You don't pay tax on capital, only on capital gains, that is increase in asset value when you sold and didn't buy back within like 28days? Varies with every country.
You get tax on income, you don't get tax relief from gambling losses unless you can prove that the lost occurred due to operating a gambling business which is possibly illegal in your place without a licence.
So you need to pay tax on your winnings if you declare them. They don't care if you lost it or not.
Unless you are non-US citizen and non-resident, I think US- guys are taxable worldwide I am not sure since I am not US guy but I have US companies.
It is easy not to pay any tax legally in your situation but quite complicated to implement the scheme so I'll leave it out.
I only typed this out cause not much to do while waiting for friend to transfer me $200 to
HUGEFISH2888@epassporte.com for hookers in Thailand. Only got Epassporte visa with me which is running out of hooker cash and Partypoker barred cashier access from Thailand!!!