Among the best performing non-leveraged ETFs of Friday, the iPath Series B S&P 500 VIX Short Term Futures ETN (VXX) increased 4.5% and the ProShares VIX Short-Term Futures ETF (VIXY) gained 9.4%. The CBOE Volatility Index and volatility-related exchange traded funds jumped Friday on growing anxiety over the pace of the Federal Reserve's future interest rate hikes. But a failure to restore price stability would mean far greater pain.” “Reducing inflation is likely to require a sustained period of below-trend growth,” Powell said in his speech.