It is so extremely common that we were educated about it repeatedly in Engineering school.
Entire divisions get shut down over night when stock values go down. This is reality in the largest corporations (P&G, GE, GM, etc). Often the managers don't even know they are on the block.
Maybe Silicon Valley has been shielded from this reality of corporate culture in established industry by stocks that have tended to go up.
But also I suspect there are probably compliance issues related to insider trading about giving employees with stock or stock options a heads up.
