IPO day and you get 1000 RSUs unlocked/vested. Share price is $80. You made 80k gains. For simplicity let's say you owed 40K in taxes.
One of two things happens:
- Hasihcorp auto sells to cover and you get 500 less shares. - You need to pay your taxes on your own and earmark 40K.
Let's pick the easy one: If Hashicorp sold for you that day you are now sitting on 500 shares with a cost basis of $80.
Let's go to today, IBM buys and the person held. 500 shares are now were $35 so the value is $17,500.
You cash out -- getting 17,500 in your account, and a capital loss of $22,500.
Sure, 17K isn't as cool as 40K, but the person still "made money" just _less_. You make it sound like this person is now "underwater" because they had a capital loss.
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And kids at home, this is why you sell some/all of your RSUs as you get them. No one company should be more than 15% of your portfolio. Even the one you work at.