Lock-up agreements

[Gene]

I own stock options in a company that is getting ready for an IPO. They want me to sign a "lock-up" agreement which would prevent me from trading the stocks for 180 days after the stock goes public. Can they hold me to the 180 days if I don't sign the lock-up agreement?

Thanks.

 

[lg2]

it may depend on the relevant SEC laws concerning ownership and sale before and after an IPO
A possible information site might be www.IPOlockup.com