The yield on the Japanese government’s 10-year paper traded negative yesterday for the 17th straight session. When Haruhiko Kuroda first announced his negative rate experimentation, the 10-year JGB was low but still safely positive, yielding 22.9 bps on January 28. It would be negative for the first time on February 9 right as the rest of the world started to perk back up, and then fall below zero on an apparently durable basis February 24. At the lowest point, the bond’s yield was -10.3 bps on March 8.

That raises the question as to who in their right mind is buying 10-year bonds at -10 bps? And why are they continuing to do so?

Part of the answer can be found in NIRP itself, as even the BoJ’s three-tiered system only penalizes “idle” bank reserves and only so far. Rolling out of the equivalent of the Japanese deposit account and into a government bond escapes that monetary “tax.” The fact that such an effort is pushing up to 10 years in maturity demonstrates serious distortion (as of March 17, the 15-year JGB is safely positive at 15.7 bps but that yield, too, is pushing lower).

To roll into such long maturity negative yields, however, defies somewhat the point of holding even inert bank “reserves” in the first place. It adds elements of risk into the mix that go beyond trying to find the least costly monetary nothingness. That suggests something else working in concert to Japan’s banks.

Trading in Japan for today (meaning March 18 on that side of the dateline) shows that “something” else. The Japanese bond market saw what Bloomberg describes as “panic buying.”

Investors at home and abroad can’t get enough 10-year Japanese government bonds, driving the yield to an unprecedented minus 0.135 percent.

Yields sank across the curve Friday after the Bank of Japan’s operation to buy long-term debt met the lowest investor participation on record, spurring what Bank of America Merrill Lynch strategist Shuichi Ohsaki called “panic buying.”