Its a negotiation that happens with the bank that is taking the company public. They are trading off the 'optics' of a bunch of people selling their stake at the IPO vs value. The lockup period for executive (officers) and non-officers is also negotiated.
The bankers want to strike a balance between employees (especially officers) who have concerns about being whipsawed with the stock price and the perception that they feel the company will grow in value over time so holding the stock is a "good" investment.
The bankers want to strike a balance between employees (especially officers) who have concerns about being whipsawed with the stock price and the perception that they feel the company will grow in value over time so holding the stock is a "good" investment.