Gourmet Burger Kitchen is the latest casual dining chain to reportedly be put up for sale amid the coronavirus pandemic.
Sky News reports that Famous Brands, the group's South Africa-based parent company, is working with Deloitte to find a buyer.
Calverton UK, which bought rival burger chain Byron out of administration in August with the closure of 31 sites, has expressed interest in buying GBK, according to Sky.
Such a deal could see the two businesses combined into one group.
Famous Brands, which also owns Wimpy, withdrew financial support for GBK in April.
The company bought the burger chain for £120m in 2016 with a view to grow the business.
But GBK struggled with losses and closed 24 sites after entering into a Company Voluntary Arrangement (CVA) in 2018.
Before lockdown the company employed almost 1,300 staff across 62 restaurants.
GBK was founded in London in 2001 by three New Zealanders, including chef Peter Gordon.
Deloitte did not respond to a request for comment.