Investors should start preparing for a return to normal Japanese bond trading, as the central bank will one day step back from its debt purchases, according to a senior government official widely known as Mr. JGB.

The Ministry of Finance has already started looking into a comprehensive review to ensure there’s sufficient depth and liquidity in the market, as it’s only a matter of time before activity is allowed to normalize once again, said Michio Saito, who heads the department that oversees debt issuance. Saito is known for helping implement reforms when he worked in the Japanese government bond market in a succession of roles from the late 1990s until early 2010.

"I don’t know when exactly, but the time will eventually come when the central bank is no longer the main buyer of JGBs,” Saito said this week in his first media interview after taking up his current post in June. "We need to think about what we can do to make sure the market is ready when it is led by private-sector investors again.”