Arbitrage is the simultaneous purchase and sale of the same asset in different markets in order to profit from a difference in its price. Arbitrage is the practice of taking advantage of price differences for the same product in different markets.(b) The deposit of custodial moneys from an account held in the custody of the treasurer of state to facilitate settlement of obligations of the custodial fund. Airbnb rental arbitrage is the act of renting a property longterm and then rerenting it shortterm on vacation rental sites like Airbnb or Vrbo. First we need some definitions.