In the movie at the start they give one envelope with 10k for buy ins to Molly, she hold the money and from time to time a player go to her to buy additional 10k. Molly is only pay with tips, but they never explain how the Molly Boss get profit for hosting the game.
My guess was he keep a percentage from the buy ins but later on the movie they say that is illegal move. Of course they also never say if Molly Boss was running a legal operation but Molly was very adamant she will be legal even paying tax and stay away from drugs and prostitutes.
When Molly start running her own game, a guy was losing a lot and keep signing in
for 100k at the end he owe 1.2 million and said he didn't have that amount of money. Even when later give a check for that amount.
So how she give credits to the players. If they don't pay she isn't like a mobster and doesn't have some muscle to send to collect. Even when she claim do some research on the players before invite them, i think is kind of naive.
Later in New York in another game with 3 million on the pot she said
If I couldn't pay one time, would be the end of the game.
and then:
B calculate 2% of the pot and take it off the table. Take comision on violation of criminal code 1955
Here again looks like she is allowing player play without put any money. But the most surprising is how the players allow croppier take money from the pot unless that was a rule before the game, not something you do in the middle of a game.