I lived in US for more than 9 yrs on H1B visa and was maintaining US stock portfolio and was filing taxes in US as 1099 for stocks plus my salary as 1040. Now I am planning to return to India but wish to continue my US trading with stocktrade. I will be trading in US as non resident US which means W8-Ben will deduct 30% on my profit on the stocks. My question what would be my tax liabilities in India on my stock profit in US which is already taxed once and what if in future I transfer all my US money to India? All US money has already taxed in US thru 1040/1099.
my tax liabilities in India on my stock profit in US
You would need to pay tax on the profit in India as well after you have become resident Indian. India and US have a double tax avoidance treaty. Hence if you have already paid tax in US, you can claim benefit and pay balance if any. For example if you US tax liability is 20 USD and Indian liability is USD 30, you just need to pay 10 USD. If the Indian tax liability is USD 20 or less you don't need to pay anything.
what if in future I transfer all my US money to India?
The funds you have earned in US while you were Non-Resident is tax free in India. You can bring it back any-time within a period of 7 years.