The biggest threat to luxury brands' rapid growth

The grass isn't always greener on the other side.

After years of fueling the growth of luxury labels, there are signs that the global high-end consumer is starting to cool—placing a renewed emphasis on the importance of the United States and its affluent shoppers.

Pedestrians walk past a Coach store in San Francisco.
David Paul Morris | Bloomberg | Getty Images

According to a recent report by KeyBanc analyst Edward Yruma, weakness in the global economy, a strong U.S. dollar and ongoing geopolitical issues are contributing to a slowdown among consumers who live overseas.

But it isn't just international companies that are vulnerable to the shift. As a result of these trends, analysts have recently lowered their ratings on U.S.-based retailers Tiffany and Ralph Lauren—which pull in a high percentage of their sales abroad—and lowered earnings expectations for Coach.

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"Within the international luxury [category], we highlight China, Russia, Japan and Europe as particularly important markets," Yruma said. "Given the recent macro headwinds in these markets, which are largely expected to continue into 2015, we think the global high-end consumer could be challenged."

At Coach, for example, Morgan Stanley analyst Kimberly Greenberger wrote in a note to investors that deteriorating international trends are expected to weigh on the company's fiscal second-quarter earnings results—compounding its struggles to regain popularity among U.S. shoppers.

She predicted that similar to Tiffany—which disappointed investors earlier this month when it said holiday sales decreased 1 percent year over year—Coach's earnings report, to be released Thursday, will indicate that a stronger dollar pressured its sales.

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Greenberger noted that the yen depreciated 12 percent year over year during the accessories company's second quarter; since Japan accounts for about 11 percent of Coach's sales, it implies a 1 percent hit on the company's sales.

"Additionally, while marginal compared to Tiffany's higher dependency upon foreign tourist spending, we believe the stronger U.S. dollar certainly won't help Coach's U.S. retail locations, which may partially rely on Asian tourist spending," she said.

And after growing between 20 and 80 percent every quarter for the past five years, Greenberger noted that China only grew 10 percent in the fiscal first quarter—a deceleration she expects to continue in the second quarter.

The Chinese government's crackdown on the "gift giving" of luxury items has caused some high-end brands to lose 40 to 50 percent of their business there, said Alison Paul, vice chairman and U.S. retail and distribution leader at Deloitte.

Read MoreCoach deal does little to solve brand's woes

Another name expected to take a hit from its international exposure is Ralph Lauren. Earlier this month, Janney Capital Markets analyst Eric Tracy downgraded his rating on the luxury label to "neutral" from "buy," citing in part "intensifying global headwinds" that could hurt the label's sales. He noted that 34 percent of its revenue comes from international markets.

"I think the softness in China, the struggles in Brazil and so on, the luxury brands are not going to be able to rely on the growth there that they have in the last few years," said Paul.

Luxury still thriving

Despite the changing landscape and a slowdown in sales, The Boston Consulting Group said in a new report that the luxury goods and services category will continue to grow at around 7 percent a year, "handily outpacing [gross domestic product] in many economies around the world."

According to the firm's calculations, consumers spent more than $1.8 trillion on luxury items in 2012, which includes the approximately $390 billion spent on traditional luxury goods such as apparel, cosmetics and jewelry.

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As part of its report, BCG measured the current luxury status and growth potential of the world's 550 richest cities as defined by GDP per capita, to project the potential demand for luxury goods in each location in 2017. More than 40 percent of the top 50 cities were in the U.S.; that compares to only 12 percent for China (including Hong Kong and Taiwan) and 10 percent for Western Europe.

"A lot of [luxury brands] are turning back to Western Europe and North America and I think that's probably appropriate," Paul said.

Strong buck big for US retailers: Pro

She added that the resurgence of the aspirational shopper—someone who will splurge on luxury goods, but doesn't have the income to buy pricey items as frequently as they may like—should give U.S. luxury sales a boost.

Still, that's not to say retailers can totally ignore emerging markets—or Europe or Asia, for that matter. Some companies are even seeing resilience in these regions, thanks to a business model that touches a sweet spot for consumers.

Farfetch, for example, is a website that handles the Web operations of 300 independent luxury boutiques around the globe. Andrew Robb, the company's chief operating officer, said that Hong Kong and China is one of its fastest-growing markets.

"When e-commerce is growing at three or four times the overall market rate, if you're focused on e-commerce, you're getting the market growth anyway," he said.