Quote from GermanTrader:
The whole reason I opened up a bank account with one of IB's banks is to transfer money around without wire fees. IB is a very profitable firm, partially from their denial of competitive interest on inactive balances. I would not move my money international just to make an additional grand per year on interest. Not worth the risk.
In a normal interest rate environment IB has competitive interest rates on cash. It is this low interest rate environment and their benchmark of Fed Funds that make their current rates not competitive with simple money market funds.