Mizuho books fourth straight loss, keeps forecast

TOKYO, July 31 (Reuters) - Japan's Mizuho Financial Group (8411.T) reported an unexpected fourth straight quarterly loss on Friday, hit by losses on its stock portfolio and credit default swaps, but stuck to its full-year forecast.

Japan's second-largest bank by assets said its group net loss totalled 4.5 billion yen ($47 million) for April-June. It lost 588.8 billion yen in the year to March 31, and has now failed to turn a profit for 12 straight months.

The April-June results compare with expectations for a net profit of 23.2 billion yen, the average of two analyst forecasts. Most Japanese bank analysts do not give quarterly estimates.

Mizuho made a net profit of 133 billion yen in the April-June period last year.

Mizuho stuck to its full-year forecast for a group net profit of 200 billion yen, the smallest among Japan's top three banks.

That compares with an average estimate of 99.2 billion yen in a poll of 10 analysts by Thomson Reuters.

Japan's banks traditionally take stakes in their corporate clients to cement business ties, making them sensitive to stock market swings. The benchmark Nikkei average .N225, which hit a near 26-year low in March, rose 23 percent in April-June.

Mizuho's shares have fallen about 18 percent this year, against a 3.2 percent drop in Japan's banking index .IBNKS.T. (Reporting by David Dolan; Editing by Dhara Ranasinghe)