* Latest in series of warnings from around the world
* People say they invested in U.S. stocks
* Company also says it is offering cryptocurrency (Adds background)
By Kirstin Ridley and Carolyn Cohn
LONDON, May 17 (Reuters) - Britain's financial markets watchdog said on Thursday it had put UK-registered firm Financial.org on an investor alert list, warning investors from dealings with the company.
The Financial Conduct Authority (FCA) warning is the latest from regulators around the world about the company, a sponsor of Formula One team Williams.
The FCA said in a notice posted on its website that it believed Financial.org "has been providing financial services or products in the UK without our authorisation".
Offering investment services without regulatory permission is a criminal offence in Britain.
Reuters could not reach Financial.org by telephone. A receptionist on the ground floor of the office building in London's Canary Wharf financial district where the company rents space on the 26th floor, said Financial.org had changed its name to Mythen. Her call to the office went unanswered.
Williams did not respond to a request for comment.
Reuters has reported that Financial.org, which describes itself as an educational platform, is managing hundreds of thousands of dollars for Middle Eastern and Asian investors even though it is not licensed to engage in financial transactions.
Seventeen people from China, Indonesia, Malaysia, Singapore, Thailand, Vietnam and the UAE have told Reuters they had each given between $3,000 and $400,000 to Financial.org.
Most said their money had been invested in U.S. blue-chip stocks. Recent notices on a website described as the official news site for Financial.org say that the company is also offering a cryptocurrency called FOIN.
Financial.org has told investors it will close their accounts and take 20 percent of their money if they do not raise their minimum investment to $10,000 from $3,000, according to a notice posted on its website and seven investors.
The deadline for this has been extended to the end of May, one of the investors told Reuters, providing a screenshot of the latest notice posted on a password-protected, members-only section of the firm's website.
The investor also said attempts to withdraw money had failed. The person, who declined to be named due to concern about their investments, provided screenshots of an account page showing withdrawal requests had been rejected. (Editing by Sinead Cruise/Alexandra Hudson/Alexander Smith)