Trading in Swiss International Airlines shares has been suspended in Zurich ahead of what analysts see as a likely takeover by Germany's Lufthansa.
Swiss is yet to make a profit
The Swiss government - the airline's largest shareholder - is meeting on Tuesday to discuss the bid.
The state invested in the carrier after its formation in 2002 from the shell of collapsed airline Swissair.
A go-ahead will allow Lufthansa to make a 50 million euros ($66m; £35m) buy-out offer to small shareholders.
Swiss International, which is yet to report an annual profit, is worth about 500 million Swiss francs ($426m; £224m), based on current stock market capitalisation.
"The Swiss see it as a done deal," said the BBC's correspondent in Switzerland, Imogen Foulkes.
A takeover is being greeted with a mixture of "sadness and relief," she added.
"When the old airline went bankrupt it was a national tragedy.
"They have poured billions of dollars into it but it just hasn't done well and they know it can't continue like this."
Swiss International has asked for its shares to be suspended from trading until Tuesday when the government will inform the carrier of its decision.
The boards of Swiss International and Lufthansa are also due to hold meetings on Tuesday.
The government, Swiss banks, and the Zurich authority together hold around 50% of Swiss shares.
Corporate stockholders including UBS, Credit Suisse and Novartis, who have about 36% of the shares, are likely to receive a nominal sum from Lufthansa, having already written off their investment.
The government reportedly wants to secure a deal that guarantees the future of airports in Zurich, Basel and Geneva, and retain the Swiss brand.
Newspaper reports on Monday said Lufthansa would invest in two long-haul jets, creating new posts at the firm's Zurich hub, as part of any takeover.