France Football says Mourinho was already the world’s highest-paid manager — both inside and outside the dugout — while at Real Madrid, with about £10m in salary plus £2m in sponsorships from brands like adidas and Braun.
But marketing experts believe his Premier League second coming gives him the chance to cash in further.
Charlie Dundas, managing director for REPUCOM in the UK and Ireland, told The Sun: “Mourinho is in a very small group of managers who are bigger stars than some of their players.
“The Premier League’s global reach is far greater than La Liga’s.
“Any brand he is associated with will get exposure across 10 months of the year in over 200 territories.
“You can’t buy that kind of advertising reach. With around six partners bringing in at least a million a year each, £20m is easily attainable.”