Why 30BBs is such a tricky stack depth to play

You don't get more edge the deeper your stack goes, some deeper spots are less profitable says Dara O'Kearney.

I write a lot about late registration and one of the areas where I get pushback is around the profitability of different stack depths. Typically you come in at a shallow stack depth, 20BBs or under, which good players assume means you are sacrificing a lot of edge. 

It is true that generally the deeper the stacks, the bigger the edge. A pro will win more against an amateur at 100BBs than 50BBs, they will even more at 200BBs, and so on. 

But not all stack depths are profitable the deeper they go. Stacks between 20-30BB should actually be less profitable than stacks of 10-20BBs. 

30BBs is the worst spot in poker

30BBs is a horrible stack depth to play and I typically avoid registering at this depth. Shorter stacks can resteal against you and you have to fold a lot of hands. Against deeper stacks you can't profitably reshove your stack, but making a standard reraise puts you in a terrible spot against a 4-bet as you can't call wide and often have to fold a big portion of your entire stack. 

10-20BBs is much easier to play, assuming you are one of the short stacks. You can resteal a wide range, but your opponents cannot call off a similar range because they have to worry about the bigger stacks acting behind them. I call this 'stealing fold equity' from the other stacks. 

Short stacks are super profitable because you get a great return on your investment and can play a wide range. In fact, the most profitable depth would be just an ante, assuming one player has raised the pot you will often find yourself in a 9-1 ROI spot with at least 20% equity. The BB/100 on that would be close to 100 BB/100. 

If you were to map out the profitability of stack depths, it would look like a U-curve. The shortest stack depths are very profitable as are the deep stack depths, but the awkward 20-40BB stacks are super tough to play. 

It just so happens that it is precisely this stack depth that you have to master to thrive in poker tournaments because that is what the average stack often is at most stages. 

Dara O'Kearney's new book GTO Poker Simplified is out now.