18-year-old Botafogo centre-back Doria is the latest South American to be linked with Spurs, but the report claims complex third-party agreements could push his valuation past €9m.
The teenage defender has already been capped by the national team, and a third party are currently negotiating with Botafogo to buy the player for €9m.
They then plan to offer him around Europe, with Porto and Benfica often the preferred destinations for companies seeking a return on their investment when it comes to player sales.
Botafogo will look to keep a percentage of Doria's economic rights, as well as the right to a sell-on clause.
But Spurs are keen to complete a deal directly with the Brazilian club, and the report claims Tottenham sporting director Franco Baldini is prepared to at least match the third-party bid.
Doria is highly-rated in Brazil, and Spurs now see him as the best young defensive prospect in the country.
International compatriot Marquinhos has been linked with the likes of Barcelona and Manchester City, but Baldini believes Doria is superior to the Roma defender.