Well firstly if you do sell at the top it will no doubt be down to pure luck
.
So selling 'around' the high (or buying around the low) is really the best we can hope for without relying on luck.
A good strategy is therefore to move the stop up to below the either the previous day's low, the low of the last 2 days or the low of the last 3 days.
Also, look for really outside days (ie when the high-low range) is at least double if not x3 of the previous day's. In a situation like that I would sell 25% if not 50% on the close of the day then use the strategy mentioned above.
In fact I would argue that if your DON'T get those outside moves it's not a parabolic move, so I would say that on both of those charts below they have set the foundations of a parbolic move but as of yet cannot be defined as one. Parabolic moves are just not that common, if you want to see some classics and try and work on some strategies then look at the charts of the usual technology suspects from 1996-2000 because each of them has several parabolic moves.
Finally, realise that parabolic moves create another sort of problem which is hard for all traders to work with, the one of fantastic profits being suddenly dumped on you. This can mess with your head and so it's very important in my mind to have a pretty iron glad strategy of how to deal with them otherwise your emotions will likely get too greedy and as fast as those profits appear - they disappear!
I remember once may years ago when I shorted the BTP (the Italian bond) and the bank of Italy suddenly raised rates, the contract dumped about 3 big points in 5 mins and I was really shocked and just didn't know what to do (I was sort of new to the game). Hence I messed up the trade and took 50% of what I should have made if I had been working with a logical plan. It wasn't quite a parabolic move but the circumstances were sort of similar.
So being on the right side of a parabolic move is one one hand great but it does create a whole new set of problems which in the heat of the battle (and there's a lot of heat in situations like that) are not easy to deal with. Something to remember anyway.
