Holidaymakers using Hove-based tour operator Manos and Panorama were warned not to panic after its parent company announced losses of £910 million.
MyTravel also posted operating losses of £358 million, meaning its outgoings were almost £1 million more per day than its income.
In the wake of September 11, 2001, the company, which used to be called Airtours, announced 2,000 redundancies.
The firm said today no more job cuts were expected, while customers were assured their holidays were protected by law.
A spokesman for Manos and Panorama said profits were up in those divisions.
He told The Argus: "We have had a very profitable year - in fact it's our second most successful year ever.
"Other sectors of the UK business and worldwide have been hit, for example, by the Sars virus and terrorism.
"There are not going to be any redundancies here. In fact we are recruiting at the moment. The general feeling in the company is quite optimistic."
However, MyTravel chief executive Peter McHugh admitted: "2003 has been an extremely poor year for MyTravel."
He conceded the company had "significantly under-estimated" the extent of the restructuring required for the UK business but said progress had been made towards a turnaround.
Mr McHugh said he hoped the company would return to profitability in 2005.
He said: "I understand the anxiety that exists in the market place but there's no chance we are going to go down at any minute.
"The critical element is cash and while a loss of £910 million is a very large number, only a small proportion is a cash loss."
Keith Betton, of the Association of British Travel Agents said: "MyTravel is bonded with both Atol and Abta and so they are financially protected.
"Anything customers have paid will be protected by that. If they hadn't travelled then they would get their money back and could just book again with someone else.
"If they were actually away at the time they could just carry on their holiday.
"The main thing to understand is that there is protection and you are not going to lose your money, so there is no need to panic."
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