Attanasio’s group initially bought a 15.9% stake in Norwich before their investment was raised in April, when they became joint majority shareholders.
The deal does not involve payment to Smith and Wynn Jones, both 83, and will see them step down from the club’s board they first joined in 1996.
They will become honorary life presidents of the club.
“Delia and Michael have always been clear that they would act in the best interests of the club when passing on stewardship of it,” the club said in a statement., external
“By structuring the agreement in this way the parties have secured the long-term financial security of the club.”
Norwich, who lost in the Championship play-off semi-final last season, began their new campaign with a 2-0 defeat at newly-promoted Oxford.