[leelin]

Officially, founders typically only hold common shares (often with further restrictions). Common shareholders should get $0 when selling for less than money raised because of liquidation preferences.

However, the acquiring company usually wants to retain some of the team. The founders often receive an employment offer, and that offer can contain anything negotiated, including signing or performance bonuses.

There can be some conflict of interest and negotiation ugliness if the investors view the employment offers as too generous at the expense of shareholders. In practice, most decent investors would prefer to spend their energy on their big winners rather than optimize a small loss into break-even.

http://www.paulgraham.com/growth.html#f12n