Copy trading is the mechanism by which a retail client allocates a portion of their portfolio to automatically replicate the trades of a chosen leader — usually another retail trader, sometimes a vetted "Popular Investor" with verified track record, occasionally a professional fund-style manager operating under retail-friendly disclosure rules. The mechanic itself is regulatory clarity in EU/UK/AU under MiFID II, where copy trading on forex and CFDs is treated as portfolio management with explicit consent. In the US it is more constrained — registered investment advisor rules apply to anyone selling copy-eligible signals to multiple clients — which is why the meaningful copy-trading product set is European-flavoured.
The temptation with copy trading is to treat it as a way to outsource expertise. The data does not support that view. Most copy traders still underperform a passive index, and a meaningful subset lose money outright. The failure modes are documented: copying high-volatility leaders in stable market regimes (the leader's positive expected value depended on a regime that has now changed), copying leaders with insufficient track record (six months of profitable trading is not statistically significant), and copying multiple leaders without checking correlation (three 'different' forex leaders all running EUR/USD trend-follow strategies are a single bet, not three).
What copy trading does well is portfolio diversification and education. Allocating 20% of a portfolio across five vetted leaders with documented twelve-plus-month track records and uncorrelated strategies gives exposure to setups the copying trader could not run themselves, plus visibility into the rationale. The five brokers below are the five we judged most likely to give you the operational reliability, leader transparency and regulatory protection to participate constructively. None of them will guarantee returns. All of them will at least let you participate without surprise fees or insolvency risk.