This doesn't seem a particularly appropriate forum to create this thread, but given the general nature of the topic, I couldn't find one more suitable.
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There is much discussion around the arbitrage that would occur if brokers offered prices wildly out of line with each other, but I have to confess, I don’t get how it would work in practise.

If someone (Broker-A) was willing to sell at a price lower than someone else (Broker-B) was willing to buy, I can see how you’d buy all you could get your hands on from Broker-A and sell it on at the higher price to Broker-B. Technically, you’re flat. But it’s not like a physical product where you’ve passed it on from A to B, you still have two open positions: A long with Broker-A and a short with Broker-B. You’ve locked in a profit on the deal but you’ve still got two positions open. How do you wind them down?

Also, the bid/offer presumably has to be ‘outside’ on either the offer/bid or bid/offer for this to be workable. If Broker-A is at 130.20/25 and Broker-B is at 130.10/40 no arbitrage is possible as neither is selling at a lower price than the other is willing to buy – Broker-A is ‘inside’ Broker-B. Have I got that right?