On top of the £2.2m in wages, West Ham will pay up to £1.3m in a loan fee to the Italian parent club which will take their total outlay to £3.5m meaning the real cost will work out at £218,750 per week until mid-May.
The agents want their commission too adding another £350,000 to the final bill.
Inter Milan paid over £39m pounds for Mario from Sporting Lisbon but an option to buy has been set at just over £26m as part of the loan deal.
If Mario passes his medical and signs the contract in the next 48 hours the pressure will be on for him to repay David Moyes and David Sullivan’s £3.85m faith in him.