Rakuten Bank will likely hold back from actively buying Japanese government bonds until the central bank raises interest rates again, in the latest sign that an uncertain policy outlook is weighing on investor sentiment.

The lender, a unit of Japan’s e-commerce giant Rakuten Group, has seen its total deposits almost triple from five years ago to ¥11.7 trillion ($79 billion) at the end of June, as its online banking services attract more customers. While the deposits are dwarfed by those of Japan’s biggest lenders, Rakuten Bank’s fast-growing cash pool is pushing it to look for investments.

Japan’s sovereign debt looks out of the picture for now due to volatility in the market. The bank shied away from making any fresh JGB purchases for investment during the first six months of the year. It held about ¥617 billion of JGBs at the end of June that it bought to hold until maturity, according to the bank’s data.