Softbank’s mobile unit is the subject of the second-largest IPO of all time.

The Japanese conglomerate on Monday announced it had gained clearance from the Tokyo Stock Exchange for its mobile unit, Softbank Corp, to go public for 2.4 trillion yen ($21.04 billion).

Softbank plans to sell more than 1.6 billion shares of the unit, giving the company an ownership ratio of 63.14 percent after the planned listing.

Demand for shares could also lead to an over-allotment, bumping the Softbank IPO amount up by 240.6 billion yen.

Softbank said in the filing that its enterprise value has been driven by transforming Softbank Corp from a PC software and broadband and fixed-line wholesaler to a provider of mobile communications.Softbank IPO

The conglomerate expects the IPO to ensure the respective roles and valuations of the two companies “will be clear”.

“Softbank Group is accelerating investments on a global scale, while Softbank [Corp] is a core company to the group’s telecommunications business,” the company said.

“It is hoped that each of the two companies will be able to provide information regarding their businesses to the market with greater clarity and thereby better respond to the various needs of investors.”

Softbank Group said that after the listing, it expects Softbank Corp and its group companies to continue pursuing further growth in the telecommunications business.

The expected date of the Softbank IPO listing is December 19, 2018.

Softbank IPO to Separate Mobile from Innovation

The Softbank IPO and a separation of the subsidiary will allow the group to separate its origins as a mobile network provider and its future as a leading technology investor.

The company has provided hundreds of millions of dollars in funding for its multiple technology investments and ventures over recent years.

These have recently included investments in ride-sharing players Uber, Didi Chuxing, Grab, and Ola; the acquisition of UK-based chip manufacturer Arm; backing for cybersecurtiy firm Cybereason; and cash injections for London-based creator of virtual worlds, Improbable.

The company also has a controlling stake in Aldebaran Robotics, which led to the formation of Softbank Robotics and the development of Softbank Pepper; and owns Boston Dynamics, developer of the door-opening robot dog.

Softbank also has a stake in Chinese internet giant Alibaba Group and previously owned a stake in Indian ecommerce company Flipkart before selling to Walmart earlier this year.

Alibaba holds the current record for the biggest IPO when it raised $21.8 billion in September 2014.

The Softbank Corp IPO could knock the current runner-up, the Agricultural Bank of China – which raised $19.2 billion in 2010 — into third place.

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