Hi cs-szazz. I remember being in your situation; it's frustrating because you can't Google for answers. Here is advice I was given when in a similar situation.

- Find the other people at the company in your situation (size of grant, type of options). Share your learnings with each other. Consider getting professional advice, the Bay is full of attorneys and CPAs for whom this is a familiar situation.

- If you're at a unicorn, you probably have co-workers who are veterans of other unicorns and have been through this before. Ask them for advice (or an introduction to their source of professional advice)

- As a group, consider asking your board to arrange a limited second market sale to cover exercise costs and taxes. Many institutional investors are happy to buy a little extra stock, especially if it helps with keeping senior staff happy and focused on the right things.

- If you're going to be doing anything involving stock without board approval (like trying to build some kind off house-of-cards, pseudo-legal collateral package for a loan shark) you really need to hire an attorney.

- if you only have options, you might not be a shareholder. Your rights and access to information might be different once you've exercised a share.

- You can't extend the 90 day exercise window on ISOs, that's a federal law thing. The company can convert to NSOs to extend the window, but the setup for that conversion is complicated and expensive.