High-frequency trading
High-frequency trading (HFT) is algorithmic trading that submits and cancels large numbers of orders in fractions of a second, profiting from tiny, short-lived price discrepancies.
Genuine HFT is an institutional discipline of colocated servers and exchange market-making, far from retail reach. On prop-firm rule pages the term means something narrower: bots that exploit the simulation itself, most notably latency arbitrage — trading on a fast external price feed against a sim feed that lags by milliseconds — and burst strategies that fire many orders per second at prices a live market would never have filled.
Firms prohibit these because the profits are artifacts of the demo environment. A simulated fill consumes no real liquidity, so an exploit can print gains that would never replicate live — and a firm paying real splits on that edge loses money mechanically. Bans on "HFT" at most firms sit alongside bans on latency arbitrage, tick scalping, and feed manipulation.
The line to ordinary automation matters. Rule-based EAs and algorithmic entries are commonly allowed, and manual scalping is permitted at most firms, provided trades last beyond any minimum duration the firm sets; reviews commonly flag accounts whose average hold time is measured in seconds or less.
In a prop-firm challenge
Passes produced by exploit bots — some sold openly online — are commonly voided at review, with the fee kept and the trader banned: an account breach by conduct rather than by loss. The clauses doing that work are unpacked in prop firm rules explained.