Further breaking down inverse and leveraged ETF assets, 44% of assets are in bearish short and leveraged products and 56% is allocated to bullish double- or triple-leveraged funds, according to Boost data. Boost notes leveraged Europe ETFs have gained popularity this year. In the U.S., investors have poured $17 million into the ProShares Ultra FTSE Europe (NYSEArca: UPV) and $55.5 million into the Direxion Daily FTSE Europe 3x Bull Shares (NYSEArca: EURL). EURL, which debuted in January 2014, attempts to deliver three times the daily performance of the FTSE Developed Europe Index, the underlying benchmark for VGK. [Leveraged Europe ETF in the Spotlight]

Among U.S.-listed inverse and leveraged ETFs, the top asset gatherers at the end of the second quarter on a year-to-date basis included the Direxion Daily Gold Miners Bull 3X Shares (NYSEArca: NUGT), ProShares UltraShort S&P500 ETF (NYSEArca: SDS), Direxion Daily Energy Bull 3X Shares (NYSEArca: ERX) and the ProShares UltraPro QQQ (NasdaqGM: TQQQ), according to Boost data.

Chart Courtesy: Boost