All that money you've lost — did it even exist?

Trillions in stock market value — gone. Trillions in retirement savings — gone. ---It was never really money in the first place.

Robert Shiller, an economist at Yale, puts it bluntly: The notion that you lose a pile of money whenever the stock market tanks is a "fallacy." He says the price of a stock has never been the same thing as money — it's simply the "best guess" of what the stock is worth.

"It's in people's minds," Shiller explains. "We're just recording a measure of what people think the stock market is worth. What the people who are willing to trade today — who are very, very few people — are actually trading at. So we're just extrapolating that and thinking, well, maybe that's what everyone thinks it's worth."
Shiller uses the example of an appraiser who values a house at $350,000, a week after saying it was worth $400,000. "In a sense, $50,000 just disappeared when he said that," he said. "But it's all in the mind."

Though something, of course, is disappearing as markets and real estate values tumble. Even if a share of stock you own isn't a wad of bills in your wallet, even if the value of your home isn't something you can redeem at will, surely you can lose potential money — that is, the money that would be yours to spend if you sold your house or emptied out your mutual funds right now.

And if you're a few months away from retirement, or hoping to sell your house and buy a smaller one to help pay for your kid's college tuition, this "potential money" is something you're counting on to get by. For people who need cash and need it now, this is as real as money gets, whether or not it meets the technical definition of the word.

Still, you run into trouble when you think of that potential money as being the same thing as the cash in your purse or your checking account. There's a key distinction here: While the money in your pocket is unlikely to just vanish into thin air, the money you could have had, if only you'd sold your house or drained your stock-heavy mutual funds a year ago, most certainly can.

[Excerpt of an AP article by Eric Carvin]