There’s a particular kind of frustration for traders who have backtested a strategy and let it print money on a new account, only to see it suddenly fail after a few weeks. If this sounds familiar, your broker’s order-routing practices might deserve more scrutiny than your system.
Between 74% and 89% of retail forex accounts lose money, and this is a statistic brokers know very well, one that shapes how they handle clients’ trades. Understanding how orders are handled is a key knowledge for anyone serious about trading profitably.
In this article, we’ll cover:
- How brokers handle client orders
- Why new accounts enjoy good conditions
- Which strategies are vulnerable to changes in execution settings
- How traders can protect themselves
What are A and B-books
When a broker A-books your trades, they pass them straight through to a liquidity provider (LP). They make money on the spread and commission, and don’t care whether you win or lose. In contrast, when they B-book your trades, they take the other side, and your gains become their losses.
Most retail brokers run a hybrid form. Profitable traders, large positions or strategies considered risky are routed to A. Everyone else stays on B where the broker has a direct financial interest in their failure. This isn’t something your broker will mention openly when you sign up.
Why new accounts often win
Here’s where it gets interesting. When you open a fresh account, the broker doesn’t know you yet. New accounts are usually B-booked by default, which often means better trading conditions. There’s no execution delay as the broker isn’t hedging your trades externally. As a result, fills feel cleaner and your strategy works perfectly.
Some traders report that this honeymoon period coincides with their best results. That’s because it aligns with the company’s profile-building window. They’re watching your win rate and your strategy’s performance. The moment you start looking like a consistent winner, especially if you’re scalping or trading news, you become a liability on their book.
How the switch kills your edge
You won’t get a notification when they put you on the A-book, but you will notice that things start to feel a bit off.
Execution quality is where the damage shows first. Here are the common symptoms:
- Latency and market impact as your orders are sent outside.
- Spreads widen, particularly around news or during late sessions.
- Slippage on market entries and stop-losses becomes more exaggerated.
- Requotes and rejections, rare before, start to show up in a noticeable way.
For many strategies, a few extra pips of slippage per trade is the difference between a positive expectancy and a losing one. The strategy hasn’t changed, but the execution rule has, at the broker’s discretion.
Which strategies are vulnerable to A/B switch
Not all strategies suffer equally. The ones most exposed to execution settings share a few common traits:
Scalping is perhaps the most obvious casualty. When your profit target is 3 to 5 pips, half a pip of slippage each way eats into your bottom line. As scalpers need consistent and low-latency fills, the A-book rarely provides this reliably.
News trading also degrades meaningfully as it tries to catch fast moves during high-impact data releases. It depends on near-instant execution and widened spreads will easily break the setup.
Tight stop-loss strategies such as breakout and momentum systems are vulnerable to stop-hunting on the B-book and to slippage on the A-book, losing on both ends.
Longer-term swing traders and position traders are generally more spared because their edge doesn’t live or die on a pip of slippage. Still, they’re not immune as swap rates and wide spreads on less-liquid pairs can quietly erode returns over time.
See How to choose a forex broker as a day trader.
What traders should watch for
If you’ve been trading long enough, you’ve likely developed some version of these habits already. If not, now is a good time.
Keep execution records. Log your average slippage per trade type over time. If it deteriorates meaningfully without a clear market explanation, something has likely changed on the broker’s end.
Test across multiple brokers. Running the same strategy across different brokers is one of the more reliable ways to isolate execution quality as a variable. Diverging results on identical signals is telling.
Read the fine print on order execution. Most brokers disclose their execution model, somewhere in their legal documents. Phrases like ‘acting as principal’, ‘internalisation of orders’ or ‘market maker’ tell you that B-booking is on the table.
Be sceptical of offshore brokers offering unusually tight spreads. The generosity often comes at a price that doesn’t show up until your strategy starts winning consistently.
Monitor your account behaviour after a strong run. If your fills noticeably worsen after a profitable streak, you’re probably being reassessed. It’s worth reaching out to your broker to ask about their execution model. The response, or lack of one, is itself informative.
Conclusion
The A/B book dynamic is one of the less-discussed realities of retail forex trading. Your strategy’s sudden decline may have nothing to do with itself, and everything to do with the order execution.
The traders who navigate this successfully tend to treat their broker relationship as part of their edge, not just a cost centre. They monitor execution and diversify across brokers where possible, and remain sceptical of conditions that seem too good to last.
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