Peterborough-based Thomas Cook has been told it needs to find £200 million pounds to secure an emergency rescue deal.
Britain's oldest package holiday firm risks going bust if it fails to secure the money for its banks. If that happened, the Civil Aviation Authority would have to repatriate tens of thousands of holidaymakers who are currently abroad.
The company said it is in talks with stakeholders, including leading shareholder Chinese firm Fosun, to bridge the funding gap. The two firms have been negotiating since June this year.
In an update to the market, Thomas Cook said the fundraiser is expected to significantly dilute existing shareholders' stakes in the firm, with "significant risk of no recovery".
Earlier this year, Thomas Cook announced it would close 21 stores, including those in Colchester and Stevenage.