
It is thought that Montgomery is exiting after he lost out in a boardroom battle.
Montgomery's departure comes in the wake of Mecom rebuffing an approach from UK national and regional newspaper publisher Trinity Mirror.
Mecom confimed the departure in a tightly-worded statement to the City this morning.
It is thought that the board had previously been considering postponing an announcement of Montgomery’s retirement until a replacement was found.
Yesterday (Thursday) Mecom had updated the market with a statement saying "As previously announced, the Board confirms that David Montgomery will retire by the end of January. A further announcement regarding succession will be made shortly."
This confirmed a previous statement from the company saying Montgomery, who was previously chief executive of Mirror Group between 1992 and 1997, would exit when a successor was found.
Mecom, which endured a tough 2009 and was forced to dispose of businesses and make swingeing staff cuts to offset the downturn, .