Acording to Jeff Hwang the bankroll needed for PLO is a bit bigger than for NLH:

> While pot-limit Omaha can be an exceptionally profitable game, the
> fact that you will probably need a bigger bankroll to suppor playing
> PLO vs NL hold'em is  in itself a cost.

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[Jeff Hwang: "Pot-limit Omaha Poker: The big play strategy"][1]


  
  [1]: https://books.google.es/books?id=IfYn3HrWE4sC&printsec=frontcover&dq=Jeff%20Hwang:%20%22Pot-limit%20Omaha%20Poker:%20The%20big%20play%20strategy%22&hl=es&sa=X&ved=0ahUKEwihw4eCgernAhVH-YUKHSosAwMQ6AEIKTAA#v=onepage&q=Jeff%20Hwang%3A%20%22Pot-limit%20Omaha%20Poker%3A%20The%20big%20play%20strategy%22&f=false