DCMs are a creature of rule, not statute [1]. The statutes that animate it are the CFMA of 2000, Dodd-Frank "special rule" for event contracts and CEA § 5. The core question, whether the CFTC has the authority to regulate this kind of DCM, is still open.
> There is already a split decision on this between the 3rd and 9th circuits so it seems likely SCOTUS is going to take this up
Links to the split opinions?
[1] To be clear, DCMs are undefined in statute. DCMs are just referenced in other statute. Part 38 is an implementing regulation.