While Gucci and Louis Vuitton blame slumping sales on their upmarket drive they argue will help them regain some of their lost glory, there is growing evidence they are losing out to newer, more affordable luxury brands.

After years of rampant expansion, Kering and LVMH, Gucci and Louis Vuitton's respective parents, are finding the likes of Michael Kors are proving smarter at tapping the fast-growing middle classes, particularly in big markets such as China.

Emerging market customers - the industry's main growth engine - were previously ready to save up to buy traditional status symbols such as a Louis Vuitton 625 euro ($860) canvas bag, but now they are showing stronger appetite for new brands such as Michael Kors that cost less.

"Brands like Louis Vuitton are expensive, and I see it everywhere I go," said Saltanat Shamova, a 25-year-old Kazakh studying in London. "Michael Kors was best for me because the design was simpler and the price was affordable."

The New York-based brand embodies affordable luxury: giving consumers a taste of class without the high price tag.

Part of Kors' success is that its products subtly replicate the style of big luxury brands such as Louis Vuitton's cylinder Speedy bag and Chanel's quilted leather tote.

Kors' $300 Weston shoulder bag has the same fringed pompom and shape as Gucci's $2,650 Jackie shoulder bag.

Other fast-growing accessible fashion luxury brands include the more U.S. centric and feminine Kate Spade and logo-heavy Tory Burch, as well as the more sober and minimalist Furla in Italy and France's classic Longchamp handbag maker.

There are also France's Carven and Isabel Marant and the UK's Karen Millen.

Industry observers say China's rapidly evolving consumer culture, with government policies discouraging luxury gift-giving, helps explain the rise of these more affordable brands.

"The Chinese are discovering new, middle-segment brands, and the austerity measures in the country and crackdown on ostentatious spending mean they will want to spend less on bling," said Arjen Kruger, chief marketing officer of VAT-refund company Global Blue, which monitors global spending.

MOVE UPMARKET

This is a major issue for parents Kering and LVMH, which built their empire on the two luxury brands which still today make up the bulk of their profits and market value.

"They milked the cow so much that now there is no more milk," the CEO of a major privately owned French luxury brand told Reuters at Fashion week.

LVMH, which also owns luxury fashion brands Dior and Celine, has invested in more accessible luxury labels like Marc by Marc Jacobs, the cheaper line of Marc Jacobs, which makes up 70 percent of its total revenue.

But the brand's sales, estimated at up to $1 billion, pale in comparison with Louis Vuitton at more than 7.5 billion euros.

And LVMH is set to lose some of that growth when it floats Marc Jacobs, a move it outlined last year.

In the past few years, both Gucci and Louis Vuitton have been trying to become more exclusive, reducing entry-level products, strengthening their offer of expensive leather bags and putting the brakes on shop openings.

"It is a strategic choice to ensure the long-term desirability of the brand," Kering CEO Francois-Henri Pinault said last month.

PROBLEM IS DEMAND

Both Gucci and Louis Vuitton say their move upmarket explains why their annual sales growth has collapsed to low-single digits from mid-teens levels three to four years ago.

But it appears the problem lies more with demand for the brands in general and with the rising popularity of more accessible luxury brands than with the products they offer.

Analysts say Gucci and Louis Vuitton may have trimmed the number of entry-level products but that business still represents more than half of revenue, raising uneasy questions about whether their high-end business can sustain sufficient sales and profit growth longer term.

"The entry level of Gucci and Louis Vuitton is facing a lot of competition from new, more aspirational brands such as Michael Kors and Tory Burch, and the trend is likely to continue," said Makiko Zuercher-Hosaka who manages the 12 million euro Dynapartners Luxury Brands fund.

"At the moment, it is hard to imagine seeing Gucci and Louis Vuitton's growth rates going back to the previous mid-teens levels in the next couple of years."

And the market understands that.

LVMH and Kering are trading on forward multiples of 18 times and 15 times, roughly in line with the industry average of 17 times, while Kors, whose share price quadrupled since its 2011 flotation, is on 33 times.

Also, Michael Kors is forecast to continue growing at a rate of more than 20 percent in the next few years after having recorded annual sales growth of around 40 percent.

Analysts estimate Kors, with annual sales of around $3 billion, makes revenue in Europe of about $400 million, up from $50 million in 2011 - driven by high demand and significant investments in marketing and new shops.

Gucci and Louis Vuitton are not the only victims of affordable luxury brands. Mulberry (MUL.L), which issued a profit warning in January, saw its sales growth drop after raising prices.

Furla CEO Eraldo Poletto sees "big numbers in terms of business" in the accessible segment and points to the rising number of middle-class buyers in markets such as China.

Goldman Sachs estimates the number of middle-class consumers in China - defined as people with minimum annual income of $30,000 - will rise by 24.4 percent a year on average between 2010 and 2015 and then by 14.5 percent in 2015-2020.

Karen Millen, whose concept is cutting-edge fashion at affordable prices with dresses costing around 250 euros, said many of its customers were global travelers.

"Our customer is a confident, professional, urban woman who travels... We have a lot of Russians and Chinese shopping in Paris and Brazilians in New York," said Andrew Ware, Karen Millen's finance director.

Karen Millen has, like Kors, stepped up investments, multiplying by five its advertising budget in the past 12 months, opened around 35-40 shops a year and is currently running a network today of around 376 stores.