How does a company with a market cap of just $332 million end up in the top 50 of the biggest companies by revenue, wedged in between a $57 billion company and a $42 billion one? It does big business in a volatile market. Shares of International FCStone, a large commodities brokerage, have fallen by more than 35% since the start of 2012. Sean O’Connor, CEO of FCStone, acknowledged that 2012 was a difficult year when it disclosed that earnings plummeted 60% from 2011. In order to turn things around, FCStone, which has historically been strong in grain commodities, is rapidly expanding its metals business.