until July 2010. "[Until] then, there are no federal protections," says Wu.