Struggling carrier Swiss International Air Lines has asked for trading in its shares to be suspended on the Zurich stock market.
Swiss may be in need of rescue
The move has heightened speculation that the airline is on the verge of announcing a potentially life-saving tie up with another carrier.
Swiss said it had requested the suspension until 1200 GMT on Tuesday.
Speculation has focused on two possible scenarios for Swiss, involving either a takeover by Lufthansa or a tie up with the 'One World' alliance led by British Airways and American Airlines.
Swiss said it would make no further comment, but aviation analysts are now expecting a press conference on Tuesday.
Swiss International was formed out of the collapse of Swissair when its regional airline Crossair took over the management of the group.
The failure of Swissair provoked a sense of national trauma in Swizterland.
The Swiss government stepped in to broker a survival package in autumn 2001. It persuaded the airline's banks to extend fresh loans and Swiss firms to give up tax concessions so funds could be diverted to the airline.
But Swiss International's business has not gone well since then, and in June 2003 the airline announced it would shed 34 aircraft - one third of its planes - in an effort to save 1.6bn Swiss francs ($1.21bn; £725m).
It is dropping one third of its routes to streamline the business, and plans to cease flying to Washington DC, Beijing or Rio de Janeiro.
Swiss racked up a net loss of 333m Swiss francs ($240m; £149m) in the first half of 2002.
Swiss is known to have held talks with both Lufthansa - which heads the Star Alliance - and the One World grouping.
Analysts think a deal with Lufthansa would probably mean the end of Swiss as a separate airline.
Swiss' shares closed on Friday at 16.85 Swiss francs (US$12.32).