IB has added a risk premium for large margin balances.
over $1,000,000 0.62% (BM + 0.5%)
over $3,000,000 0.37% (BM + 0.25%)
over $50,000,000 1.37% (BM + 1.25%)
"IB charges a higher default interest rate for large debit cash balances. If you anticipate consistently having a large debit...