The most valuable real estate in the world is not in London's Mayfair, New York's Upper East Side or Tokyo. Based on the seemingly unstoppable growth in trading profits at the top investment banks, their trading floors are worth far more per square foot than even the most ostentatious apartment a hedge fund manager can buy.

Trading revenues at Goldman Sachs jumped 22% to a record $7.7bn (€5.8bn) in the first quarter this year, and last week Morgan Stanley reported record trading numbers. But there is little in the banks' public filings that indicates or explains this performance.