* Quarterly earnings $0.32 a share vs $0.23 year earlier
* Revenue up 53 percent at $285.7 million
* Same-store sales rise 25 percent, but growth will slow
* Shares drop 9.3 pct on Toronto Stock Exchange
By Allison Martell
June 7 (Reuters) - Lululemon Athletica Inc said on Thursday it expected the blistering sales growth of its trendy yogawear shops to retreat in the current quarter, sending its volatile stock tumbling anew as investors again questioned its lofty valuation.
The Vancouver-based company, already a fashion phenomenon in its home market of Canada, is rapidly expanding in the United States, targeting its yoga gear and running apparel at young, professional women willing to pay premium prices.
While reporting a 25 percent sales increase for established stores in its first quarter ended April 29, L ululemon said growth in the current three months would likely ebb to a percentage in the low double-digit range.
Any sign that the chain's muscular growth might falter has spooked markets in recent quarters, and this time was no different. The stock dropped 9.3 percent to C$65.34 on Thursday afternoon on the Toronto Stock Exchange, though it is still up nearly 40 percent this year.
"It trades at a high multiple, it's a big growth story," said Sterne Agee analyst Sam Poser. "The Street got ahead of them, including myself, and you know, if it's not perfect, these stocks get hurt."
Lululemon, a rare Canadian retail success story in the U.S. market, inspires fierce brand loyalty, with fan blogs tracking every product launch. Bu t with a rich valuation, its stock has been subject to sharp shifts in sentiment.
The company is trading at about 39 times analysts' expectations for fiscal 2013 earnings, according to Thomson Reuters data, much higher than its competitors. Nike Inc is at about 19 times forward earnings, and Under Armour Inc is at 33.
Indeed, compared with similar stocks , a higher-than-average number of investors are betting Lululemon shares will fall. At the end of May, 10.8 percent of the company's free float was being borrowed for short sales - essentially a bet the stock will fall - according to data from Nasdaq.
While that's down from 14.9 percent at the beginning of the year, L ululemon still ranks in the top fifth of all U.S. stocks in terms of short interest, according to Starmine.