Sacyr, which teamed up with state-owned oil company PEMEX more than a decade ago in a bid to control Repsol, sold its shares on the market during the past weeks, a spokesperson for the company said on Monday.
He declined to say how much the sale was worth.
The company said it cleared a 563 million euro ($603.65 million) financial debt related to the derivatives on the shares.
According to financial data provider Refinitiv, the 2.96% Sacyr held in Repsol was worth 695 million euros as of Friday market close.
($1 = 0.9327 euros)
(Reporting by Inti Landauro and Tomas Cobos, Editing by Louise Heavens)