Such business, barely profitable in the boom years, has become a gold mine as competition has dwindled and bid-ask spreads (the money dealers pocket on trades) have ballooned.

And like car dealers, we force you to borrow money to help make up the difference.

To help ease consumers' fears, G. M. could put money in escrow to reimburse its 6,468 dealers for any repairs to address problems covered by warranties.