The Bank of Japan may have wrong-footed bond bears once again, but investors have a message for the central bank: a shift in policy is inevitable.

UBS Asset Management and Schroders are shorting Japanese government debt on bets the BOJ will eventually be compelled to abandon its ultraloose stance even after it remained on hold Wednesday. Torica Capital also expects the central bank to fall in line with the global trend of normalizing policy.

"We see no reason to square up shorts,” said Tom Nash, a money manager at UBS in Sydney who has bearish bets on Japanese bonds. "The yield-curve-control policy is not consistent with the current economic and political landscape and will need to be dismantled.”