Marks & Spencer has saved nearly £50,000 in a year's rates holiday for a Simply Food store here, the Belfast Telegraph can reveal.
The shop on Upper Newtownards Road in east Belfast qualified for the relief to help retail survive through lockdowns and the pandemic.
Lidl, Tesco, Asda and Sainsbury's have already restored funds which they saved on a full year's rates relief in the UK as a whole.
But M&S has said it will not be repaying the amount it has saved.
Unlike the rest of the UK, where all retailers qualified from a year's rates rebate, the NI Department of Finance had excluded food stores of more than 500 sq m. But the smaller-scale Ballyhackamore shop qualified.
All businesses here, including large stores, were given a four-month rates holiday early in the pandemic.
One resident described the store as "constantly busy," often with a queue at the entrance.
The department website gives the shop a net asset value of £90,700, which would leave its annual rates bill at £48,812.
An M&S spokesman said: "We are very grateful for the much-needed support Government has provided to businesses impacted by the pandemic - including ours. It has enabled us to support our colleagues and our suppliers, whilst continuing to serve our customers in what have been incredibly challenging circumstances."
M&S made a loss for the first time during last year, and has not paid bonuses or dividends. During the spring lockdown, sales were hit by the closure of departments like home and clothing.
And shops near travel hubs - such as a store close to Belfast International Airport - have also been badly hit.
But M&S is still selling goods like clothing, underwear and beauty products in some stores, despite the latest lockdown.
It has said it has closed floors selling non-essentials where possible - except where they are next to a food hall and shoppers have to walk through the department selling non-essentials to reach the food.
Glyn Roberts, chief executive of Retail NI, said future rates relief from the department "needs to get to businesses who need it most".
He added: "There were Retail NI members who were just over the 500 sq m rule that really did need the relief but didn't get it. It really should only go to business that need it the most and are struggling. All businesses should reflect on whether they need it."
He said the Executive should permit click and collect services for customers to order online or the phone, then pick up their goods at a given time.
The department announced in November that it is setting £105m aside to extend the rates relief scheme when it expires at the end of March.
A spokeswoman said: "Work is ongoing with the Ulster University Economic Policy Centre to identify those business sectors most severely impacted by the economic consequences of the pandemic." Regional rates for businesses have also been frozen for 2021/22.
But the department said it would be "illegal" to exclude small or mini-supermarkets from future relief on the basis that they were run by big chains like M&S. A spokesperson said retailers had confirmed that the original rates relief "has been essential to their survival".