The travel firm Villa Parade has gone into liquidation, owing customers more than £3 million.
The collapse of the up-market company is the largest in the travel industry since 2008.
Villa Parade dealt with properties in Portugal, Spain, Greece and the US.
Many people who had booked villas through the agency are waiting to hear if their deposits will be returned. Some villa owners had not been paid for bookings in 2013.
Villa Parade took holiday bookings in the weeks before it entered liquidation at the end of May.
In total, Villa Parade, through its trading company Air Parade Ltd, had incurred debts in excess of £6.5 million, of which £3.3 million was owed to holidaymakers, according to the insolvency firm O’Hara & Co in Huddersfield.
The company, which had been operating successfully since 1999, had claimed to be the third largest villa rental company in the UK.
Holidaymakers have called into question the role of the Association of British Travel Agents (Abta) which was said not to have monitored the situation despite having been warned by worried customers as well as a rival rental company.
Abta says it began an immediate investigation when it was informed on 9 April. A spokesperson said that all customers will be reimbursed either through their credit card companies or through Abta.
