Volatility ETNs

While the CBOE Market Volatility Index (VIX) is closely tracked by many investors as a proxy of investors' expectations for the market, it's impossible to trade the VIX itself. The volatility index is just a statistic, and there are no shares to buy or sell. However, investors can circumvent this minor inconvenience by trading any one of a number of VIX-based exchange-traded notes, better known as volatility ETNs.

Here's a quick guide to some of the most widely known volatility ETNs.

iPath S&P 500 VIX Short-Term Futures ETN (VXX)

"The Index is designed to provide access to equity market volatility through CBOE Volatility Index^® (the "VIX Index") futures. The Index offers exposure to a daily rolling long position in the first and second month VIX futures contracts and reflects market participants’ views of the future direction of the VIX index at the time of expiration of the VIX futures contracts comprising the Index."

-- Courtesy of iPathETN.com

iPath S&P 500 VIX Mid-Term Futures ETN (VXZ)

"The Index is designed to provide access to equity market volatility through CBOE Volatility Index^® (the "VIX Index") futures. The Index offers exposure to a daily rolling long position in the fourth, fifth, sixth and seventh month VIX futures contracts and reflects market participants’ views of the future direction of the VIX index at the time of expiration of the VIX futures contracts comprising the Index."

-- Courtesy of iPathETN.com

iPath S&P 500 Dynamic VIX ETN (XVZ)

"The Index is designed to dynamically allocate between the S&P 500^® VIX Short-Term Futures^TM Index Excess Return and the S&P 500^® VIX Mid-Term Futures^TM Index Excess Return by monitoring the relative implied volatility of the SP 500^® Index at various points along the volatility forward curve. The Index seeks to react positively to overall increases in market volatility and aims to lower the roll cost of investments linked to future implied volatility. Roll cost (yield) refers to the loss (gain) in value of volatility futures over time, as contracts with a shorter time to expiry tend to be relatively cheaper than contracts with a longer time to expiry."

-- Courtesy of iPathETN.com

VelocityShares Daily Long VIX Short-Term ETN (VIIX)

"The investment seeks to replicate, net of expenses, the return of the daily performance of the S&P 500 VIX Short-Term Futures index.The index was designed to provide investors with exposure to one or more maturities of futures contracts on the VIX, which reflects implied volatility of the S&P 500 Index at various points along the volatility forward curve."

-- Courtesy of Yahoo! Finance

VelocityShares Daily Inverse VIX Short-Term ETN (XIV)

"The investment seeks to replicate, net of expenses, the inverse of the daily performance of the S&P 500 VIX Short-Term Futures index. The index was designed to provide investors with exposure to one or more maturities of futures contracts on the VIX, which reflects implied volatility of the S&P 500 Index at various points along the volatility forward curve."

-- Courtesy of Yahoo! Finance

VelocityShares Daily 2X VIX Short-Term ETN (TVIX)

"The investment seeks to replicate, net of expenses, the returns of twice (2x) the daily performance of the S&P 500 VIX Short-Term Futures index. The index was designed to provide investors with exposure to one or more maturities of futures contracts on the VIX, which reflects implied volatility of the S&P 500 Index at various points along the volatility forward curve."

-- Courtesy of Yahoo! Finance