How does the insider policy works if someone wants to buy stock or trade in future options before joining a company (after offer accept). Planning to buy some stock before i move to new employer as market is crashed a bit in last few days. How does the selling rule apply? I think for stock we can sell in trading window but how does options works as they have their own expiry date. Do we need to check with company or broker who manages RSU's or draft 10b5-1 trading plan?
^ true except once you've joined, you may have insider info, and any sale outside of open period can become suspect.
Right, but I think OP's question was specifically about before joining.
It applies to selling your options, even if you bought them before you joined. You don't want to buy and not be able to sell right?
As long as you haven't gotten any material insider info yet (unlikely), go for it. You're not on their payroll yet, so you're not subject to any of their restrictions.
how about options? because they have their expiry and will probably expire/exercise based on that date rather than trading window.
As long as the end transaction happens automatically, you SHOULD be fine. If you have to initiate something, even if it's just an explicit "exercise the option that I bought a month ago", that's when you'll run into problems.