Quote from Trader_Herry:
IB accrued interest
IB accrued interest (talking about the opaque and confusing interest rate explanation on forex):
http://www.elitetrader.com/vb/showthread.php?s=&threadid=64052&perpage=20
IB official explanation about interest rate charges on its website:
http://www.interactivebrokers.com/en/accounts/fees/interestMethods.php?ib_entity=llc
If you don't know why you have been charged for more than expected, the above may answer your question.
PS: Actually someone suggested IB disclosing the steps of how IB arrives at that interest charge in the statement (instead of just showing a figure). It reduces the chance of getting surprised by the charges/debts.