Sumitomo Life Insurance is taking an unusual step to avoid writing down losses on its debt assets, promising to never sell them while they are in the red, according to a person familiar with the matter.

The Osaka-based firm, one of Japan’s top-four life insurers, is taking advantage of guidelines for bond investors when prices move sharply. When there’s a 50%-or-more tumble in the market value of a bond from its acquisition price with no prospect of recovery, the drop in the debt’s value must be booked as a loss, according to Japanese accounting standards.

But if the insurer declares to an accountant that it will hold a bond until maturity unless it rebounds to its purchase price, it doesn’t have to record losses on the debt, according to those guidelines.