Why one word, 'security,' changes everything
In the US, whether a digital asset is legally a 'security' or a 'commodity' determines which regulator has jurisdiction, and the practical consequences are enormous. If a token is a security, offering or trading it generally requires registration and disclosure obligations under securities law, exchanges that list it face a much heavier compliance burden, and issuers face restrictions on how they can sell it to the public. If a token is a commodity, oversight generally falls to the CFTC (Commodity Futures Trading Commission), which has historically had a lighter, more derivatives-focused regulatory touch on spot markets. The SEC and CFTC have overlapping but not identical claims to authority here, and for years neither agency, nor Congress, had definitively settled which digital assets fall into which bucket.
This ambiguity is not academic. It has driven real enforcement actions against major exchanges over which listed tokens were allegedly unregistered securities, has made it genuinely hard for a new project to know in advance which rulebook applies to its token, and has pushed some crypto activity offshore to jurisdictions with clearer rules. 'Market structure' legislation, in this context, means bills aimed at drawing a clear line: creating defined criteria for when a token is a commodity versus a security, and assigning clear regulatory jurisdiction over crypto spot markets, something that, unlike securities and commodities markets generally, has lacked a single clear federal regulator for spot trading.