Over the past two months, the CMA has been examining whether the £3.5bn deal between the two West End landlords, which was announced in June last year, would lead to a 'substantial lessening of competition'.
Now it has concluded that the merger can go ahead, with the deal expected to complete on 6 March.
Shares in Shaftesbury Capital – the new name for the combined group – are set to start trading the following day.
The merger will result in Capco owning 100% of the issued share capital of Shaftesbury on completion. As a result, Shaftesbury shareholders will own 53% of the combined group and Capco shareholders will own 47%.
Shaftesbury Capital's combined portfolio will comprise approximately 670 mostly freehold buildings with around 2.9 million square feet of lettable space across approximately 2,000 commercial and residential units.
The portfolio is located in a number of vibrant, high-profile and high-footfall destinations across London’s West End including Covent Garden, Carnaby, Chinatown and Soho, close to its major cultural and entertainment attractions, employment locations and transport hubs.
About a third of the merged estate is retail, another third covers hospitality and leisure, and the rest is made up of flats and offices.