BERLIN, Dec 13 (Reuters) -

Top Volkswagen shareholder Porsche SE expects to

write down 7 billion to 20 billion euros ($20.98 billion) on its

investment, it said on Friday, in the latest sign of how VW's

cost crisis has shaken investor faith in the carmaker.

It also expects an impairment on its investment in luxury

carmaker Porsche AG, majority-owned by Volkswagen, of up to 2

billion euros, based on analyst expectations for the two

companies.

Volkswagen AG, which is in the midst of tense negotiations

with unions over cost cuts at its German operations, was unable

to complete its financial planning for the year, forcing Porsche

SE to rely on analysts' expectations for its forecasts.

The investment vehicle, jointly owned by the Porsche and

Piech families, said it now expects its group result after tax

in 2024 to be "significantly negative", withdrawing its forecast

of 2.4 billion to 4.4 billion euros.

However, it still expects to distribute a dividend for

the financial year, it said.

($1 = 0.9534 euros)