ProShares VIX Short-Term Futures ETF seeks investment results, before fees and expenses, that track the performance of the S&P 500 VIX Short-Term Futures Index. ProShares VIX Short-Term Futures ETF provides long exposure to the S&P 500 VIX Short-Term Futures Index, which measures the returns of a portfolio of monthly VIX futures contracts with a weighted average of one month to expiration.