What’s the best way to negotiate the sale of your company?

Justin Kan (Partner at Y Combinator)
The Founder’s Guide To Selling Your Company

You can tell if an offer is bullshit because it will not be accompanied by an expiration date and/or a promise of a term sheet delivery within a very short period of time (24-48 hours). When a sufficiently high-up decision maker decides he/she wants to buy your startup, he/she will attempt to meet with you constantly and put time pressure on you, so as to prevent you from shopping the deal and getting a better offer.