Shein, the Fast-Fashion Giant, Is Said to Have Filed for an I.P.O.

Shein, the ultrafast-fashion retailer founded in China more than a decade ago, has filed confidentially for an initial public offering in the United States, according to a person familiar with the plans for the deal, who was not authorized to speak publicly about it.

Some companies keep their paperwork for an initial public offering temporarily under seal so they can prepare for the offering out of the public spotlight.

Investors had largely expected Shein to make the move this year, after the historically tight-lipped company began to address a range of criticisms from consumers and politicians in an apparent attempt to change perceptions about its business and practices.

Any public offering in the United States is likely to invite significant regulatory scrutiny, particularly amid strained relations between the United States and China.

Shein’s plans for an I.P.O. were reported earlier by Chinese media companies.

In recent years, Shein has gained popularity among U.S. consumers, particularly teenagers and young adults, for its wide variety of low-priced trendy apparel and accessories. The company was reportedly most recently valued at $66 billion.

But Shein has also faced claims that it has copied designs and unevenly benefited from a U.S. trade rule that allows it to avoid paying custom fees. And reports linking the company’s cotton to Xinjiang — a region in China where, U.S. officials say, the government has exploited the labor of ethnic Uyghurs — have brought intense scrutiny.

In April, two members of Congress asked the Securities and Exchange Commission to require Shein, as a condition of its expected offering, to certify through an independent party that it doesn’t use Uyghur forced labor. The company has said it has “zero tolerance for forced labor.”

Shein also started a program a few years ago to collaborate with independent designers after the retailer was accused of stealing designs, and it committed to sustainability goals. It has also teamed up with Forever 21, the fast-fashion mall stalwart, which could lead to more Shein apparel in brick-and-mortar locations.

Not all of Shein’s efforts were well received. In June, a trip that it hosted for influencers at some of its warehouses in China was widely panned on social media as being tone-deaf.

A spokeswoman for Shein declined to comment.