if the market tanks and I suspect it will, you have your money tied up until it rebounds. Where as what others says below you have equity you can pull from if needed. Additionally, unless you are going to invest in real estate ETFs (which yes comparing equity to investing is a stretch), you are putting all your eggs in one basket.

Tax implications, assuming 3-4% for home equity loan. Add in the taxes when you "sell", you better be hitting probably anywhere from 8-10% in the market to make significant enough money to make it worth it. Index funds average 7% over time, so you would have to pick some specific sector funds and/or individual stocks to make it worth it, imo.

Seem dubious and risky to me.

HokieForever