http://www.marketwatch.com/story/td-ameritrade-to-buy-thinkorswim-for-606-million
Ellis said Thinkorswim, with about 94,000 clients and $2.9 billion in client assets, has clients who trade, on average, 450 times a year. He said that drives about 60% of Thinkorswim's revenue.
"Each trade runs...