A bitcoin sign is seen during Riga Comm 2017, a business technology and innovation fair in Riga, Latvia November 9, 2017. REUTERS/Ints Kalnins

FRANKFURT (Reuters) - Europe’s top markets regulator has warned investors about the pitfalls of buying newly issued crypto coins, an experimental and unregulated form of online crowd funding particularly used by start-up businesses.

The European Securities and Markets Watchdog (ESMA) said on Monday such Initial Coin Offerings (ICOs) were unregulated, volatile, not transparent and technologically untested.

“ICOs are extremely risky and highly speculative investments,” the agency said, adding there was a risk of “the total loss of your investment”.

“Many of the coins or tokens ... have no intrinsic value other than ... to use them to access or use a service/product,” said the agency, warning coin issuers they may be subject to existing regulations.

After Swiss and Wall Street regulators, ESMA is the latest to demand tighter scrutiny of cryptocurrencies. China has banned ICOs.

By creating and issuing digital tokens, entrepreneurs can sometimes raise tens of millions of dollars within hours - with little regulatory oversight. Token holders are generally not given a share in a project or security.

ICOs have fueled a rapid rise in the value of all cryptocurrencies, from about $17 billion at the start of the year to a record high of close to $180 billion in early September.