How to calculate probability of GapTrade closing in profit?

The name of the title is a question which I asked myself many times until i decided to finally take action.

Below are two photos which I can provide video proof of if needed. I simply asked myself if a person would invest in a trade and hold it over the weekend when the pair has a strong chance of gapping against them, then why not stop the bleeding by hedging and opening a quick scalp for the gap, close it once the market opens, and hope the gaps fills so you can make even more profit? I find it amazing how a chart can show you what YOU want to see and with a little hard work, we can find same flaws, however many or few their are, which we can profit on. So my question has to do with probability but I think it is safe to say that with a gap of 40+ pips and a close at market open, i will be in net profit right?

You have the same position size at the same price in 2 different directions, how do you want to profit from that if I may ask? If there is a gap down, your sell position is in profit, but your buy position is in the loss for the same amount, so you´ve made 0. If you close one of them right after markets re-open and hope for the gap to be filled with the other, it´s the same as if you would have been flat during the weekend and would have entered directly AFTER the gap happened (so right at market open) and hoping for the gap to be filled. Your approach just costs more money, because you pay double the commission and double the spread compared to when you´d just have entered into one direction (against the gap as you say - and mind you, gaps are NOT always filled at all) right after the markets re-open. Makes no sense, rather the opposite, as you have increased your trading costs with your "hedge" trades. Sorry to say.

Thank you ery much for having taken the time to have responded to my message. However, the worse case secenerio which you describe is the reason why I took the buy and the sell for the same lot size. Me not having mentioned that many brokers have 0 balance protection will protect me from dwarfing the profits in the account which Gaps massive to the profit side.
Both accounts are 2.12 lot size.
Both accounts have the same balance 420
So in total I invested 840 into the trade.
If GU gaps 60 pips in either direction, that would be 60 times 21 = 1260 profit plus the 420 i invested. That would clearly be 3x times more than what the other account lost and since you have 0 balance protection, you know you wont be able to have a negative balance. 1260 is more than 840. I understand the risk of it not gaping, but what are the probabilities of it NOT gapping compared to if it had closed the week inside a 100 pip range?

Thanks for your reply too, but I still don´t understand how you want to profit from this setup. If you have a long and a short position with the same lot-size, you will have +- 0, regardless of the gap size. If the market gaps 100 pips upwards, your buy will be in profit, but your sell order will be negative by the same amount that the buy order just made. You´ve made 0, just like you would have had no position at all, however, you are trying to twist it. And if you instead plan to close one order after market open and let the other run, you could instead just have entered directly WHEN the market opens with just one order and would have saved the double spread and commission you´ve just paid to your brokers.

P.S.: Ah I understand it now, you want to abuse the negative balance protection of your broker. Oh will they be happy about that ;-) Rest assured that the one where you kill the account and cost the broker > 0, will go to their legal department for collection and will try to play the "force majeure" card (read the TOS of your broker, they all have that in there and also mention weekend gaps for that reason) and you will have your account closed of course too. Don´t think you can play such games with brokers, they will always win, I tell you from my own experience doing latency arbitrage a few years back. Beside that they will try to collect the money from you, you will go to a global blacklist that the brokers exchange with each other and will not be able to open any new account soon (and you will need a new one each weekend to keep that fraud method working).

You should have asked more experienced traders rather than asking yourself.

They would have explained why this is not feasible.

Brokers are not idiots that is why they have legal eagles to protect them from traders like yourself.

Why don't you just learn to trade and forget about how you might be able to create a scam?

I beg to differ. Not only is this possible, but the only deterance which was given was that I will be placed on a black list or that it is some how immorral or illegal. The way I have decided to trade this possible gap isn´t any different from how the brokers themseleves trade when they trade against their clients. Would it have made any difference on the result if Instead of opening two accounts under the same name, if I used one account from Austria, and the other from Brazil, with two different names? See my point? If not, the reality is there is nothing wrong with what I am doing, I was even told to read the TOS which proves it, but how do you know what the terms of agreement says, if you dont even know the broker I am using? lol All in all, many people simply post things to not have people gain interest in something which may actually work. My intent is not only on sharing something which works, but also sharing the information with everyone so we can all work on it together.
Why would this be a scam? I see the word is used freely on forums and I would love to know how what I have done in any way shape or form is a scam?

Sorry to say, but you are a rookie, you haven´t yet experienced what brokers will be capable to do if you cost them money and especially like this. I am in this game for 10 years (making a living from it) and have played "dirty tricks" like this too, just with latency arbitrage (had account with over 110 brokers back then). You´ll see what happens next if you are trying to cheat them this way, but I still wish good luck to you nevertheless - everyone has to make their own mistakes, I know that just too well as I didn´t listen to anyone either in my early years :-)

P.S.: It´s very seldom that GBPUSD (or any other major pair) gaps 60 pips. It´s usually in the 10 to 20 pips range (like today too). However, if brokers expect big weekend gaps, they´ll also increase the margin right before the weekend and liquidate your position if it exceeds the required weekend margin, so you´ll not be able to open a 2 lot position on a $420 account balance in such a case, but instead need to add more funds to hold the position, ultimately eliminating the possibility that one of them goes into the negative balance protection, even if the pair gaps big. This weekend brokers did not expect GBPUSD to gap big, that´s the only reason why you could have that position size over the weekend. And now one of your accounts did not go into negative balance as you´ve hoped, but instead, you are down the same amount as you are up on the other account, having you brought nothing except double the spread + commission paid to both brokers - and hence the brokers already won the first time over you, bravo :-) I told you, you will not be able to play such tricks with them, they´ll ALWAYS outsmart you, especially with such scammy trading ideas like yours. Do you really think that brokers are THAT stupid? If your idea would work, everyone would do it as it would be very easy money and brokers would die left and right.

Good dat everyone. After the gap in my favor. I have now decided to share all of my recommendations in real time.
I expect 75.171 to touch before a drop to 75.05 Aiming for 3.5% gain on this long.

You might want to reframe from typing so much before you take the time to do the research. Not only did GBPUSD gap, but I was able to close for profit. I have also noticed that your pessismitic view of the market is rather shameful, however, we draw our reaity based on what we have gone through. I laughed realy hard when yo mentioned above that the broker didnt expect a gap which is why they allowed me to open both positions prior to the weekend. That my friend is out of this world.
I also laugh at the fact that you call my trade idea scammy, when there is nothing scammy about it at al. What I simply showed you could be done with a best friend with different brokers, which will end up with a lopsided win once the market opens in the event of a huge gap. Do yo know many times a gap occurs when a new high or low is reached during the week?

Very near TP and up over 6% at this time!

Second recommendation of the day.
Buying NZDUSD

TP .68741
sl .68633

current price .68701