What Is a B-Book Broker? A-Book vs B-Book Explained

A B-book broker takes the other side of a client's trade on its own books instead of passing the order to an external liquidity provider. An A-book broker routes the order out and earns from a markup or commission on the flow. Both are legitimate, widely used business models, and most retail brokers operate both at once, deciding per client and per instrument which flow goes where.

How it works

When your order reaches the broker, it is handled one of two ways.

A-book. The broker opens a matching position with a liquidity provider. Your profit is paid by that provider; the broker's revenue is the spread markup plus commission, and it is the same whether you win or lose.

B-book. The broker becomes your counterparty and holds the position internally. No external order is created. Your loss is its revenue and your profit is its cost.

Hybrid routing is the normal case rather than the exception. Brokers classify flow — by client, size, instrument, historical profitability — internalise part of it and hedge the rest. Internalised flow also nets: one client long a lot and another short a lot cancel out, and the broker carries no market exposure while collecting both spreads.

A-book revenue = markup + commission
B-book revenue = markup + commission + net client losses - net client profits

This is a description of order routing. It is not a description of conduct, and the two should not be collapsed into each other.

Why it matters

The B-book model contains a structural conflict of interest: the firm's revenue improves when the client's account does not. That is a fact about the incentive, and it is worth understanding before choosing where to keep money. It is not, on its own, evidence about any particular broker's behaviour. Regulated firms operate under best-execution obligations, client-money segregation and reporting requirements that exist precisely because the incentive exists — which is why the regulator matters more than the routing model.

The trade-off also runs the other way. Internalisation is what makes micro lot sizes possible and what removes rejections for size. A pure A-book routes you to real liquidity, which means real requotes at thin moments, real partial fills and real minimum order sizes. Neither model is a ranking.

The practical problem is that routing is not observable from outside. Brokers are not required to publish per-order routing decisions, and no third party can reconstruct them from trade records. So the useful question is not which book you are on. It is what your own execution actually looks like.

What the data shows

Across the public accounts on ShowMyTrades with trading history (August 2026), accounts connect through 703 distinct broker servers, and their owners have paid $4,782,670 in commissions on 1,724,575 lots. Cost of that kind is measurable because it is billed as its own line. Routing is not billed at all, which is why no figure on this page — or on any page assembled from broker records — discloses where an order went. Commission-based pricing is in use by firms on both sides of the distinction.

What can be compared is one environment against another. 429 users here hold accounts at more than one broker, and running the same rules on both over the same period separates cost and fill quality from the strategy itself. That comparison answers the question the routing label was standing in for, and it does so with numbers rather than inference.

Where you see it on ShowMyTrades

We do not label brokers A-book or B-book, and we will not: the information required to do it honestly is not available to us or to anyone outside the firm. What the account page gives you is the measurable surface.

• The Info row in the account header carries the broker badge with the trade server name in its tooltip. The server, not the brand, identifies the environment — a broker running several server groups often prices and executes differently across them.
• The Terminal panel (Terminal & Open Charts on MT5) reports Ping and Retransmission, the connection quality behind every fill.
• Advanced Statistics shows Total Commissions, Total Lots, Total Pips and Total Swap Paid. Commissions divided by lots is the account's real cost per lot; pips positive while money is flat is execution cost eating the edge.
• The Closed Trades table under Trade History & Balance Progression shows Open Price and Close Price against S/L and T/P, ticket by ticket.

Common misunderstandings

1. "B-book means the broker is trading against me personally." Internalised flow is largely netted between clients. The firm's position is the residual, not a mirror of yours.
2. "A-book means no conflict of interest." An A-book broker earns from turnover, so its incentive is volume — which is not automatically aligned with your survival either.
3. "ECN, STP or NDD in the name guarantees A-book." Those terms are unregulated marketing labels and are not audited.
4. "A bad losing streak proves manipulation." It usually proves variance. The way to test it is a second account elsewhere running the same rules, not a forum thread.

For a structured way to run that comparison, read running the same strategy at different brokers.

Related terms