The sale of Grand Central to the owner of the Bullring and Martineau Galleries is to be investigated by regulators.
The Competition and Markets Authority (CMA) will review Hammerson’s £335 million takeover confirmed earlier this year over concerns it has hampered competition.
Hammerson is part of a consortium which owns the Bullring and also owns the giant Martineau Galleries regeneration site in the city centre.
As the deal to buy the asset from Birmingham City Council and Network Rail continues, Hammerson has now been ordered to run Grand Central as a separate business until the review is concluded.
It also has to inform the CMA of key staff who leave or join the Grand Central business or the Hammerson business and all substantial customer volumes won or lost.
Hammerson has long been one of the most prolific investors in Birmingham city centre, owning half of the Bullring and with a long-term investment in Martineau Galleries, which it bought outright for £28 million last year.
Grand Central opening
The Mail reported earlier this year that Hammerson had been criticised by community leaders for a lack of progress at Martineau Galleries.
Hammerson recently entered a 50:50 joint venture agreement with Canadian Pension Plan Investment Board for ownership of Grand Central.
Grand Central, which opened in September 2015, has a total of 435,000 sq ft of prime retail space, anchored by a 250,000 sq ft John Lewis department store.
Fat Face, Hobbs, The White Company and Cath Kidston are among the retailers to open at the centre.
A spokesperson for Hammerson said: “The CMA (Competition & Markets Authority) routinely looks at mergers and acquisitions. They have been in touch with us to obtain information about our acquisition of Grand Central. We are cooperating fully with the CMA and we are in the process of providing requested information.”