The Mizuho Financial Group expects to pad its capital base by 1.2 trillion yen through the issuance of preferred shares, up from the initially planned 1 trillion yen, as more domestic corporate investors than expected have offered to buy shares, Mizuho sources said Friday.

The revised target will be approved at a board meeting Wednesday, after the latest stock market trends are studied and other considerations on investments are made.

Mizuho initially planned to float 850 billion yen in preferred shares to domestic corporate borrowers and life insurers, while issuing 150 billion yen in preferred shares to overseas investors. These goals were announced in January as a means of increasing loan-loss charges to 2.03 trillion yen from the 1.04 trillion yen estimated in November.

When the deal is complete, it will be the largest one-off capital hike ever by a Japanese company and will enable the group to prevent the huge loan-loss charges from devouring its capital base.

It will also cushion against the risk of being nationalized should any financial emergency take a swipe at its financial base.

The Mizuho group is operating under the command of Mizuho Holdings Inc., which was set up through the integration of three major banks -- Dai-Ichi Kangyo Bank, Fuji Bank and Industrial Bank of Japan.