Aeon Co., Japan's largest supermarket chain, had its rating outlook changed to negative from stable by Moody's Investors Service on expectations the nation's economy will slow and consumer demand will wane, the rating agency said Wednesday.

"The outlook change reflects Moody's concerns that Japan's slowing economy and weakening consumer spending is undermining consumer confidence," Mina Sawamura and Emiko Otsuki, analysts at Moody's in Tokyo, wrote in an e-mailed statement. "It also reflects concerns over whether Aeon can adequately restore overall revenue and profitability in a timely manner."

The downgrade of Aeon's Baa1 senior unsecured long-term debt ratings affects ¥20 billion of debt, Moody's said.