Subject: Re: Volatility index "investing"
There are none, you can't buy (or sell) volatility via an ETF, or otherwise.

There are funds that employ VIX futures, e.g. VXX, but that's entirely different than VIX and if you look at the charts you can see how different.

The main reason for the blanket statement above is that volatility is a reading like "outdoor temperature" and is not something that can be bought or sold as you can soybeans, pork bellies, stocks etc. Therefore, the arbitrage argument that determines a 'fair price' for futures on soybeans, pork bellies, stocks etc doesn't work for VIX futures. It's the wild west out there. Buyer beware.

Maybe there's some ETF doing cash secured put selling. But trusting someone else to choose the underlyings and to trade derivatives for you is in general a bad idea, because buried somewhere in the prospectus will be the words "at manager's discretion".