Major financial institutions booked ¥400 billion in losses on their Tokyo Electric Power Co. shareholdings at the March 31 end of fiscal 2010 as the utility's shares plunged amid the Fukushima nuclear crisis, industry sources said.

Tepco shares fell to ¥466 per share on March 31 from more than ¥2,000 before the March 11 earthquake and tsunami seriously damaged the nuclear plant and led to radiation leaks.

Life insurance firms and major banking groups have held a massive amount of Tepco shares as stable assets but are now expected to reduce the level.

Losses booked on Tepco shareholdings are estimated at ¥100 billion each for the top shareholder, No. 1 Life Insurance Co., and Nippon Life Insurance Co., ¥10 billion for Sumitomo Life Insurance Co., ¥5 billion for Mitsui Life Insurance Co., ¥4 billion for Fukoku Mutual Life Insurance Co. and several billion yen for Meiji Yasuda Life Insurance Co.

Losses on Tepco shareholdings are put at ¥80 billion for Sumitomo Mitsui Financial Group Inc., ¥50 billion for Mizuho Financial Group Inc. and ¥30 billion for Mitsubishi UFJ Financial Group Inc. Firms usually log shareholding losses when market share prices fall more than 50 percent from acquisition levels.