The German government has rejected a request for 650m euros ($930m; £561m) of loan guarantees from Arcandor, owner of Karstadt and 52% of Thomas Cook.
The company had said it might have to file for insolvency on Monday if it did not receive government aid.
Earlier, German finance minister Peer Steinbrueck told ARD television: “a bankruptcy is not totally excluded”.
Arcandor shares fell 31% by late-morning. It is awaiting news on a separate request for 437m euros credit.
Arcandor needs financing because about 600m euros of its loans need refinancing at the end of the week.