Investors buy derivatives based on how much they think home prices will rise or fall in any of 10 metropolitan markets in the near term, up to five years.

But 19 months after it was launched with great expectations, only a small number of investors are taking advantage of it. About 20 contracts change hands a day, according to the C.M.E., and that volume hasn't grown in months. The buyers are mostly banks, funds, developers, and major property owners. Retail interest has been minimal.

Another real estate research firm, Radar Logic, began offering over-the-counter derivatives based on the housing markets in 25 cities in September. Only institutional investors can trade them.

Mary Haffenberg, the spokeswoman for the C.M.E., said she heard a lot more interest from prospective investors just after it launched trading of the Case/Shiller-based products, before the housing market began its steep decline. She says it's easier for people to invest in something they expect to go up, rather than shorting something they think will fall in value.

That’s behavioral finance, and it's a subject in which Robert Shiller, the co-founder of the Case-Shiller index, is well versed. A professor of economics at Yale University, Shiller predicted the bursting of the tech-stock bubble in his book Irrational Exuberance, published in 2000.

Shiller thinks that getting people to hedge against their real estate investments is a matter of education. Investors listen to their brokers, and their brokers are not yet advocating the practice. "It's a question of getting it recognized as a good thing to do," he says. "Most people don't sit down and think about how to hedge against their homes. They just listen to their investment advisers, who are slow to get the word out."

Despite the tentative start, Shiller still believes that the market for housing derivatives could one day be as big as the stock market. "I'm looking forward to the day when people watch home prices like they do the stock market," he says.

And for those of you who aren't watching, the futures market is predicting plenty more doom for housing. According to the latest data, the Miami market is to be the hardest hit, with prices falling 37.5 percent in the next five years. Investors forecast that the 10-city composite will be down 9 percent in the coming year and 15.2 percent in five years.

But what does Shiller think? "Those declines seem plausible to me," he says, before hesitating. "But I don't forecast officially."