Japan's record corporate bond issuance will likely slow down, but a boom in environmentally friendly debt could limit the downside.

Companies have sold ¥13 trillion worth of bonds this business year, which ends March 31, already the most ever with three months still remaining in the period, Bloomberg-compiled data show.

That red-hot pace of issuance probably will not be repeated in fiscal 2020 because borrowing costs may rise, while fewer notes will mature during the period, reducing corporate demand to sell bonds, according to underwriters.