If it's anything like Apigee IPO it would be a huge disappointment for their employees
Summer 2014 Apigee raises last private funding at a $600M valuation
April 2015 Apigee IPOs at a valuation of $500M
By end of 2015 Apigee closes at a valuation of ~$250M.
So the company lost almost 2/3rds of its value probably right as the lockup period was expiring for employees to sell shares.
Facebook had a similar valuation decline, then a bounce back.
So those who had faith in the company for another year saw modest gains compared to 1.5 yrs ago at IPO.
Maybe a good rule of thumb is 10-20% of the company could be owned by employees at the time of IPO which could materially change the share price.
But before that the stock traded as low as $6. So during this time the employees' stock was underwater, whereas C level will have been able to sell a portion of their shares at IPO (vs employees waiting for their 6 month lockup to expire).
But the stock had recovered to $16+ before the acquisition so... I mean it's a public company. "Up and to the right" isn't always the case