About 2,500 jobs have been lost and 64,000 bookings cancelled with the collapse into administration of Specialist Leisure Group.
The hotel and travel company included well-known coach holiday brands Shearings and National Holidays.
Trade organisation Abta said the company, which specialised in products for the over-50s, was “significantly impacted” by the coronavirus pandemic.
One hotel owner predicted its demise would leave “a void in the market”.
Abta said the company had struggled to provide thousands of refunds for cancelled trips.
It added that the vast majority of cancelled bookings were coach package holidays, which are financially protected, and customers with these bookings would receive a full refund.
The Specialist Leisure Group, based in Wigan, also operated Caledonian Travel and hotel businesses such as Bay Hotels, Coast and Country Hotels and Country Living Hotels.