TGI Fridays has entered administration, putting jobs and restaurants in Hertfordshire at risk.
The American restaurant and cocktail bar chain has sites in Stevenage Leisure Park and two in Watford, in the High Street and on St Albans Road.
All three diners among the 87 put up for sale by owner Hostmore, with more than 4,500 jobs at risk across the UK.
Despite entering administration, TGI Fridays "continues to operate normally and all existing stores remain open".
The hospitality company has struggled with debt and heavy losses, but hopes to complete a sale by the end of September to keep brand running and help to secure jobs.
However, even if all sites are sold, the firm has said the money raised is unlikely to be sufficient to repay its debts in full, meaning it will be delisted from the stock exchange and wound down.
After failed merger talks in America last week, Hostmore, has seen its share price plummet, leaving it with a stock market value of less than £1 million.
Comments: Our rules
We want our comments to be a lively and valuable part of our community - a place where readers can debate and engage with the most important local issues. The ability to comment on our stories is a privilege, not a right, however, and that privilege may be withdrawn if it is abused or misused.
Please report any comments that break our rules.
Read the rules here