Japanese mobile operator SoftBank plans to invest $1 billion in South Korea’s biggest mobile commerce company Coupang, in a deal that will be the country’s largest internet investment.

Coupang’s current investors include BlackRock, Sequoia Capital and hedge-fund investor William Ackman.

SoftBank didn’t disclose the size of the interest it will acquire but said Coupang will continue to operate independently and Nikesh Arora will take a board seat, Reuters reported.

Last month SoftBank chairman and CEO Masayoshi Son appointed the head of its US-based investment arm Arora as representative director and president of SoftBank, suggesting he could name him as a future successor.

Analysts at the time said the move could also be a signal that the operator plans to expand outside of Japan after its acquisition of Sprint in 2013.

Yesterday SoftBank announced it has increased its stake in Supercell, the Finnish company behind popular gaming apps like Clash of Clans and Hay Day, from 50.5 per cent to 73.2 per cent.

Since joining last year, Arora has overseen a number of investments in Asia, including the $627 million injection into India’s fastest growing and largest online marketplace Snapdeal and taking the lead in a $210 million investment in taxi-booking service Ola Cabs.

Japan’s third largest mobile operator also reportedly invested about $600 million in taxi app Kuaidi Dache (speedy taxi) — which is backed by China’s e-commerce giant Alibaba.

Coupang was set up in 2010 and now considers itself the Amazon.com of South Korea.

The focus on Coupang is part of a wave of interest in the country’s thriving m-commerce market, Reuters said, noting that Coupang’s biggest rival, Ticket Monster, counts KKR, Groupon, Canada’s largest pension plan and a subsidiary of Singapore’s sovereign-wealth fund Temasek Holdings as investors.