The move would come in the wake of heightened volatility in the Japanese government bond (JGB) market, with super-long yields having spiked to record highs last month reflecting investors' concern over Japan's worsening public finances.

There is no consensus yet within the BOJ, as some prefer to maintain the current pace on the view the bank should focus on reducing its presence in the bond market, the sources said.

A final decision will be made at the BOJ's next policy meeting on June 16-17, when the board conducts a review of a current tapering plan that runs through March and comes up with a subsequent programme for April 2026 onward.

The BOJ received a sizeable number of requests from bond market participants to cut its quarterly taper size to around 200 billion yen, minutes of its meeting on May 20-21 with bank and financial institutions showed on Monday.

Some policymakers see such views as a reasonable ballpark figure, the sources said.

That would be half the size of the reduction under the current plan laid out last year, at which the BOJ cuts bond buying by around 400 billion yen per quarter until March 2026.

"The balance of opinions at the meeting will be a crucial factor in the BOJ's discussions on the taper plan," one of the sources said. The sources spoke on condition of anonymity as they were not authorised to speak publicly.

The BOJ began tapering its huge bond buying last year to wean the economy off decades of massive stimulus, and breathe life back to a market made dormant by its huge presence.

Though the BOJ still holds huge amounts of JGBs, some market players are now worrying that the steady reduction in the bank's bond buying could leave them vulnerable during heightened market volatility such as last month's sell-off in super-long bonds.

While many market players expect the BOJ to maintain or slightly slow the pace of tapering beyond April 2026, the BOJ has been mum on what the new plan could look like.

Having ditched a bond yield control policy last year, the BOJ is in no mood to ramp up bond buying in the wake of recent rises in super-long bond yields as medium and shorter-maturity bonds, as well as bank lending rates, remained stable.

But the volatility seen in the super-long JGB market has heightened awareness within the BOJ of the need to ensure its bond tapering plans do not destabilise markets, the sources said.

"The BOJ won't react directly to the rise in super-long yields, but is mindful of the risk the move could affect the entire yield curve," a second source said.

The new programme is likely to cover a one-year period running through March 2027.

MILDER TAPERING EYED

The BOJ has lagged well behind its global counterparts in whittling down crisis-era stimulus, having only exited last year a decade-long, massive stimulus aimed at pulling the economy out of stagnation. It also ended negative interest rates last year, though short-term borrowing costs are still stuck at 0.5%.

While the BOJ also began tapering its huge bond buying last year, it still owns roughly half of outstanding JGBs.

At its upcoming review, the BOJ is likely to roughly maintain its taper plan for this year, which would see monthly bond buying halved to 3 trillion yen by March 2026.

If the BOJ were to cut bond buying by 200 billion yen per quarter from fiscal 2026, its monthly buying will fall to around 2 trillion yen by the March 2027 end of the business year.

That would roughly mesh with requests made by some market participants for the BOJ to reduce its monthly bond buying to around 1 trillion to 2 trillion yen, according to the minutes of the meeting.

Compiled by the BOJ's staff, the minutes of the bank's meetings with bond market participants is seen as reflecting its preferred approach on bond tapering, and thus offers clues on the bank's final decision, analysts say.

($1 = 144.0200 yen)