Japan’s decades of ultra-low interest rates may reach a turning point on Wednesday, as the central bank debates the fate of its yield control policy, which is creaking under pressure as markets repeatedly break a limit set less than a month ago.

Any change to the Bank of Japan (BOJ) policy is likely to trigger sharp rises in the yen and long-term interest rates by fueling market expectations of a near-term end to ultra-loose monetary conditions.

But the market reaction could be even bigger if the BOJ makes no change to policy, prompting investors to rush to unwind positions they have built on expectations of a shift.

“If the BOJ keeps policy steady, that would be a surprise and could push up dollar/yen to around 130,” said Masafumi Yamamoto, chief currency strategist at Mizuho Securities.

“But the dollar/yen will probably come under downward pressure again as market expectations of tweaks to ultra-loose monetary policy won’t disappear,” he said. The dollar was trading around 128.60 yen on Wednesday.

While other central banks have aggressively raised interest rates to resist rising prices, the BOJ has kept long-term rates around zero, seeking stronger consumption and wage growth to accompany Japan’s unaccustomed inflation of the past year.

But with inflation exceeding its 2% target, the BOJ is facing its biggest test so far for yield curve control (YCC).

Introduced in 2016, YCC holds short-term rates at -0.1%, while its target for the 10-year government bond is 0% with a small tolerance band.

Under pressure from rising yields, the central bank last month shocked markets by doubling the tolerance to plus or minus 0.5 percentage point from the target, aiming to extend the life of YCC. The cap for the 10-year bond therefore became 0.5%.

The move backfired as investors took it as a prelude to further interest rate rises, unleashing heavy bond selling that broke the new cap for a third straight market day on Tuesday.

Some investors are betting that the BOJ will be forced to adjust, or even dismantle, YCC as early as this week on the view the central bank cannot sustain the massive volume of bond buying needed to defend the cap.

“The liquidity drain caused by the BOJ’s bond buying is reaching abnormal levels,” said Chotaro Morita, chief bond strategist at SMBC Nikko Securities. “From the perspective of investors and securities firms, there’s a growing feeling the BOJ could give up maintaining its current policy scheme.”

At a two-day meeting that will end on Wednesday, the BOJ is likely debating whether further steps are needed to keep YCC going and iron out market distortions caused by its bond buying.

Before the 10-year yield breached the 0.50% cap on Friday, BOJ policymakers hoped to phase out stimulus only after Governor Haruhiko Kuroda’s successor took over in April and when recent wage rises had taken hold nationwide, sources have told Reuters.

But whether the BOJ can afford to wait that long is uncertain.

Instead of fixing market distortions with its heavy-handed defence of the 0.5% yield cap, the BOJ is aggravating them, critics say. Market expectations of an early rate hike have boosted yields broadly, with eight- and nine-year yields moving higher than the yield of the 10-year note.

In considering the BOJ’s options, some analysts bet it will further widen the band and allow the 10-year yield to rise as far as 0.75%. Others expect the central bank to raise the 10-year yield target above 0%, change it to one targeting a shorter-dated maturity, or abandon it altogether.

The BOJ is in a bind. Further cosmetic tweaks could simply ignite market expectations of a near-term rise in interest rates. But raising or removing the yield targets would run counter to the central bank’s narrative that it cannot overhaul or phase out YCC before stronger wage growth accompanies rising inflation, which has so far been driven mainly by import costs.

In fresh quarterly projections due on Wednesday, the BOJ is likely to revise up its outlook for inflation, sources have told Reuters.

Business confidence among big firms polled by Reuters soured in January and core machinery orders slumped in November, a sign slowing global growth is weighing on Japan’s fragile recovery.

The BOJ is likely to announce its policy decision anytime between noon and 2 p.m. (0300-0500 GMT), followed by Kuroda’s news conference at 3:30 p.m. (0630 GMT).