NEW YORK — Nearly half of U.S. consumers shopped for apparel at Amazon.com over the past 12 months, according to a survey from Coresight Research, which concluded that Amazon is neck and neck with Target Corp. as the second-most-shopped apparel retailer in the United States (after Walmart), as measured by the number of ­shoppers.

Much of Amazon Fashion’s rapid growth has come at the expense of Target and Walmart, though department stores such as Kohl’s Corp., Macy’s Inc. and J.C. Penney Co. weren’t far behind in terms of seeing their apparel and footwear sales siphoned off by Amazon. Less affected were such off-price retailers as Nord­strom Rack, T.J. Maxx and Gap Inc., according to the online survey of 1,699 demographically representative adults conducted between January 18 and January 24.

“The biggest battles in U.S. retail are often characterized as Amazon versus Walmart and Amazon versus the department stores,” the report said. “However, our research suggests that Amazon versus Target may actually be the bigger battle, at least in apparel.”

Target is the top retailer that Amazon Fashion shoppers have switched some or all of their apparel spending from, according to the survey. Target apparel shoppers are also more likely than average to say that they expect to buy clothing and footwear on Amazon in the next 12 months.

Amazon’s expansion into apparel is one of the hottest topics in U.S. retail, yet hard data on Amazon’s share of the market is scarce, given the company’s limited disclosure on category sales, Coresight Research said. The research firm initiated its report to shed light on what apparel shoppers are buying from Amazon and how they view the retailer.

Coresight Research identified some of the project’s top ­takeaways:

• A large portion of Amazon’s apparel shoppers are Prime members, and about two-thirds of Prime members bought apparel on Amazon last year.

• Amazon’s private label ranges comprise the fourth-most-bought clothing or footwear “brand” on Amazon, even though the ranges are still relatively new. One in nine Amazon apparel shoppers surveyed said that they have bought Amazon private label ­apparel.

• Younger adult shoppers are looking for the full Amazon Fashion experience and are the age group most interested in trying Amazon’s apparel private labels and its Prime Wardrobe service. They are also the group most interested in the possibility of Amazon opening physical fashion stores.

• Amazon Fashion shoppers are satisfied with the site’s online experience and cited the ease of browsing and searching as the top reason to buy apparel on the site. Only 12% of shoppers think that the site could be made easier to browse.

• Amazon risks being viewed as an off-price retailer. Fully 48% of all Amazon apparel shoppers expect to always pay less than full price on the site, while only 12% shop on Amazon because its fashion ranges are up to date.

Notably, survey respondents who were Amazon Prime subscribers — paying an annual fee of $99 for free shipping and a host of other perks — were much more likely to have purchased apparel from Amazon than non-Prime members. Among Prime members, Amazon was the clothing retailer most had shopped at, while among non-Prime members, Amazon was just the seventh-most-popular place to shop for clothing and footwear.

Prime membership has grown rapidly; by one estimate, more than half of U.S. households now have a Prime account. “This implies that growth in Prime membership will underpin Amazon’s expansion into clothing and footwear. However, Prime membership levels are already high in the U.S., suggesting they could plateau in the coming years,” the report said. “So, Amazon may need to focus on driving up purchase frequency and average spend to support its market share gains.”