PS: https://www.irs.gov/taxtopics/tc427.html
Statutory Stock Options If your employer grants you a statutory stock option, you generally do not include any amount in your gross income when you receive or exercise the option. However, you may be subject to alternative minimum tax in the year you exercise an ISO. For more information, refer to the Form 6251 Instructions (PDF). You have taxable income or deductible loss when you sell the stock you bought by exercising the option. You generally treat this amount as a capital gain or loss. However, if you do not meet special holding period requirements, you will have to treat income from the sale as ordinary income. Add these amounts, which are treated as wages, to the basis of the stock in determining the gain or loss on the stock's disposition. Refer to Publication 525 for specific details on the type of stock option, as well as rules for when income is reported and how income is reported for income tax purposes.
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Not Readily Determined Fair Market Value - Most nonstatutory options do not have a readily determinable fair market value. For nonstatutory options without a readily determinable fair market value, there is no taxable event when the option is granted but you must include in income the fair market value of the stock received on exercise, less the amount paid, when you exercise the option. You have taxable income or deductible loss when you sell the stock you received by exercising the option. You generally treat this amount as a capital gain or loss. For specific information and reporting requirements, refer to Publication 525.
As to stock options they are best treated as lotto tickets. Unless you think the company is very likely to get sold or go public at a high valuation you’re generally better off ignoring them.