The Bax Limit Theorem

[SGspecial]

I was going through Bluff magazine's database of tournament results, and happened to check out the stats for Johnny Bax on Stars. The guy is obviously one of the top online players, and his overall ROI backs this up. The wierd thing is that his performance isn't consistent over all buy-in levels. He is killing the game at $100 BIs and under, but above that he is leaking like a sieve. This is not some sample size issue, this is over 400 tourneys at those levels since 1/1/06. I don't believe it has anything to do with field size either, since he is playing all sorts of field sizes at every level.

The question is, why does he seem to reach his "limit" at $150+ buy ins?