Google is going to change its financial product policy in June this year. They have mentioned in the recent blog post that cryptocurrency ads, Initial Coin offering and related content like related content cryptocurrency exchanges, cryptocurrency wallets, and cryptocurrency trading advice will be removed from June 2018. This will affect all of Google's ad products, meaning companies will not be able to serve crypto-related ads on the search engine giant’s own sites, as well as third-party sites in its network.
Just after a month of Facebook announcing that it would enforce a similar policy that bans advertisements involving bitcoin and initial coin offerings to prevent cryptocurrency related promotions that might deliberately misguide investors, google has decided to update its financial product policy.
Google's official blog : https://support.google.com/adwordspolicy/answer/7648803?hl=en&ref_topic=29265