Rakuten Group is marketing a $500 million (about ¥70.1 billion) bond to bolster the Japanese internet firm’s struggling mobile unit, in a test of demand for a rare junk debt offering from the country and a borrower under financial strains.

Amazon.com’s competitor in Japan is expected to price the two-year senior unsecured notes early next week, according to people with knowledge of the matter.

The bond offering is gaining attention given the small, fledgling junk debt market in Japan, where weaker companies aren’t compelled to sell speculative-grade notes due to easy access to bank loans. The debt sale also comes after Rakuten reported widening losses for the third quarter and as it faces the risk of a credit rating downgrade.