Just to clear up something in my own mind...
Since some brokers and/or software has changed over to 5/3 decimal places and others haven't, I get confused when people talk in pips without specifically identifying their measure.
Are the recent discussions here re: Go and slippage in "old pips" or "new pips"? For example, a AUDUSD pip on my Go account used to be 0.0001 but now they have 5/3 digits so it is 0.00001 "Old pips" are ten times bigger than "new pips" or conversely, "new pips" are ten times smaller than "old pips".
In the recent discussions here, are we talking about slippage of 5 "old pips" (0.0005, or 50 "new pips") or 5 "new pips" (0.00005)? (Some people are calling these 'pipettes'?) If the latter, then I suggest that you have a close look at your trading system because a shift of 0.00005 is only half of one "old pip" which was for a long time the smallest change in price. (Personal opinion: If you think this is the difference between profits and loss then you are sailing very close to the wind, skating on some very thin ice, playing with dangerous fires, (insert other analogies here...) and "trading" whisper-thin margins is extremely hazardous to the health of your account, more akin to gambling in my view.)
Market forces do come into play here a bit too, and markets can be anything but rational. To see an example, set up a monitor like I did today and see how often the last digit in a price (bid) is a 3 or a 7. I did a recording of part of a session today and the distribution of the last digits was (quite) unexpected. 0 and 5 were most prevalent by a considerable margin (not entirely unexpected) but 3 and 7 were the least common, 4 and 6 were also relatively sparse (meaning that whilst I was watching most of the prices were in the range 8,9,0,1,2. Without having recorded the order of events, it then makes some sense the fifth decimal of price could rapidly jump from 2 to 8 thru 5, or 8 to 2 thru 5 which is 6 pips (pipettes or new pips) slippage, even if the price pauses at 5 on the way through. If we assume this phenomenon was noticeable across the entire market, the broker is certainly not to blame; it is the onus of the trader to factor this possibility into their trading system.
But still, paying 5 pips in slippage in the new pricing system is still better than 1 pip in the old pricing system. What are people going to do when we get 6/4 decimal places? Complain about 5 "micro-pipettes" or 0.000005 ?
wabbit
P.S. As I type and drink wine, through Go, the max lot size on AUDUSD is 20 lots, so even if you traded the full 20 lots, 5 pips slippage (0.00005) represents about 0.0625% with 100:1 leverage or about 0.3125% if you have 500:1 leverage... either way, they're small margins.
[Sidebar: As there are still some brokers trading 4/2 digits, it makes me wonder who is keeping all the extra decimal places? It seems to me that'd be a sure-fire way to be making money :- the brokers themselves trade in 5/3 digits, but only allow their clients to trade in 4/2 digits; the broker rounding off (in their own favour of course!) and pocketing the difference?)]