Brokers describe themselves as regulated. The question is by whom, and under which of the broker's entities your account sits, because the protections differ and the same brand can offer several.
The main regulators
The FCA in the UK: segregated client money, FSCS cover up to £85,000 if the firm fails, negative balance protection, leverage capped at 1:30 on majors, and the Financial Ombudsman for disputes. ASIC in Australia: segregation, negative balance protection and the same leverage caps since 2021, with a strong enforcement record but no compensation scheme equivalent to the FSCS. CySEC in Cyprus, which is the most common EU regulator for retail brokers: EU rules under MiFID II, an investor compensation fund of up to €20,000, and the ESMA leverage caps. ESMA itself does not regulate brokers directly; it sets the product rules that EU regulators apply, and the UK kept them after leaving.
Offshore
Brokers licensed in St Vincent, the Seychelles, Vanuatu, Belize, Mauritius and similar jurisdictions can offer leverage of 1:500 or more, bonuses, and fewer questions at sign-up. They can do so because the regulator requires little. There is usually no compensation scheme, no ombudsman, no enforced segregation, and no practical route to recovering money from a firm that fails or refuses a withdrawal.
The multi-entity trick
Large brokers operate several entities, one under the FCA, one under CySEC, one offshore, under one brand. Which entity holds your account is decided at sign-up, often by your country and sometimes by a question about wanting higher leverage. The protections belong to the entity, not the brand. A UK resident who accepts an offer of 1:500 leverage from a well-known brand has been moved to its offshore entity and has left the FCA's protection behind, whatever the logo says.
Two traders open accounts with the same brand. The first signs the FCA entity's agreement: 1:30 leverage, FSCS cover, ombudsman. The second, wanting more leverage, is routed to the Seychelles entity: 1:500, no compensation scheme, disputes under Seychelles law. The brand, the platform and the spreads are identical. If the firm fails, one of them is covered up to £85,000 and the other is an unsecured creditor.
An EA that sizes by risk gains nothing from 1:500 leverage, so the only thing an offshore entity offers is the removal of protection. Check the regulator's register for the exact entity named in your account agreement, not the brand. For a UK resident, the FCA entity is the sensible home for any account an EA will run on, and the leverage cap is not a constraint on any strategy worth running.