[UprightCreature]

The way I see it there are two cases:

1) Heads up pot: In a heads up pot both participants have an effective stack equal to the smaller stack as we all know. In this case ignoring blinds (which average out over multiple hands) there is symmetry and neither player has an advantage. However when a player is short stacked there is a higher chance of that player going all in at some point in the hand. There is no inherent advantage to this however once it happens there are no more decisions to be made in the hand. Without decisions a good player can no longer make better decisions to gain EV over his opponent, this is good for bad players and bad for good players but will never turn a losing player in to a winner. In summary there is no inherent advantage heads up.

2) Multiway pot: In a three way pot there are two effective stacks the smallest stack and the second smallest stack. There is an asymmetry here and thus the possibility of and advantage to one player or another. Whenever the smallest stack goes all-in he can no longer be forced out of a pot, however one of the remaining players may be forced out. Once a side pot has begun the player who is all-in has an EV for the main pot. If no one folds the all-in players long term return from the pot will be this amount. However if someone does fold the EV of the all-in player will either stay the same or go up it never goes down through the action of a fold by a third party. This results in an advantage to the short stack player. Some people will claim that the short stack also loses out on the chance to win a larger pot when they have a strong hand, which is true but they will also miss out on the opportunity to lose a large pot when they make a strong second best hand. This is a symmetric situation so there is no inherent disadvantage of going all-in as a short stack in a multiway pot. Just like in the heads up case when a player goes all-in they can no longer make decisions this is good for losing players neutral for break even players and bad for winning players. In summary there is an inherent advantage to going all-in in a multi way pot with action still to occur. I think it’s clear that the scale of this advantage is inversely proportional to the size of the short stack. The real question should be at what stack size this advantage becomes inconsequential. My feeling is that even at 3BB there is still a reasonable advantage to this as it’s not uncommon for a multiway pot to get capped preflop online. The advantage is probably pretty small at 5BB, but someone rat holing down to 5BB would be playing with less than that a significant portion of the time.


A low minimum buy in (5BB) does keep the bigger games open to some of the weaker players, but I can't think of any reason to allow people to rat hole back down to 5BB as they are already in the game.