以QQQ為例，要保護的是下跌的部分， QQQ不會跌到0. 所以如果用這個例子中

來源: 於 2025-05-29 14:47:17 [博客] [舊帖] [給我悄悄話] 本文已被閱讀：次
  • Put spread premium is $7, if QQQ drops to 490, you will only incur 75% of the actual loss.
  • If QQQ continue to drop, you can roll this down to next level, something like 495-465, and again, you will incur maybe 50-70% of the loss from 495 to 465.

All in all, when direction is right, you can protect your porfolio such that 50-70% of the drawdown is avoided. 

In real life, stock hardly drop from 520 to 465 without any bounce, so there are other ways to gain more protection.