That only helps you if your rebalancing period is less frequent than it should be, letting your leverage drift up on good days and down on bad days. If the mark

That only helps you if your rebalancing period is less frequent than it should be, letting your leverage drift up on good days and down on bad days. If the market goes down by 16.6%%, your levered ETF goes down by 50%, and your portfolio is now 80% treasuries and 20% 3x levered ETF. If you rebalance daily in order to maintain your desired stock exposure, you end up owning the S&P 500 as your buy and sell orders of the levered ETF counteract the ETF's buy and sell orders on the underlying index to maintain its leverage. All you're doing is paying higher fees, trading costs, the spread on T-bills vs institutional margin costs, and realizing capital gains and losses pointlessly. What you want is to buy call options on the S&P 500 index. The market is far more efficient here and way better for you.