They are paying interest on some currencies and balances. Its not much, but much better than others. In AUD its more than 5%??? Bad luck with USD. LOL
See on their web site:
http://www.interactivebrokers.ca/en/accounts/fees/interest.php?ib_entity=ca
BM = Benchmark Rate
USD 10,000 0% (BM - 0.5%) 100,000 0.13% (BM - 0.25%) N/A N/A
AUD 15,000 5.25% (BM - 0.5%) 150,000 5.5% (BM - 0.25%) N/A N/A
CAD 12,500 2.067% (BM - 0.5%) 125,000 2.317% (BM - 0.25%) N/A N/A
CHF 12,000 0.492% (BM - 0.5%) 120,000 0.742% (BM - 0.25%) N/A N/A
EUR 8,000 2.457% (BM - 0.5%) 80,000 2.707% (BM - 0.25%) N/A N/A
GBP 7,000 2.5% (BM - 0.5%) 70,000 2.75% (BM - 0.25%) N/A N/A
HKD 78,000 0% (BM - 0.75%) 780,000 0% (BM - 0.5%) N/A N/A
JPY 1,000,000 0.027% (BM - 0.5%) 10,000,000 0.277% (BM - 0.25%) N/A N/A
KRW 100,000,000 1% 1,000,000,000 1.25% N/A N/A
MXN 130,000 4.72% (BM - 4%) 1,300,000 5.22% (BM - 3.5%) N/A N/A
NZD 18,000 4% (BM - 2.5%) 180,000 4.75% (BM - 1.75%) 1,000,000 5.5% (BM - 1%)
SEK 80,000 3.35% (BM - 0.5%) 800,000 3.6% (BM - 0.25%) N/A N/A