I've seen a number of news outlets reporting on this as an 'insider trading' case. I don't think that's necessarily the best way to look at the set of facts at issue.
There is no specific, brightline section of the U.S. Code that criminalizes 'insider trading' per se; rather, the term has typically been associated with a set of activities that can rise to the level of Securities Fraud, which most definitely is a statutory concept. The securities fraud concept clearly does not apply here, at least not to the first level conspirators.
It would seem to me that Rozier, Billups, et. al could most effectively be prosecuted (at the Federal level) pursuant to the Wire Fraud and RICO statutes. But suffice to say these clowns are looking at some serious Fed time.
Where the concept of Securities Fraud COULD come into play is with shareholders in the betting platforms that took the wagers.
Those shareholders could point to the betting platform's 'terms and conditions', which typically (at least DK and FD that I know of) state that participants are not allowed to place wagers based on information that is not publicly/broadly available. Therefore, a shareholder could claim injuries under the Securities Fraud statute to the degree they could prove financial harm due to the platform's failure to enforce said policies.
Fascinating stuff. Can't wait to see where this goes.