I work for a company that uses shopping trolleys for moving stock. These shopping trolleys are clearly marked as belonging to big chain stores. There is a shop next door that also uses such shopping trolleys, so some of the trolleys we use come via the other shop. Is it permitted for me to use these trolleys?
If the trolleys belong to a chain store, and they are being used without permission, it would be forbidden to use them, and there would be a mitzvah of hashavas aveidah in returning the trolley to their owner. You could call up the management of the chain store and inform them that their trolleys are being used, and then act according to their reaction (if they give their consent for the trolleys to be used, you can use them; if they do not give their consent, and plan to retrieve them, they must not be used).