NEW YORK, September 10, 2008 (AFP) - Ailing investment bank Lehman Brothers announced Wednesday an estimated 3.9 billion-dollar loss in its fiscal third quarter on further writedowns from the real estate meltdown as it took a series of restructuring actions.

The beleaguered Wall Street firm, seen as in desperate need for a cash injection to shore up its finances, offered no new plans on that front, but announced plans to restructure to slash its exposure to the real-estate sector.

Lehman said it would generate additional capital through the sale of a majority stake of around 55 percent in its investment management division.

The firm also said it was 'formally engaged with BlackRock Financial Management,' to sell an estimated 4.0 billion dollars of its British residential mortgage portfolio.

Another step announced was the spinoff of its commercial real estate portfolio worth some 25 billion to 30 billion dollars.

The moves came after a meltdown of shares of the white-shoe Wall Street investment bank as hopes faded for an injection of fresh capital.

Those hopes for a 'white knight' were dashed Wednesday as South Korea's state-run Korea Development Bank announced that it had abandoned negotiations about buying a stake in Lehman Brothers.

Lehman shares tumbled 44.95 percent Tuesday to end at 7.79 and have plunged 88 percent since February.

'This is an extraordinary time for our industry, and one of the toughest periods in the firm's history,' chairman and chief executive Richard Fuld said.

'The strategic initiatives we have announced today reflect our determination to fundamentally reposition Lehman Brothers by dramatically reducing balance-sheet risk, reinforcing our focus on our client-facing businesses and returning the firm to profitability.'

Lehman announced its losses and restructuring a week ahead of plans, aiming to shore up confidence and avert the kind of meltdown of confidence that killed rival Bear Stearns earlier this year.

The investment bank also slashed its dividend to five cents a share from 68 cents, saving some 450 million dollars annually.

The new structure leaves Lehman with 'limited commercial real estate exposure,' in an effort to ease fears it could be hurt by a slump in commercial property expected following the collapse in the residential real estate market.

Lehman said its latest quarterly results include a markdown in value of 7.8 billion dollars in soured assets -- including 5.3 billion in residential mortgage-related positions and 1.7 billion in commercial real estate positions, offset in part by some other one-time gains.

It has eliminated approximately 1,500 positions since the beginning of the third quarter in an effort to contain costs.

The results come after an unprecdented 2.8 million dollar loss in the second quarter, the first loss since the investment firm went public in 1994.

Like other banking firms, Lehman suffered billions of dollars in writedowns and credit losses in the crisis triggered by the meltdown of the US high-risk subprime mortgage sector.

Lehman's latest woes came just two days after the US government announced its plan to bail out struggling mortgage finance titans Fannie Mae and Freddie Mac.