Who Regulates What: SEC, CFTC, FCA, ESMA
Different regulators have jurisdiction over different products and different geographies — a US equity option, a US futures contract and a UK-listed stock can each answer to a different regulator, and knowing which one matters the moment something goes wrong.
A trader working a US book routinely crosses several regulators' jurisdiction without leaving their desk. Trade a stock, and it's the SEC's territory. Trade the futures on that stock's index, and it's the CFTC's. Trade the same underlying company's shares listed in London, and the FCA is watching instead. Understanding which regulator applies is not trivia — it determines the rules a trade has to follow and who to call when something breaks.
The main split: securities vs derivatives, US vs UK/EU
| Regulator | Jurisdiction | Core mandate |
|---|---|---|
| SEC (Securities and Exchange Commission) | US securities: stocks, bonds, equity options, mutual funds, most ETFs | Investor protection, fair and orderly securities markets, disclosure |
| CFTC (Commodity Futures Trading Commission) | US derivatives: futures, most swaps, commodity markets | Market integrity and stability in derivatives markets |
| FCA (Financial Conduct Authority) | UK financial services broadly: banks, brokers, exchanges, listed companies | Consumer protection, market integrity, competition |
| ESMA (European Securities and Markets Authority) | EU-wide securities markets, coordinating national regulators | Harmonised rules and supervisory convergence across EU member states |
The SEC/CFTC split inside the US is the one that trips people up most, because it is a product-type split rather than a company or exchange split: the SEC oversees the stock, the CFTC oversees the futures and most swaps on that same stock, and a security that is both — like a single-stock future — can require both regulators to coordinate.
Jurisdiction usually follows the instrument, not the venue or the trader. The same desk trading the same underlying company can be subject to different regulators depending on whether the instrument is a security, a future, or a swap.
Why the UK and EU look similar but aren't the same
Before Brexit, the FCA operated inside the same EU regulatory framework that ESMA coordinates. Since the UK's departure, the FCA sets UK rules independently, while ESMA continues to harmonise rules across the remaining EU member states and their national regulators (Germany's BaFin, France's AMF, and so on). A firm operating across both London and continental Europe today has to satisfy two separate, no-longer-identical rulebooks — a real operational cost that didn't exist before 2020, and one still being worked through as UK and EU rules gradually diverge.
What this means for a working quant
Regulatory jurisdiction determines concrete, practical things: which reporting regime a trade falls under, which position limits apply, what counts as market abuse in that jurisdiction (see What Counts as Market Abuse), and which disclosure rules govern a public company's material information (see Regulation FD and Selective Disclosure, a US-specific rule with no exact EU equivalent). A strategy that is entirely legal under CFTC rules for a futures contract may need a different compliance review if the same economic exposure is expressed through an SEC-regulated security instead.
"Regulated by the SEC" and "regulated" are not synonyms. A great deal of derivatives activity — most swaps, all futures — sits with the CFTC instead, and some products and venues (certain crypto markets, for instance) have spent years in genuine jurisdictional ambiguity between the two. Don't assume a US regulator is watching just because a US regulator exists.
Further reading
- SEC, About the SEC
- FCA, Our Approach to Supervision