Mizuho Financial Group Inc. on Monday raised its group net profit estimate to 720 billion yen for the current fiscal year from 440 billion yen following a Supreme Court ruling last week.

Mizuho Financial said it will book an extraordinary profit for the business year to March 31 after the top court ruled Friday that the government must return taxes levied on the Industrial Bank of Japan, the predecessor of Mizuho Corporate Bank.

The company left unchanged its income estimate of 2.9 trillion yen and pretax profit of 610 billion yen for the current year.

The top court invalidated the national tax authorities' imposition of back taxes on the IBJ in connection with its writeoff of nonperforming loans to a housing-loan company.

With the ruling, which reversed a Tokyo High Court decision in March 2002 in favor of the tax authorities, the government will have to return 222.6 billion yen in back taxes paid by IBJ in 1996.

Some 100 billion yen in interest on the tax payment must also be paid, on a calculation of interest rates of 4.1 percent to 7.3 percent.