One research analyst has revealed why he warned his clients to avoid buying into ride-hailing app Didi ahead of the company’s listing on the New York Stock Exchange last week.

“Our advice was not to partake in the offering,” Neil Campling, head of technology, media and telecoms research at investment house Mirabaud Securities, told CNBC’s “Street Signs Europe” Wednesday.

Didi raised $4.4 billion in its IPO last Wednesday, giving it a market value of around $68 billion.

But the company’s share price has tanked by around 25% since the listing as a result of Chinese regulators cracking down on the firm in its home market.

There have been questions around the Didi IPO for weeks as China starts to try to reel in some of its biggest tech firms, fearing that they’ve become too big and powerful.

Mirabaud Securities was concerned that Didi was listing with a lower valuation than what it was valued at in its previous private round, said Campling.

There were some other worrying signs, he said, pointing to questions around profitability, growth deceleration, and the “very short” three-day investor road show.

Another cause for concern was Didi’s variable interest entity structure, said Campling.

A VIE is an entity controlled by a company by means other than a majority of voting rights; dozens of Chinese firms including Alibaba and Baidu have used a VIE structure to list on U.S. exchanges.

“We have concerns over that not least because international investors are buying into a Cayman Island registered company, which is many steps removed from the underlying technology company that they want exposure to,” said Campling.

Didi did not immediately respond to CNBC’s request for a comment.

Chinese regulators forced app stores in China to remove Didi’s app on Friday while it conducts a cybersecurity review of the company that will focus on Didi’s data use. Didi’s main app was then removed from Tencent’s WeChat messaging service and Ant Group’s Alipay on Wednesday.

In its IPO registration filing, Didi said it is using data on its customers to give it a competitive advantage, mentioning the word data no less than 160 times, according to Campling. But China is concerned about how Didi has used data on Chinese citizens to grow its platform.  

“Beijing is saying you don’t own that data per se,” said Campling. “It’s not for your exclusive use.”

“China wants to foster competition amongst its big technology sectors and doesn’t want monopolies to hold excessive power,” Campling added.

Shares of other Chinese names that are listed on U.S. stock markets fell Tuesday, with Baidu and JD.com dropping around 5%, and Alibaba slipping almost 3%.