around 2.5% p.a., which is unacceptable for a pegged pair. IB marks up HKD debit by 2% and USD credit down by 0.5% right? Not sure what rates you are subject to, but my overall account is about US$1mn and subject to rates listed https://www.interactivebrokers.com/en/index.php?f=1595
IB have a fx swap program but you have to make a minimum bet of 10MM to enroll in it.
https://ibkr.info/article/2815
