Every retail broker says they are A-book. Most are hybrid. Here is what the routing models actually look like, and the execution signals in your own trade history that reveal which one you are getting.
The routing model your broker uses creates fundamentally different incentives:
Understanding which model you are trading against affects how you interpret slippage, spreads, requotes, and even withdrawal experiences.
"A-book" originated in dealing-room jargon, where order tickets were sorted into two physical books. Book A was customer orders to be hedged externally. Book B was orders the dealer kept internally.
On a modern MT5 A-book broker, your order flow is:
Two revenue models, often combined:
"Raw spread" or "ECN" accounts typically use the commission model. "Standard" accounts typically use the spread-markup model. Both can be A-book or B-book - the account-type name does not tell you which.
On a B-book broker, your order never leaves the broker's server. The broker takes the other side internally.
Your order flow:
They profit when you lose. If you go long EURUSD at 1.0800 and close at 1.0750, you lose 50 pips. The broker just made 50 pips on the opposite trade they took.
The strong version of this picture: a B-book broker has a strong economic incentive for you to lose. The honest version: most B-book brokers risk-manage their book aggressively. They do not "rig" trades - they would face regulatory action if they did. But they do net out positions and hedge their net exposure externally only when it becomes uncomfortable.
B-book is a perfectly legal market-making model. CME-listed futures markets have official market makers who B-book virtually all order flow. The model is fine. The risk is in the broker's discipline and incentive alignment.
In practice, almost every retail forex broker is hybrid. The broker classifies accounts into tiers based on:
Then they route based on the classification. Common hybrid logic:
| Account profile | Typical routing |
|---|---|
| Small account, high frequency, mostly losing | B-book (broker profits) |
| Small account, infrequent trades | B-book (low risk) |
| Large account, profitable | A-book (broker hedges - too risky to internalise) |
| News scalper | A-book (broker does not want news exposure) |
| Algo with positive expectancy | A-book |
The classification can change. A trader who was B-booked while losing can be moved to A-book once they become consistently profitable. The broker is essentially saying "you are too dangerous to hold internally".
You can never know for certain. But you can infer from your own MT5 trade history.
Right-click any closed trade in the History tab, choose Properties. Look at the Comment field. On many A-book brokers, the LP venue or LP code appears:
LMAXCITIFXUBS_EXJPM_FXIf you see these consistently, the trade was A-booked. If comments are empty, generic ("market" or "order #12345"), inconclusive.
Track 100+ market orders. Calculate the slippage on each (fill price minus requested price). On an A-book broker, the distribution should be roughly symmetric: sometimes you get positive slippage, sometimes negative.
On a B-book broker, slippage often skews negative: you rarely get a better price than requested, you frequently get worse. This is because the broker has discretion over fills and uses it.
During major news (NFP, FOMC, CPI), watch the spread on the same symbol:
Between 22:00 UTC and 00:00 UTC, liquidity is genuinely thinner globally. A-book brokers show wider spreads during this window because the LPs do. B-book brokers can keep spreads tight because they are setting the prices themselves.
If your broker's spreads are identical at 14:00 UTC and 23:00 UTC, that is a strong B-book indicator.
Requotes (the dialog saying "price changed - accept new price?") happen on Instant Execution accounts. Most A-book brokers use Market Execution now, so requotes are essentially extinct on A-book. If you get frequent requotes, you are on Instant Execution, which is much more common on B-book setups.
Tier-1 regulated brokers (FCA, ASIC, BaFin, CySEC) publish Order Execution Policies and Best Execution Disclosures. Read them. They typically describe routing in general terms:
Offshore brokers in jurisdictions like Saint Vincent or Vanuatu generally do not publish these documents. The absence of disclosure is itself a signal: those brokers can do whatever they want.
Pure A-book sounds great for the trader and several brokers advertise it. The reality is that running pure A-book is hard:
So even brokers who genuinely aim for A-book end up B-booking small-lot retail flow out of necessity. This is honest and standard.
You almost never know for certain. The signals in section 5 give you a probability estimate. If your broker is regulated and has a published execution policy, read it.
Yes. Routing decisions are made server-side and can change daily, hourly, or per-trade. The broker does not need to notify you. This is legal and standard.
Electronic Communication Network. A direct-market-access routing model where orders go to an actual matching venue (not just an LP). True ECN brokers are rare in MT5. Most "ECN" branded accounts are actually STP (Straight Through Processing) which is the same as A-book.
Essentially yes. STP is "Straight Through Processing" - your order passes straight through to LPs. A-book is the same concept from a different angle. Both terms refer to routing externally rather than internalising.
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