The AMZN:QQQ ratio chart crossed up on 3/17/20. It would make sense with AMZN outperforming the QQQ, that you should buy Amazon but the leverage in TQQQ outperforms almost 3: 1 better than picking a good stock.

For the period ending 8/7/20, AMZN was up 87% while QQQ was up only 61%. Picking AMZN over QQQ was 26% better.

But TQQQ was up 240% over the same time frame. It just goes to show that leverage beats superior stock picking.