What are A-book and B-book in prop trading?

How it applies to prop firms:

• Simulated (B-book style): funded accounts are simulated; payouts come from fee revenue. Most challenge-based firms work this way.
• Mirrored (A-book style): some or all funded traders' positions are copied into a real brokerage account, so their profits are partly offset by real gains.
• Hybrid: only consistent, larger traders are mirrored.

Mirroring needs a broker or liquidity provider, capital and a way to copy trades. It changes the firm's risk from payout risk to market risk.

PropExecutor is simulation-only and never routes orders. Firms that mirror traders do it with separate brokerage tools, using PropExecutor's account data to choose whom to copy.

Disclosure

If you mirror some traders into real markets, your terms should not imply that every account is real. Describe it as a risk management activity of the firm.

Most new firms start fully simulated and consider mirroring only once they have a consistent group of profitable funded traders.