How can I use Forex Trading (UK) returns as a source of funds for my EB-5 petition?

Sounds like it can be used if legal money. We will still need to submit five years of tax returns.

Forex can be used. You will, however, need to carefully document where you earned the money to invest and then carefully show each transaction. So it is really just a careful accounting exercise.

First of all, congrats on your trading success! Many people dabble but successful traders are rare. Good news for you: your forex gains can absolutely be used as your SOF. Our analysis here would be similar to our clients who have made massive gains in crypto, stocks, or a number of other investments. We would need more information about your initial source of capital that was deposited, the trades you made/gains, whether you have a full-time job or not, and etc. Whether you gained $500K in one month or 10 years is irrelevant - both can be done if documented correctly.

As long as the funds you invested were lawfully obtained and the profits were not the product of fraud or breaking the UK law, there should not be an issue with using your trading profits for an EB-5 investment.