China’s leading courier firm, Shunfeng Express made its debut on the Shenzhen Stock Exchange on Friday, furthering the competition in China’s delivery market.

The delivery company went public through back-door listing on the Shenzhen Stock Exchange, its reverse merger partner Maanshan Dintai Rare Earth & New Materials Co. was officially renamed SF Express, as per the material company.

Analysts say the market valuation of SF Express is estimated at around 210 billion yuan (30 billion US dollars), making SF Express the biggest Chinese courier company by market capitalization.

The first day of SF Express stock reached its daily limit of 10 percent on the Shenzhen bourse, reaching 55.21 yuan (8.04 US dollars) at around 10:50 a.m. local time, about an hour and twenty minutes after Friday’s trading starts, and maintained at that price when trading hours ended at 3 p.m.

The listing comes as China's booming courier service sector booked 400 billion yuan (58.22 billion US dollars) in revenues in 2016. State Post Bureau officials expect the figure to grow to 500 billion yuan (72.78 billion US dollars) this year.

China’s courier sector has seen fast securitization since 2016. YTO Express became the first listed delivery company in Chinese market in October, and ZTO made its debut on New York Stock Exchange one month later.

Built-from-scratch CEO Wang Wei to employees: Say less, do more.

The move also makes Wang Wei, SF Express's chairman and founder, worth more than 148 billion yuan (21.54 billion US dollars), according to Sina Finance.

Built from scratch, the CEO is known for his humbleness in Chinese media outlets. The SF-Express CEO informed the public his responsibility during his the listing ceremony that he and his company isn’t the same anymore before they went public.

“From today, we cannot say whatever we want, go anywhere we want,” adding that the standard applies to him first, considering the company is now public.

He reminded his employee that, considering there is disclosure rules from China’s securities watchdog, that if he is not saying anything or doing anything, his employees should not say or do anything.

Talking about the enlarged responsibility his company now carries, he said “so let’s all say less and do more.”

(With additional reporting by Chen Chen)‍