* Return on investments -10.03 pct or 9.667 trln yen loss
* Worst performance since fund began managing own portfolio
* Loss nearly halved in first quarter of this financial year
* Outperformed Calpers (Recasts, adds comments from fund, portfolio breakdown)
By Chikafumi Hodo
TOKYO, July 1 (Reuters) - Japan's public pension fund, the world's largest, said on Wednesday it posted a record loss of almost $100 billion in the last financial year, hit hard by the global financial crisis and a sharp appreciation in the yen.
But the fund cut the loss by roughly half in the April-June quarter, helped by a rapid recovery in equity markets, including a 22 percent gain for Tokyo shares since the end of March.
The comparatively conservative pension fund, which has 74 percent of its investments in Japanese bonds, also said it outperformed other large foreign pension funds such as Calpers, or the California Public Employees' Retirement System.
"I'm not trying to take the large loss for the financial year lightly, but I want to say that investing in the market means facing a large swings," Koichi Nojima, the fund's executive managing director told a news conference.
The Government Pension Investment Fund (GPIF) said the rate of return on its investments fell to minus 10.03 percent, or a 9.667 trillion yen loss, for the year ended in March.
By contrast, Calpers had a rate of return of minus 29.1 percent. Calpers held 19 percent of its investments in bonds as of end-March, while 56 percent were in stocks and 25 percent were real estate and hedge funds, the GPIF said.
It was the GPIF's second year of losses and nearly double the size of the previous year's loss, when its rate of return was minus 6.41 percent.
GPIF invests the reserves of national and corporate pension plans into foreign and domestic stocks and bonds.
Investments in Japanese bonds outperformed other assets with a slim positive return of 1.35 percent during the period, with a 870 billion yen profit.
But the pension fund lost heavily in other asset classes.
The rate of return on the GPIF's investments in Japanese stocks was minus 35.55 percent, with a loss of 5.06 trillion yen.
The rate of return in its investments in foreign shares was minus 43.21 percent, or a 4.85 trillion yen loss.
GPIF's foreign bond holdings posted a minus 6.75 percent return, or a loss of 621.3 billion yen.
The yen's strength especially against the euro also hurt the performance of foreign securities.
As of the end of March, the GPIF had about 117.6 trillion yen invested in assets.
Of the total, it had 73.94 percent in domestic bonds, including Zaito bonds, 9.69 percent in Japanese stocks, 7.72 percent in foreign stocks, 8.51 percent in foreign bonds and 0.14 percent in short term assets.
GPIF manages its fund in line with a model portfolio, which gives a 67 percent allocation to domestic bonds, 11 percent to domestic stocks, 9 percent to foreign stocks and 8 percent to foreign bonds.
The portfolio is allowed to exceed its model portfolio by a rise or fall of 6 percent for domestic stocks, 5 percent for foreign stocks and bonds, and 8 percent for domestic bonds.
GPIF is expected to draw up a new model portfolio later this year, but Nojima declined to comment on how this may look, saying that the government has not yet set a mid-term target plan for the fund. ($1=96.81 yen) (Reporting by Chikafumi Hodo; Editing by Edwina Gibbs)