Hive account@stephenrowlison actually has a pretty good post outlining some points about the SEC rulings here. https://steemit.com/blockchain/@stephenrowlison/ico-design-and-sec-rulings He briefly explains the Howey test as well. It's based on an American court case from the 40s. A Floridian farm wanted to sell tracts of land to non-farmer investors and the SEC got involved and (eventually) the Supreme Court ruled that the parcels of land are securities.