3x leveraged ETFs like the ProShares UltraPro QQQ and Direxion Semiconductor Bull 3x are not foolproof long-term holdings and would suffer badly in a dot-com or GFC-style decline. They target 3x daily returns, and the daily leverage reset compounds losses in volatile periods. The Nasdaq one launched in 2010 at the start of a ZIRP bull market; backtested to the late 1990s it would still be underwater. A 2x software ETF holding Adobe, Microsoft and Salesforce was discontinued this April. x.comÂ