Skadden, Arps, Slate, Meagher & Flom and Simpson Thacher & Bartlett had the lead roles on the $1.2 billion initial public offering of Japanese e-commerce startup Mercari Inc. on the Tokyo Stock Exchange.

Shares of Mercari closed up 77 percent over the offering price, elevating the valuation of the flea market app to $6.5 billion on its first day of trading.

Tokyo-based Mercari is the first Japanese company to be initially valued at $1 billion; the Tuesday listing on the stock exchange’s startup board was the largest IPO so far this year in Japan and also the biggest tech IPO in the country since 2016, when messaging app Line Corp. raised $1.3 billion from a dual-listing on the New York Stock Exchange and Tokyo Stock Exchange.

Skadden corporate partner Kenji Taneda led a Tokyo-based team advising Mercari. Nishimura & Asahi Tokyo partners Kohei Koikawa and Kentaro Sugimoto were Japanese counsel to the issuer.*

Founded in 2013, Mercari operates a smartphone app that is Japan’s largest online flea market. The Japanese company entered the U.S. market the next year and launched in London in 2016. Also in 2016, the company raised $75 million in a funding round, giving it a valuation of over $1 billion, making it a so-called unicorn. It was the first time a Japanese pre-IPO company broke the $1 billion mark. 

Simpson Thacher Tokyo partner Takahiro Saito led a team representing the underwriters, which included Daiwa Securities Group Inc., Mitsubishi UFJ Financial Group Inc., Sumitomo Mitsui Financial Group Inc., Mizuho Financial Group Inc. and Nomura Holdings Inc. Mori Hamada & Matsumoto advised the banks on Japanese law.

*Updated 6/27: This story has been updated with the Nishimura & Asahi partners leading the deal.