Greetingz, system enthusiasts.
Why run a portfolio of systems?
1. Lower risk. If one strategy blows up, your other 99 probably didn't.
2. Volatility reduction. The individual strategies may make you want to vomit, but taken as a group you get a much smoother ride.
3. Position thresholds. Some stocks have a threshold where you exceed the book bid when you take a position. BZH seems to have about $50-100k during the day on the MM's book. I'm a small trader and would rather put $10k on 100 stocks rather than $1m on a single name.
4. All this is obvious to anyone managing a lot of money.
5. But for the amateurs out there (myself being nothing more than an engineer with a trade console, a couple years discretionary experience, and a small library of system trading books), here is another example. Following the theme of this thread:
Latest specimen: LCC (US Airways group)