I recently left a private company where I have some stock options which I have to decide to realise or not. If I realise them I have a hefty tax bill and because it is a private company I dont know how to sell them. So my questions are, where does a person sell shares in a private company and is there any obligation on the private company to create a market for the shares granted?
There is no obligation on the company to create a market. Some schemes will have provisions whereby the company will buyback the shares itself directly however if that is the case there are complex rules to pass to ensure that you pay CGT on the sale of shares rather than income tax on a deemed dividend.
Your options may have little or no value if there is no way you can sell the shares.