By "zero out," do you mean they were previously valuable and then dropped below their strike price after accounting for the > 1x preference? That sucks and I'm sorry it happened to you. It's still pretty unusual though.

Curious to hear - were any of the following factors in play: (i) the company was struggling to stay afloat, (ii) the company was located outside SF/NYC, (iii) the company had less-experienced founders?