Real Sociedad president Jokin Aperribay says they'll continue seeking to fund squad improvements.
La Real are now in the final 16 of the Champions League.
Aperribay said: "La Real has solid accounts. Last year was not easy, but the transfer of Alex Isak helped us a lot.
"And we invest a lot in the renovations of young people, also those of Elustondo, Le Normand, Zubeldia, Zubimendi and Mikel Oyarzabal. And the additions of Brais Méndez, Take Kubo, Momo Cho and Sadiq Umar, plus Alex Sorloth on loan.
"All this meant a significant expense."