// CHAPTER 6 · 4:06
Every Form ATS-N, read and scored, so a change in the rules surfaces when it happens.
Every ATS operates under Regulation ATS and files Form ATS-N with the SEC, describing how it matches orders, who can use it and what it charges. We track more than twelve hundred of those filings, every material amendment, update, order-flow filing and cessation.
The regulatory monitor reads each filing as it lands, summarises what changed and scores its impact, so when a venue changes its matching logic, its fees or its access rules, it surfaces here the week it happens. Exchange rule changes are tracked the same way, through more than two thousand 19b-4 filings.
And when you trade, every fill comes back with a code saying how it executed. We decode 965 of them across sixteen exchanges and three ATSs, each one sourced.
