Why it matters
Without negative balance protection, a flash crash can cause losses exceeding the entire account balance. The January 2015 CHF removal of the SNB floor caused some retail accounts to go negative by tens of thousands of dollars.
Regulatory requirements
ESMA (EU/EEA) and FCA (UK) regulations require negative balance protection for retail clients. Offshore brokers operating outside these jurisdictions may not provide it.
Not a substitute for proper sizing
Negative balance protection is a last-resort backstop, not a trading plan. It kicks in during gap events that bypass stop-losses entirely. Size positions so the EA stop-loss logic limits drawdown to your maximum tolerable loss before relying on this protection.