They both are straddle options! There is nothing called Half straddle options that you can find on the web or any options books, before today! Otherwise, which book, please? https://www.google.com.au/search?q=half+straddle+options&btnG=Search&client=firefox-b
Obviously I meant it this way: 1 stradlle is 1 call + 1 put... So if you buy 1 put + 50 deltas in stock it's the same size as half a straddle... Btw, Iv'e been an options market maker in Europe for 10 years, trading index options, single stock options, interest rate options... So yes... Obviously I have traded like that before....
185 strike Call position = 80 delta long Stock position = 100 delta short Total position = 20 delta short Which is the same as a 185 strike Put, with the same gamma/vega etc of the call... That's why, if you sell the Put... your position is: long 185 strike call short the 185 strike put = synthetic long underlying short 100 delta underlying... = completely risk free position. No gamma, no vega, no delta...
imo, a correct description of put call parity can be found here: https://en.wikipedia.org/wiki/Put–call_parity
You guys are obsessed with the option greeks .... so much so you can't see the forest through the trees. The original question is simple: Straddles, are they every profitable? The answer is simple: Yes they are ... if the underlying moves as you predicted. You guys can now get back to your option greek gobbly goop circle jerk discussion. Have fun.
I know, I just can't stand it when people start saying things that are incorrect... there's too many people following bad advice...
Deltas is used to measure options! http://www.investopedia.com/articles/optioninvestor/03/021403.asp Every single stock has 100 deltas, isn't it true!? Where can we find a stock (or futures) of 50 deltas to buy? Personally I can't! In other words, a straddle of "buying 1 put + 50 deltas in stock" would never exist/happen in real world trading!
Did I miss those in my years out? Oh, come on - in this context, the same strike/tenor and ATMFish strike, it's a totally ok to think it terms of premium paid. In fact, the moment you you live in a unit-tenor world, extrinsic premium is the best proxy to theta, which in turn is the best proxy to general risk. OK, Asian day is over and I am off to bed...