you are issued equity in the form of stock options. Stock options give you the opportunity to buy stock in the company at a specific "strike price" enshrined as the fair market value of the company when you sign your offer letter.
you aren't actually vesting stock month to month you are vesting your stock options. when you "exercise" your stock options you pay the company the strike price * number of options you want to exercise in order to purchase the actual stock in the company.
If the company has grown in value since you joined then you would have a taxable event upon exercising your stock options because you are buying the stock at the strike price, but the fair market value of the stock is significantly higher, so that is a taxable capital gain that you have to deal with.
Any sane company will give you a 10-year exercise window after leaving the company to actually pull the trigger and "exercise" your stock options so that you don't incur a tax liability but some companies only give you three months. Which means not only do you have to front the cash to "exercise" the options, but you also have to pay the tax liability on the capital gain of stock for that year.
If you're asking how you can possibly be expected to pay the tax on a million dollar+ capital gain, without ever even having access to cash or a guarantee you even will have access to cash in the future, then welcome to the scam that is being an employee at a Silicon Valley startup and the fucked up logic of the US tax code.
you aren't actually vesting stock month to month you are vesting your stock options. when you "exercise" your stock options you pay the company the strike price * number of options you want to exercise in order to purchase the actual stock in the company.
If the company has grown in value since you joined then you would have a taxable event upon exercising your stock options because you are buying the stock at the strike price, but the fair market value of the stock is significantly higher, so that is a taxable capital gain that you have to deal with.
Any sane company will give you a 10-year exercise window after leaving the company to actually pull the trigger and "exercise" your stock options so that you don't incur a tax liability but some companies only give you three months. Which means not only do you have to front the cash to "exercise" the options, but you also have to pay the tax liability on the capital gain of stock for that year.
If you're asking how you can possibly be expected to pay the tax on a million dollar+ capital gain, without ever even having access to cash or a guarantee you even will have access to cash in the future, then welcome to the scam that is being an employee at a Silicon Valley startup and the fucked up logic of the US tax code.