Well, I haven't walked through the math on a spreadsheet, but here is my gut reaction:
1) probably not a good thing to try right now unless you have lots of home equity and aren't worried about your home value dropping as we figure out what's going to be happening to the housing market. Even if you are in this situation, there are things to consider.
2) if you are taking out a new home equity loan, the transaction costs are likely to jack up your effective APR, so be sure to consider that. If you have a home equity line of credit, it is concievable that you could do this, but it still might not be a good idea.
3) true that the effective cost of the loan is (loan rate) * (1 - marginal tax rate), so if you are in at a 8% loan and in the 25% tax bracket, the after tax effective interest rate is about 6%. Be sure to compare this to your margin rates. I don't remember if the earlier post that went through the math included the tax effect - if so, it wasn't obvious to me.
4) I believe the IRS code does say somewhere that the tax writeoff for home equity or HELOC is for uses that substantially contribute to the maintenance of the property. It's a wierd part of the tax code, but in an audit, if they discover that you are using home equity to finance lots of other things, vacations, cars, etc.., they can theoretically charge you back taxes on that. (I'm not 100% sure of this, and how the details work, but I remember reading through some fine print once that mentioned this). Lots of people do it anyway, since it seems like a difficult thing to enforce.
5) leverage with home equity has the same risks as traditional margin leverage, with the one exception that you won't have to meet margin requirements. If you have true investment skill and can ride out large drops in your position, then using home equity could be an advantage. However, are you really sure you have that much skill? It's more likely that you will over-leverage because of this, which makes your bets riskier. So, if you are very confident in your investment skill, you might do this, but if I wanted to invest in you and you said you were going to do this, I would probably keep my money away from you.
Anyway, not promising to be the guru here, but these are my reactions. I'm happy to be corrected or ammended.
(I hadn't thought of SuperI's point about diversification - that makes a lot of sense. I wonder if there would be some kind of swap mechanism where someone can exchange their real estate risk for equity or other risk. I know they now have real estate futures in some markets, but that's just swapping one real estate risk for another real estate risk)
Edited 2 time(s). Last edit at Monday, September 11, 2006 at 10:33AM by bchadwick.