East Street Investments have completed their takeover of Charlton, the Sky Bet Championship club have announced.
The deal was announced for the first time at the end of November and was subject to approval by the English Football League.
Outgoing owner Roland Duchatelet had been trying to sell the club since 2017.
Duchatelet told the club's website: "It was vital for the long-term health of Charlton Athletic that this deal was completed at the very start of the January transfer window.
"It allows the new owners to commit resources to the football side in order to bring in new players who will help secure the club's position in the Championship."
New chairman Matt Southall said: "I have been fortunate to meet many of the dedicated staff who have served the club so loyally and diligently and whose love of Charlton Athletic shines through.
"Their enthusiasm is part of the reason why we are so confident of building something special now the takeover is complete."
He added: "This is a great opportunity for ESI and we are thankful to Roland Duchatelet and his team for giving us the chance to build on such strong foundations.
"Now, for us, the hard work begins. We already have plans in place to support (manager) Lee (Bowyer) and his staff over the next month."
Charlton are currently 19th in the Championship with just one win from their last four matches.
