Chinese stocks break a two-decade trend, and that could signal more downside

The Chinese stock market is getting wiped out. China's Shanghai Composite sank to four-year lows this week, while the so-called BATS stocks — Baidu BIDU , Alibaba BABA , Tencent 700-HK and Sina SINA — have suffered heavy losses this month. "There's been a very long-term uptrend that's been intact since 1996, and the recent price action on the Shanghai Composite is now violating this," Craig Johnson, chief market technician at Piper Jaffray, said on " Trading Nation " on Thursday.