When Shein unveiled itself to the world at the height of its popularity several years ago, it touted a modern era for fashion — one built on speed, technology and an on-demand system capable of creating 4,700 new styles a day. Today, that model is increasingly looking like a relic. In the small factories that form the backbone of Shein's operations in China's southeastern manufacturing hub of Guangdong, there are no humanoid robots, quantum computers or state-of-the-art technology. Instead, there are dozens of workers toiling away in 10- to 14-hour shifts — in a way that, some say, feels almost like China of yesteryear.

"It represents the old tech, as opposed to the new tech," said Nirgunan Tiruchelvam, who leads the consumer and internet division at Aletheia Capital, an investment advisory firm focused on Asia. "Shein would have had a lot more traction with investors in the 2021 vintage. But the world has moved on from blockbuster e-commerce listings."

On Tuesday, investors largely agreed. Shares in Shein fell 6 percent in early trading, a humbling debut for a company once valued at $100 billion but now worth about a quarter of that. Its offering came after a wave of Chinese A.I. companies went public in Hong Kong and Shanghai, and years after Shein tried, and failed, twice in its efforts to list in New York and London amid opposition from officials and activists over working conditions at its facilities.

The drop in valuation reflects questions many investors have about the sustainability of Shein's business — and whether it can find new ways to grow after the United States and Europe, two of the company's biggest markets, ended tariff exemptions on cheap goods that had helped propel its low-cost model. Shein's offering comes weeks after shares of Unitree Robotics and CXMT — two companies that are driving the A.I. investment boom in China — skyrocketed in their public listings in Shanghai.