Is it permissible to work as an accountant for large retail stores that harm the local economy and small businesses and impose low prices on manufacturers?

There is no objection to working as an accountant or in any other capacity for large stores, even if small merchants are harmed by them, because this benefits the general public. Trade is based on mutual consent regarding the price and the item, except for what the ruler imposes in terms of pricing certain goods if the public interest necessitates it.