Comparing Pacific Investment Management Co and Janus Capital Group probably hasn’t occurred too often in the past. Pimco is known for bonds; Janus for stocks. But the comparisons are inevitable now that Bill Gross is heading to Janus more than four decades after co-founding Pimco.

For one thing, there is the size of the two firms. Janus is just a fraction of the size of Pimco. To put that into perspective, consider this: The firm manages less money across all of its products than Pimco has in its flagship fund alone.