I'm looking at the US500 long butterfly expiring on Friday and i'm looking at the ES short butterfly also expiring on Friday. You can sell 1 ES 1950x1990x2030 butterfly for 7.60+ and buy 5 Nadex 1950x1990x2030 bitterly for 5.40. This is a 2.20 profit for every 1 x 5 and the trade is risk free. Nadex market makers continue to try and penalize the fly sellers.
Your max loss on the ES short butterfly occurs at 1990 and is 32.4 (40-7.6) or $3240 on a single ES butterfly. Your gain from the 5 Nadex at that point isn't something we can calculate without knowing what you paid for the individual legs, but the max it could be would be $2,000 in the highly unlikely event you paid nothing for the long legs and got $100 for each of the short legs since each Nadex contract can pay out at most $100 and you only have 5*4 legs=20 Nadex contracts. So unless I'm missing something its actually more of a risk free loss, i.e. little chance of a profit. Did you actually implement it?
es fly is short, max gain is at 1990... implemented and made a gain, used bullspreads on nadex, not binaries, maybe run the numbers again? thanks for the post.