Chris Coleman has been sacked by Sunderland after overseeing their relegation from the Championship, while chairman Ellis Short has agreed to sell the club.
Coleman was appointed in November, signing a two-and-a-half year deal after leaving his previous post in charge of Wales, who he led to the semi-finals of Euro 2016.
But the 47-year-old, who has been linked with the vacancy at Ipswich Town, was unable to turn things around at the Stadium of Light as Sunderland suffered successive relegations to drop into the third tier for the first time in 30 years.
"Sunderland AFC announces that manager Chris Coleman and his assistant Kit Symons have been released from their contracts," said a brief club statement on Sunday.
"The club would like to place on record its sincere thanks to Chris and Kit for their tireless efforts in what has been a hugely disappointing season for everyone involved with the club.
"The club is unable to make further comment at this time."
Coleman became Sunderland's eighth manager in just four years but the club's new owner, Stewart Donald, will be searching for a replacement.
Moments after Coleman's departure was confirmed on Sunday, the club said Short had agreed to sell Sunderland to an "international consortium of football investors", headed by Donald, who relinquishes the ownership of non-league Eastleigh.
"All of us involved in this believe that Sunderland represents an extraordinary opportunity," Donald said.