TOKYO -- Rakuten Group on Thursday said it is preparing to publicly list shares in online banking subsidiary Rakuten Bank in a move that would raise funds for its fastest-growing segment as the wider group incurs heavy losses on forays into telecom businesses.

The Japanese e-commerce group's board also decided to incorporate its new telecommunications solutions business, Rakuten Symphony, launched in August.

"Rakuten Bank believes that through the listing of its shares, it will be possible to carry out management with a more autonomous perspective, and to consider various growth and financial strategies, including its own financing," the group said in a release.

Profit at Rakuten Bank grew 6% on the year in the first half of 2021. In July, the bank reached its target of 11 million accounts and 23 million credit cards issued, while the securities segment logged 6.24 million brokerage accounts.

"The credit card business, which generates most of [the] financial unit's earnings, will remain a wholly owned subsidiary and core to the unit," analysts at S&P Global said. "Rakuten assumes that even after the listing, the bank will remain an important consolidated subsidiary as it expands its ecosystem. We do not expect any major changes to Rakuten's actual control over the financial unit."

Meanwhile, capital costs for the year-old Rakuten Mobile segment left the group with a loss of 65.4 billion yen ($590 million) for the first half of the year. Elsewhere, Rakuten's flagship e-commerce business lost ground to Amazon as its share of the Japanese market fell to 12.6%. Amazon took a 25.7% share.

A listing date has not been decided, the company said. Earlier this year, Rakuten raised 242.3 billion yen from issuing new shares to Japan Post Holdings, Tencent Holdings and Walmart.