Juventus have confirmed that Alessandro Matri, Fabio Quagliarella, Simone Pepe and Marco Motta have now been signed outright for a total of €37.25m.
All four players spent this season on loan in Turin with the option to buy on a permanent basis at the end of the campaign.
That right has now been exercised by the Italian giants, who have failed to qualify for Europe next term, at a cost of almost €40m.
Cagliari will receive €15.5m for the services of striker Matri who joined the Turin-based club in January.
Quagliarella, whose loan cost the Old Lady €4.5m, will hand over a further €10.5m to Napoli.
Meanwhile, Udinese will net €7.5m for midfielder Simone Pepe and €3.75m for right-back Motta.
Matri, Pepe and Motta have signed four-year deals with La Vecchia Signora, Quagliarella has penned a three-year agreement.