Start-ups have begun issuing new digital currencies via ICOs, also known as token or coin sales, that are sold to investors in return for a crypto-currency like bitcoin or ether.
"There are clear risks associated with these offerings," the International Organization of Securities Commissions said in a statement.
"ICOs are highly speculative investments in which investors are putting their entire invested capital at risk."
IOSCO groups regulators like the U.S. Securities and Exchange Commission, and Britain's Financial Conduct Authority, which said in December it would step up scrutiny of ICOs.
(Reporting by Huw Jones, editing by Carolyn Cohn)
