Google has moved to ban crypto-currency advertising from its platforms.
The move will affect promotional campaigns for initial coin offerings, Bitcoin exchanges, digital wallets to store the assets and trading advice.
A notice said the policy would be introduced in June but did not give an explanation why.
It follows a similar move by Facebook in January, which said many firms in the sector were acting in bad faith.
Google’s decision will affect ads displayed both in its search results and YouTube, as well as those placed on third-party sites via its ad platforms.
The value of Bitcoin, Ethereum and Ripple all dipped after the news emerged at about 04:00 GMT.