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I am not a US resident/tax resident, neither an employee or employer of the US company. I am now get very confused in response to tax assessment for trading the US Stock options/underlying stocks. Please also advise me that the money gain subject to either "income tax" or "CGT for these scenarios in a stock / option tradings Case 1) I bought a US stock call option (say GBP10) but i didn't exercise my option right sell it on/before the end of contract, i had realized the net gain(say sold at GBP11.5) /loss(say sold at GBP 9) (i.e. selling price - buying price= GBP1.5 net gain/GBP1 net loss ) In some cases, the option will turn to ZERO value at the end date of contract. In this case, no real stock buying/selling was involved that only subject to CGT ? Case 2) Similar to Case 1, I bought a US stock put option (say GBP10) but i didn't exercise my option right sell it on/before the end of contract, i had realized the net gain(say sold at GBP11.5) /loss(say sold at GBP 9) (i.e. selling price - buying price= GBP1.5 net gain/GBP1 net loss ). In one case, the stock option for the underlying stock is now dropped to a certain level that I have to exercise the option right in hand, therefore, the stock option will turn to ZERO value( will offset the gain in CGT?), the stock I have to sell will subjuct to CGT , is that right ? Case 3) Similarly, I sold out a stock option at GBP10 and generate the money an income then waiting till the end of the contract. However, a) the option buyer exercise the option right that I have to use my own money to buy this underlying stock at GBP100 as the agreed price. Then I sold out the stock at the market and realized gain (say sold at GBP 115) or loss (say sold at GBP90). b) the option buyer exercise the option right that I have sold my stock in hand at the agreed price GBP 100. However, I realized the net gain/loss depends on the original price for the stock i bought in. So, the above realized gain or loss would subject to CGT but not income tax?? Many thanks in advance.