What happened

Shares of Chinese e-commerce company Baozun (BZUN 1.28%) imploded Friday, falling 16.8% through the closing bell.

If you own shares of Baozun, you can blame Credit Suisse for that -- and also the Chinese government.

Man examines a stock chart superimposed on a Chinese flag

Image source: Getty Images.

So what

In a note out this morning, Credit Suisse "double downgraded" Baozun, tumbling the stock's rating all the way from "outperform" to "underperform" (i.e. from buy to sell).

Why did Credit Suisse decide to downgrade Baozun -- and so dramatically? As the analyst explains in a note covered by TheFly.com today, a Chinese boycott being organized against international apparel brands is hurting Baozun's business. Furthermore, the analyst sees "soft performance" at Alibaba's (BABA 0.09%) Tmall subsidiary, a Baozun client.

As if all that weren't enough, Credit Suisse reminds investors of the threat of "continuously tightening regulation" from the Chinese government, which seems perversely intent upon strangling its own most successful tech businesses.

Now what

Despite what the analyst says has been strong execution from Baozun itself, with sales up nearly 33% year over year in the most recent quarter for example, all of the above adds up to a "bumpy road ahead" for Baozun and its shareholders.

Based on today's selling, it looks like many of those shareholders have decided to head for the exits, and not go along for the ride.