Southampton executive chairman Nicola Cortese has resigned from his post at the club.
The club made the announcement on their official Twitter feed, adding that a search has begun for a new chief executive officer.
Club owner Katharina Liebherr, who in a reshuffle becomes non-executive chairman, said: "With great regret we have accepted the resignation of Mr Cortese.
"He has done a wonderful job and we very much wanted him to stay. A search has now begun for a successor.
"It is business as usual and we will ensure that the manager, team and staff at the club have all the help and support they need."
Southampton FC announces that club owner Katharina Liebherr has taken on the role of non-executive Chairman. #saintsfc— Southampton FC (@SouthamptonFC) January 15, 2014