Just when it seems as if Vipshop Holdings (VIPS 0.68%) is starting to lose its winning touch, the Chinese fashion discounter finds a way to get back in vogue. Shares of Vipshop moved 12.2% higher last week, an impressive feat after kicking things off last Monday by hitting a three-year low.

There was no company-specific news triggering the rally that thrust it back into the double digits after a brief dip below $10 earlier in the week. Momentum plays a major role in Vipshop's moves. The stock moved higher in each of the first four months of 2017, only to give back most of those gains after double-digit percentage declines in May and June. Vipshop stock had dropped in four of the five weeks -- and six of the past eight -- before last week's recovery. Vipshop carries a one-year beta of 2.07, making it roughly twice as volatile as the S&P 500.

Vipshop's homepage.

Image source: Vipshop Holdings.

Flash mountain

Vipshop offers online flash-sale deals on brand-name apparel and other accessories. The model has largely sputtered through the U.S. and Europe, but Vipshop has been making this work for years in the world's most populous nation. Vipshop is servicing 26 million active customers, 32% more than it was selling to a year earlier. 

In one exhilarating stretch for investors, the stock more than doubled in 2012, 2013, and again in 2014. The stock retreated in 2015 and 2016, but following last week's pop, it's now showing a slight gain so far in 2017.

The stock's springtime slide this year was triggered by poorly received financial results. Growth was strong during the first quarter, as revenue and adjusted earnings rose 31% and 28%, respectively. However, at least one analyst downgraded the stock as a result of the online deal maker's lukewarm guidance. Vipshop's outlook for the second quarter was calling for top-line growth decelerating to a 26% to 30% clip, but bulls can rightfully point out that it's the same guidance offered for the first quarter with revenue ultimately climbing 31% for the period.

Prospects for another blowout quarter seemed to dim three weeks ago when Deutsche Bank downgraded the stock, concerned about competitive pressures and industrywide discounting in June. The timing of the cautious analyst note -- coming just as Vipshop's quarter was coming to a close -- was problematic.

Vipshop won't report financial results until next month, but the stock will continue to rock up and down until we hear how the period actually played out. Investors should be used to this by now. Vipshop stock is many things, but one thing it doesn't do is stand still.