VfL Wolfsburg chief Klaus Allofs admits regrets selling Kevin de Bruyne to Manchester City.
Allofs concedes replacing the Belgian has been impossible.
Discussing De Bruyne and Ivan Perisic, now with Inter Milan, Allofs lamented: "Yes, economically it was right, even if we knew that we'd lose great sporting quality.
"We recovered in terms of revenue, but these transfers did not earn as much as we imagined.
"In retrospect, one must summarize soberly: We could not replace Kevin De Bruyne and Ivan Perisic."