If the housing market is bottoming right now, it could be the perfect time to introduce a new ETF to track MacroShares. This from Bespoke:

"MacroShares has been working on developing an ETF that tracks this index for what seems like years now, and today they finally start trading. And yes, leverage is involved. UMM tracks 3 times the 10-City Median Home Price Index, while DMM tracks 3 times the inverse of the index. Whether you want to use these as a hedge for your own home or speculate on the direction of housing, these ETFs now allow you to do it."

It all sounds so neat and simple. But if we've learned one thing over the past year (besides not telling Lenny your credit card number), it's that things aren't always as they appear with ETFs. If it isn't contango risk with USO, it's compound madness with all the leveraged ETFs.

So what about here? I asked Roger, and he was kind enough to ping me this. 

"With housing products, you need to be right about 2 things: One, the direction of the index which prints monthly. Two what the market's expectation of the future will be. The literature tells you it will trade away from NAV.

"It is more important to be right about what the market expects than what the actual index does maybe anyway."

On the surface, it sounds a bit like a VIX product where you're gaming market expectations of volatility expectations in the future. Buy a November VIX contract, and you're betting on where traders in November expect the SPX's volatility to be 30 days hence.

Long story short: Tread carefully here. There could be massive confusion and accusations of manipulation the first time these pups move contra to they way they "should."