How to spot signs of a dealing desk model

[Shadow Trader]

Brokers either pass orders to the market (A-book) or take the other side internally (B-book), and many do a mix. A scalper's results can depend on which bucket the account falls into, and nobody announces it.

Signs sometimes cited by traders:

- Spreads that stay oddly smooth during volatile moments.

- Slippage that is very rarely positive.

- Stops that seem to get hit by wicks that other brokers' charts don't show.

- Account restrictions that appear only after consistent profits.

- Sudden changes in execution quality after a streak of wins.

None of these prove anything alone. A feed can be smooth for innocent reasons, and plenty of losses are just losses. But a cluster of several signs deserves attention.

The best defence is comparing with a second broker, ideally with a small account, to see if the same strategy behaves similarly. If the performance gap is large, that's information.

Has a gap like that ever appeared between two accounts running the same approach?