Ammon Lam is running an ultimatum game, in which a proposer decides what percentage of a Ṁ1000 pool to offer a responder, and then the responder chooses whether to accept that offer (letting the responder keep the rest) or destroy the pool:

The procedure given in the market description to select participants is as follows:

At market closes, I will use #FairlyRandom to draw a random number to select the proposer, and ask the proposer to propose how to split the mana (in the comments section). Then I will randomly draw a responder, and ask the responder to decide whether to accept the proposal (in the comments section). *I will restrict the proposer and responder sample to those will less than 200 shares in the market, so that the ultimatum game incentives are not distorted by too much.

This will resolve at the number of participants by Ammon Lam's count when they use FairlyRandom to select one.

If there are more than 100 potential participants, this resolves above the upper end of the scale.