Like most of the other names on this list, it's been a tough year for shares of Sina ( SINA). The Chinese social media network has slid more than 7% so far this year, underperforming the S&P 500 by more than 17% over that time period. And Sina looks pointed lower this summer. Shares have been in a downtrending channel since back in March, making an orderly decline as more and more investors decide to unload their positions in this stock. One important thing to remember about downtrends (unlike uptrends) is that they can occur for two reasons: either people hate the stock (and want to sell) or people don't care about the stock (and don't want to buy). The declining volume over the course of the downtrend points to the latter. The fact that shares broke down below an important former support level at around $50 indicates that any previous pockets of buying pressure have been taken out by what's been going on in shares. Traders looking for a shorting opportunity in Sina should look to sell a bounce lower off of trendline resistance. Just keep a tight stop. To see this week's trades in action, check out the Technical Setups for the Week portfolio on Stockpickr. -- Written by Jonas Elmerraji in Baltimore.