The big spenders have submitted a £40m bid for the striker, who is Diego Maradona's son-in-law. But City need to come up with another £5m to invoke his release clause from Atletico Madrid, says the Daily Mail.
Aguero, 23, is keen to move to City and is prepared to leave his new £5m home in Madrid. Aguero's agent Jose Segui is due in Manchester in the next 48 hours to persuade City to offer the additional funds.
A proposed move to Juventus broke down last month because the former European champions refused to up their £40m offer, while Atletico will not budge on their valuation and the terms of his release clause.
Segui will also tell the FA Cup winners his client wants £7m a year - well within their budget.