ZURICH, Oct 2, 2008 (AFP) - Swiss insurer Zurich Financial on Thursday said it had been hit by a charge of 275 million dollars (198.5 million euros) due to the collapse of Sigma Finance Corporation.

In addition, it said it was writing down about 45 million dollars on Washington Mutual's debt instruments. JPMorgan Chase last month took over Washington Mutual, a US bank, after it collapsed in the largest US bank failure ever.

Zurich had earlier revealed that it took a charge of 295 million dollars on its exposure to another failed US financial institution, Lehman Brothers.

'The total of these writedowns represents approximately 0.3 percent of total Group investments,' said the group, which added that the charge would be made in its nine-month results, which are due to be posted on November 13.

Zurich's Chief Investment Officer Martin Senn said the writedown had to be seen in the context of its total group investments of nearly 200 billion dollars.

'Given the extraordinary circumstances, we have not only taken a conservative view but are proactively disclosing impairments related to exposures in defaulting companies.

'We remain confident that our disciplined approach continues to put us in a good position to weather the current financial-market crisis,' he said.

Sigma is a limited purpose finance company that announced on October 1 it would cease trading, hit by the financial market turmoil.