http://finance.yahoo.com/news/Interactive-Brokers-Group-bw-881766783.html?x=0&.v=1 IBKR announced results on Thursday. The market making business is down quite a bit, ibkr explained it so: "Market Making segment income before income taxes was $5.5 million in the quarter ended March 31, 2010, an increase from the prior quarter but a decrease of 95% from the same period last year. Pre-tax profit margin was 7% in this quarter, down from 65% in the same period last year. Low actual volatility, relatively high implied volatility and narrow bid/offer spreads contributed to the decrease in market making profits this quarter." How do they make money on the market making? Are they trading against their own clients, like NITE? I'd really like to know. This is interesting: Last march 31, the avg ibkr account had $82k. This year, it has $120. Not a bad increase, but less than the market. For comparison, last year the avg amtd acct had $46, and this year is has $60. The amtd'ers aren't keeping up, or else amtd is going more downmarket and getting smaller accounts. I think the former explanation is more likely.