Norwegian's stock plunged 30 percent in early Tuesday trading as shareholders anticipated a dilution in their stakes and a big discount for the share sale, whose underwriters include shipping to oil services billionaire John Fredriksen.

Norwegian has shaken up long-haul rivals by offering cut-price transatlantic fares, but its rapid expansion has left it with hefty losses and high debts, leading it to shift recently to focus on cutting costs and bolstering its finances.

The company, which had net interest bearing debt of 30.1 billion crowns at the end of the third quarter, said on Tuesday preliminary 2018 earnings showed an operating loss of 3.8 billion crowns, which it hopes to turn around this year.

"We expect to be comfortable already in 2019, even if there will be seasonal variations," Chief Executive Bjoern Kjos said, when asked whether the company could soon turn a profit.

The planned rights issue showed, however, that there were currently no buyers for Norwegian, analysts at Bernstein wrote in a note to clients.

"The timing of today's announcement may point towards a faster deterioration of the underlying business than previously estimated. However, airlines only stop flying when cash runs out and if the company is successful in the rights issue, it can likely have enough headroom to continue - for now," they added.

Bernstein has an "underperform" rating on Norwegian shares, which opened down 30 percent at a near seven-year low of 98.36 crowns before paring losses to trade at 124.5 crowns at 1124 GMT, down 12 percent for the day.

Norwegian told a conference call it was still working on a plan, first discussed last year, to find a joint venture partner with which to share the ownership of its aircraft fleet, which would significantly lower capital expenditure.

Norwegian said last May it had received two conditional proposals for a takeover from IAG, but had rejected them because they undervalued the firm. IAG said last week it had abandoned its attempt to buy the Oslo-listed airline.

There are currently no discussions under way with potential buyers, Norwegian said on Tuesday.

The airline said terms of the rights issue, including the subscription price and number of shares to be issued, were expected to be announced on or about Feb. 18.

Norwegian said its CEO, chairman and some other shareholders had agreed to invest 610 million crowns in the share issue, with the remaining 2.4 billion jointly underwritten by a John Fredriksen company and brokers DNB Markets and Danske Bank.

Norway-born Fredriksen, whose investments also include world number one fish farmer Mowi, has an estimated net worth of $13 billion, according to business magazine Kapital.

Norwegian's 16,000 shareholders will all get a chance to invest, however, and so the size of Fredriksen's eventual stake is not yet determined.

(Additional reporting by Nerijus Adomaitis; Editing by Jason Neely and Mark Potter)

By Terje Solsvik and Camilla Knudsen