Mizuho Financial Group Inc., which has raised $4.4 billion (¥439 billion) since December, may need another ¥1.38 trillion to strengthen its capital, UBS AG has said.

Mizuho would need to raise that much to reach a core capital ratio of 4 percent, Nana Otsuki, a Tokyo-based analyst at UBS, said in a report dated Monday. The bank's ratio, a measure of financial strength that excludes preferred securities and preferred shares, is about 1.7 percent, according to the report.

The global recession has forced Japanese banks to write down the value of their investments and raise more than ¥5 trillion to restore their balance sheets. Analysts at Goldman Sachs Group Inc. and Macquarie Group Ltd. have also said Tokyo-based Mizuho may need more money.