Do dealing desk brokers have to lose if you win? Meaning, do they have the option to act as an ECN for certain traders if those traders are actually profitable? Or, if a trader is profitable, that means a dealing desk broker has to be losing money because of them, if what the trader makes is more than the spreads / commissions the broker makes from their trades? Because if it's the case that a dealing desk has to lose if you win, then how could anyone ever feel comfortable using one? And, why is it even legal for brokers to act as dealing desks? It's such a blatant conflict of interest.