Japan's investment fund for teachers has switched its focus to avoiding losses, predicting the best days are over for both stocks and bonds.

The Teachers' Mutual Aid Cooperative Society is bracing for an end to a bull market that propelled stocks to an 18-year high and pushed bond yields to a record low, Toru Higuchi, a general manager in the asset management department in Tokyo, said in an Aug. 3 interview. The fund, which oversaw about ¥780 billion as of March, has no plans to significantly adjust the about ¥150 billion invested in risk assets like stocks, currencies and hedge funds.

The assets it bought surged in value in the two years to fiscal 2014 as Prime Minister Shinzo Abe's unprecedented stimulus policies boosted markets and weakened the yen. Japan's 10-year yield at 0.4 percent has almost halved since Abe took office in December 2012, while the Topix more than doubled.