Japan's biggest life insurers plan to add to holdings of superlong Japanese government bonds (JGB) over the next five months, but are cautious amid risks for a hawkish turn by the country's central bank.

Nippon Life, Dai-Ichi Life and Meiji Yasuda Life were among those who said they aimed to buy the longest-dated JGBs amid the highest yields in a decade, but would not do so aggressively due to expectations for even higher yields as the Bank of Japan moves toward an exit from stimulus.

The companies revealed their midterm strategy updates for the fiscal year ending in March in interviews and news conferences over the past two weeks.