"Central to determining whether a security is being sold is how it is being sold and the reasonable expectations of purchasers," William Hinman, head of the Division of Corporation Finance at the SEC, said in a speech at the Yahoo All Markets Summit: Crypto conference in San Francisco.

https://www.cnbc.com/video/2018/06/14/bitcoin-and-ether-cryptocurrency-surge-on-new-sec-ruling-securities.html

https://www.sec.gov/news/speech/speech-hinman-061418

https://www.wired.com/story/sec-ether-bitcoin-not-securities/