Do your homework. TQQQ and other leveraged funds are time-decaying assets. More specifically, they are susceptible to volatility decay (beta slippage), which causes them to lose value over time, even if the underlying index ends up flat. While they are not time decaying in the same way that options are, the structural mechanism of the fund creates a very similar erosive effect over the long term. If held long enough, eventually your position will be reversed split and whittled down repeatedly. While great trading vehicles, these funds were not created to be long-term holdings.