Great post, thanks for sharing all of that. I have a hundred thoughts; will try to keep it to the most pertinent. "The first problem on the ME is the price range for busts are crazy." On this note, one of the busts I got last year was for such an insignificantly small amount; I think it was a 1-lot that I got for $1.15 and which, even after the bust, was trading for like 10 cents higher or something so my loss to cover was like $10 or something so minor it wasn't worth pursuing. "(ie these days a stock like Air Canada could have an indicated market of $20.50 at 9:29:59 and then it opens at $22." Funny enough, AC was one of my busts from Friday. What is the "indicated market" price? A specific price calculation, and if so, how is it calculated? Does it just look at the pre-open bid/ask prices or take into account pre-market trades on the underlyings? "Now, what do you think is going to happen when he calls the broker and says - "one of your customers sold some calls at $1.60 and we can cancel them if you like". The broker will say - what is the current market (say $2 bid). Well of course we will cancel and sell them higher (lol). Look at all the friends this guy can make (too funny)" Here's where alarm bells start ringing for me. Because, if memory serves, IB has previously told me "Hey, we have no say in the matter; we just get notified by the exchange that a trade has been busted and then our system reverses it." But the protocol you described has all kinds of discretion involved. You're saying the exchange and brokerage have a conversation the trader's not even party to and decide whether or not to bust a trade? Gee, I wonder what could possibly go wrong? Surely a brokerage would never have an in-house prop desk who might have a financial interest in whether a trade gets busted... "The sixth problem (last one I promise) is that client to client trades are all busted but for those pro/client trades- they can be price adjusted." This is interesting, because I have, on a few occasions, gotten trades "price-adjusted" rather than outright busted...but I never understood why that happened, or under what circumstances the ME will price-adjust...you make it sound like it's a specific feature that's explicitly made available to pro traders(?) But it's something I suppose I've been party to before despite not being pro, nor having made any specific request... "Now in fairness to the Exchange -these rules are published and they are not hiding anything" Eh...I'm not inclined to be so charitable. Their rules on busting state "the Bourse may adjust Trade prices or cancel any Trade...if it determines in its sole discretion that allowing the Trade to stand as executed may have a material, adverse effect on the integrity of the market...The decision of the Bourse in such matters shall be final." So sure, transparency is good and all, but not when it amounts to "we can basically do whatever we want, trader-beware." "The problem is that the risk of entering opening orders often outweighs the possible gains" I'm fast coming to the same conclusion. So I basically have to wait around a couple hours and hope an opening trade (that I closed 10 minutes after open) doesn't get busted and leave me with insane exposure? The rules I linked to above have somewhat reasonable time limits (e.g. a request for review must come within 15 mins of execution, and a decision within 30 mins of the request), but it's all couched in aspirational "the exchange will endeavor to etc etc" language. My biggest problem is with the outrageous lag: at some point, even small retail traders need to able to rely on the finality of an execution. "Can you imagine buying some puts on SHOP on the opening - then scalping it for .50 and then the stock falls $150 over the next couple hours and then your initial trade gets busted? It's almost as if the ME is saying - if you're right - then we can bust (lol). If you're wrong - have a nice day..... I have indeed noticed a general pattern of "hm, why does it seem like all of the trades I make near the open that move against me stand, while the ones in my favor get busted?" I thought I was being a little paranoid, but the sort of cozy MM/broker/ECN cabal you're describing is exactly what concerns me. Oh, and I answered my own Q about appealability; Bourse's rules state: "These [bust] decisions are final and cannot be appealed." Cherry on top and indeed the most Canadian operation ever.