The firm that removed the Jenners sign from the building in Edinburgh insists there was "no mystery" behind its "disappearance".
Nicky Erskine, owner of Edinburgh Rope Access, said his team was asked to take down the gold-coloured lettering and worked for two days to remove it.
He said it was now being stored on the sixth floor of the department store.
The Jenners building owner said it was "shocked" its tenant, Fraser Group, removed the sign without authorisation.
Sports Direct billionaire Mike Ashley took over the Jenners brand when he bought Fraser Group in 2018.
Frasers Group has been asked for comment about the sign's removal.
On Thursday a spokesman for the Danish billionaire Anders Holch Povlsen, who owns the 183-year-old listed building, said they were "very surprised" by the sign's removal.
He told BBC Scotland on Friday: "We are fully convinced that the signage is part of the listed building and that removing it is in breach with our contract and local planning.
"We have not discussed any such step with Sports Direct, and certainly not given any authorisation to do so.
"We have since yesterday done everything possible to stop Sports Direct and we are in direct contact with the local authorities."
City of Edinburgh Council said it was also investigating whether the removal of the lettering was a breach of planning rules "given the historical significance of the building".
"We'll take action if appropriate," Neil Gardiner, its planning convener added.
The Jenners building has occupied a prime location on Edinburgh's Princes Street since 1838.
It was bought by Mr Povlsen - who is one of Scotland's biggest landowners - in 2017, reportedly for £53m.
Fraser Group is due to quit the building next month. Despite that the current owners will keep it as a department store as well as turn unused parts of the six-storey building into a hotel.
The Jenners building owner is currently in advanced talks with a new tenant for the department store.
Mr Erskine told BBC Scotland he had thought it was the end of the department store occupying the building for good when he was asked to remove the sign.
He said: "It was sour sweet for me because I'm a very proud Edinburger so to work on such an iconic building was very special to me, but thinking it was the end of the department store made me feel terrible.
"I feel relieved now to hear it is not the end of such an historic store."
He said it would take three days to return the sign to the building, but that he had so far not been contacted to refit it.
Anders Krogh Vogdrup - the director of AAA United, which owns the Jenners building - said: "We can only once again emphasise that the Jenners building of Edinburgh is an institution and, despite the changing face of retail, it is our aspiration that there will continue to be a retail store for as long as we are its stewards.
"Our involvement in the Jenners building, is first and foremost about helping to preserve a unique historic building in Edinburgh.
"Already when we acquired the building, we knew that it came with a great deal of responsibility. Jenners is an iconic building in Edinburgh, and we take the responsibility very seriously."