Hi Kumo,
Personally I prefer a Sub Account; I see no difference with having a second account (which I also have, thus 3 IB environments now), except for that the Main and Sub Account(s) can be aggregated in the IB environment – especially in the (great) mobile app this can be convenient.
Notice that using IB’s mobile app, or TWS for that matter, requires additional small fees for the market subscriptions. If you don’t use the app/TWS then you won’t notice a thing of it.
In PRT you’ll need to pay “double” for everything. Thus PRT license and also the market subscriptions. Of course you earn back per trade (1 euro IIRC), and this applied per (sub-)account hence not aggregated.
Hope this helps !
Peter
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