I just got an offer, which requires a 3 month notice period as stated in the contract. The company is a hedge fund company.

Is this common in the industry? How big is the chance for me to amend this condition in the contract?

Thanks

Q:How big is the chance for me to amend this condition in the contract?
A:At least give a try.

3 month notice, seems you are taking some important / sensitive job.
usually it's 1 month.