Derby's American owners have sold the English second-tier club to a local businessman who made a fortune through the "Candy Crush Saga" mobile game.
Former Detroit Pistons executive Andy Appleby fronted the takeover seven years ago by a group of Americans, including investors in baseball, basketball and hockey franchises.
Within months of their takeover, Derby was relegated from the Premier League and the team has stayed in the Championship since 2008.
Now life-long Derby fan Mel Morris, who bought a 22 percent stake in the team earlier this year, has become the sole owner. Morris stepped down last year as chairman of King Digital, the New York Stock Exchange-listed company which created "Candy Crush."
The annual "Rich List" published by the London-based Sunday Times estimates that Morris is worth 400 million pounds ($610 million).
Five Premier League teams are owned by Americans: Arsenal, Aston Villa, Liverpool, Manchester United and Sunderland.