Japanese investors’ purchases of domestic government bonds climbed to the highest in 17 years in the fiscal first half, a move that some analysts said reflected an attempt by pension funds to rebalance their portfolios.

Net purchases totaled ¥18.8 trillion yen ($119 billion) in the six months ended Sept. 30, according to data released by the Japan Securities Dealers Association on Tuesday that was compiled by Bloomberg. Trust banks, which are often regarded as proxies for pension funds, accounted for almost half of the buying, while a third came from banks.

Trust banks’ bond purchases were likely driven by a “rebalancing by public pension funds,” said Keisuke Tsuruta, a senior fixed-income strategist at Mitsubishi UFJ Morgan Stanley Securities Co. in Tokyo. “Equity markets were generally strong in the first half, while the yen was also weakening, creating conditions that encouraged allocation shifts from equities into bonds both domestically and overseas.”Japan’s public pension funds have a set allocation for stocks and bonds. When there are price changes in these asset classes, the funds will rejig their holdings to maintain the allocation.

A sale of 20-year government bonds on Tuesday saw the strongest demand on record, adding to signs of robust appetite for domestic debt.

Separately, data from the Ministry of Finance showed trust banks’ trust accounts bought ¥10.1 trillion of foreign bonds in the fiscal first half, while banks offloaded ¥7.4 trillion of such securities, the most since at least 2014.

“With higher oil prices expected to push up yields, the thinking was simply that US Treasuries and European bonds would suffer, so banks sold them,” Tsuruta. said. On the yen side, banks bought JGBs rather reluctantly because “they still needed to earn some carry against their deposit base.”