The owner of Gourmet Burger Kitchen has said the brand recorded an operating loss of £2.24m in the 22 weeks ending 29 July 2018.
Like-for-like sales for the burger chain were down 10.6%, a voluntary performance update issued by owner Famous Brands revealed.
The update came after results for the 12 months to 28 February revealed operating losses for the year of £7.8m.
At the time the full-year results were released in May, Darren Hele, Famous Brands chief executive, said property rates, labour and food costs were all having an impact.
In the voluntary update Famous Brands added: "The GBK operation unperformed the board and management's expectations."
It added: "We are mindful that GBK's contribution to group profitability has taken longer than initially anticipated, hampered by the adverse trading environment."
The day after the voluntary performance update, which also addressed the results recorded by other brands under the group, was published, Famous Brands issued a cautionary announcement.
Referring to no particular brand the announcement read: "Famous Brands is giving consideration to strategic options relating to a subsidiary that may have a material impact on the price of the company's share price.
"Shareholders are requested to exercise caution when dealing in the company's shares."