Rakuten Group has taken a step to list its online brokerage arm, as Japan’s e-commerce leader struggles to dispel concerns over its debt levels and ability to make mobile operations profitable.

Rakuten Securities Holdings has applied to go public on the Tokyo Stock Exchange, the company said in a statement on Tuesday. The move is part of a drive to speed up decision making at each of Rakuten’s various businesses, which range from online shopping to finance and wireless services, it said.

Billionaire Hiroshi Mikitani’s online retailer has seen its shares tumble to a 14-year low as its loss-making mobile business drains cash ahead of a wall of maturing debt. Since April, the company has listed its banking unit and sold shares in an additional offering in a bid to ease its financing woes.

A Japanese credit ratings firm downgraded Rakuten last month, while shareholder Japan Post Holdings said it will book an impairment charge on its stake.

Rakuten Securities will remain an important part of expanding the group’s ecosystem after its listing, according to the statement. No scheduled listing date has been set as the offering still has to obtain the exchange’s approval and pass an examination by the Japan Exchange Regulation.

Mizuho Financial Group’s main brokerage subsidiary bought about 20% of Rakuten Securities for ¥80 billion ($554 million) last year, in a deal that fueled debate over how valuable the unit might be. Analysts at Mitsubishi UFJ Morgan Stanley Securities said the price paid was too high.

Net income at Rakuten Securities gained 2.8% last year to ¥9.3 billion as its client assets under custody grew amid increased stock trading by investors, according to filings.