When backtesting, how are commissions per million rounded? Could this be a bug?

Created at 15 Feb 2015, 14:46
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cprcrack

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Joined 15.02.2015

When backtesting, how are commissions per million rounded? Could this be a bug?
15 Feb 2015, 14:46

If I set Commission per Million = 9, and Quantity (Lots) = 0.1, the commission per order is 0.09, which is 0.18 round-trip. That works perfectly in cAlgo when backtesting.

However, if I set Commission per Million = 9, and Quantity (Lots) = 0.01, the commission per order should be 0.009, which is 0.018 round trip. However cAlgo seems to round 0.009 to 0.00, which is 0.00 round-trip. So I end up with all my trades without any commission, which vastly changes my scalping bot outcome.

My question is, how does the commission rounding really work? Does this depend on the broker or on cTrader/cAlgo platform? I'm using ICMarkets cTrader/cAlgo. What is the real commission I would have been charged? I suppose it's not 0...

PS: Take into account that this rounding issue does not only happen with very low commission (I invented 9 just for the example). It happens also with any other value such as 35 per Million.

@cprcrack
Replies

modarkat
16 Feb 2015, 09:40

If I set Commission per Million = 9

Where did you find broker with such commissions?

@modarkat

cprcrack
16 Feb 2015, 11:50

RE:
modarkat said:

If I set Commission per Million = 9

Where did you find broker with such commissions?


It's always a good idea to read the full post before making a question that is already answered in the original post.
@cprcrack

Spotware
18 Feb 2015, 11:41

It is a rounding issue in backtesing. Commissions must are rounded to cents using math round rules. Examples: 0.009 to 0.01, 0.003 to 0.00. We will fix this issue as soon as possible. Thank you for reporting it.

@Spotware
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