An arts and entertainment venue is being put on the market as its owners consider the Grade II-listed building's future.
In January Stroud District Council said it would be reviewing all options for the future of the 183-year-old venue.
The authority is considering whether to keep it under council control, let another group run it, or to sell it.
The closing date for all bids to either run the Stroud Subscription Rooms - or to buy it - is 15 September.
'Gun to its head'
Councillor Doina Cornell, chairman of the group looking at the building's future, said any solution should improve its "cost effectiveness" and help keep it for cultural use.
"We are committed to finding the best way to secure the future of the Sub Rooms, and this is one of three options we need to explore," she said.
"No decisions have been made yet, and putting the Sub Rooms on the open market does not mean that we are selling it. It's just one of the options we are investigating."
But Julie Wickham from campaign group Support Our Subs says "it feels like the community has a gun to its head" and says the sale option "should be taken off the table".
"To say they'd explored every option and something couldn't be found [then] they could put it for sale," she said.
"By running it in tandem it feels very upsetting".
The "imposing ballroom and exhibition space" and "occupying a prominent position in the centre of Stroud" is being offered for sale at £600,000.
So far nine organisations have expressed an interest in running it and a decision will be taken later this year.