Despite the rumblings a few years ago that the large-scale trading floor would become obsolete, most trading floors actually are retaining their footprints or increasing in size. But the constituencies on the floor are very different from what they once were. And surprisingly, traders are vastly outnumbered on most "trading" floors today.

For example, the equity group on UBS' floor, the largest trading floor in the world, is comprised of 600 people, but only 110 of those are traders. The remaining equities staff on the floor is comprised of sales traders, trade support teams, IT developers, quantitative analysts and other support employees. At many firms, positions such as compliance and legal staffers also are being integrated onto the trading floor.

Support positions have always been important. But technology and compliance positions, for instance, never sat alongside traders. The growth of electronic trading, however, has brought to light the critical need to have support teams on the floor and immediately accessible to traders. In addition, as the broker-dealer transitions to a role of buy-side execution consultant, it is essential that traders have access to all of the firm's service providers, such as algorithmic trading, quants, TCA specialists and technologists. Having an open floor housing all of these teams facilitates communication, which is being recognized by firms as critical to success.

Communication was a factor in creating the mammoth floor at UBS (featured in Advanced Trading's "Anatomy of a Trading Floor" photo gallary). "The open architecture design of the floor promotes integration across functions, seamless working relationships and virtually no line between the business, technology and management," according to a UBS spokesman.

A second trend fueling the growth of the trading floor is the creation of multi-asset floors, which enhance the need for more support positions on the floor, such as risk management and compliance. As multi-asset trading takes hold, trading floors are being created to group multiple assets, particularly products that correlate to each other. The idea is to create "pods" of various groups and functions that interrelate on the floor. At UBS, the 1,400-seat trading floor houses trading for all products. Other firms are establishing multiple large floors that each house groups of related products, such as cash and derivatives.

Yes, electronic trading has displaced a good number of traders. But from the looks of existing trading floors — and more important, the recent rush by broker-dealers to secure space to build new floors — the large and soon-to-be-even-larger trading floor still reigns supreme. And while they might be sharing space with various colleagues, the limelight still belongs to traders. Just take a look at our cover.