Yes, U.S. citizens can invest in startups outside of the U.S., but there are a few things to keep in mind.
First, you'll need to make sure the startup is registered with the Securities and Exchange Commission (SEC) in order to comply with U.S. securities laws. You can check the SEC's website to see if the company is registered.
Second, you'll need to make sure the company is reputable and has a good track record. You can research the company online, or you can speak to someone who is familiar with the company and the startup industry.
Third, you'll need to make sure you understand the risks involved in investing in a startup. Startups are often high-risk investments, and there is a chance you could lose all of your investment. You should only invest what you can afford to lose.
Fourth, you'll need to diversify your investment portfolio. Don't put all of your eggs in one basket, so to speak. Invest in a variety of companies and industries to minimize your risk.
Finally, you'll need to consult with a financial advisor to see if investing in a startup is right for you. A financial advisor can help you understand the risks and potential rewards of investing in a startup.