As social media stocks have taken off, so have short positions in some of them, like, for example, Twitter Inc (NYSE:TWTR). LinkedIn Corp (NYSE:LNKD) has also seen its short interest rise, as has Zynga Inc (NASDAQ:ZNGA)

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LinkedIn short interest rises nearly 40%

Benzinga reports that short interest in LinkedIn Corp (NYSE:LNKD) rose almost 38% in the first couple weeks of February, climbing to nearly 5.2 million shares. That’s the largest number of LinkedIn shares sold short over the last year, and it makes up over 5% of the float. However, it will still take only about a day to cover all of those short positions.

LinkedIn Corp (NYSE:LNKD) shares surged between July and September of last year and then started declining in December. Today the stock is down another 3%, and clearly, investors have little confidence that the social network will turn this downward momentum around. In addition, shares have underperformed the broader markets, as well as Google Inc (NASDAQ:GOOG) and Facebook Inc (NASDAQ:FB).

Investors have probably also noted that LinkedIn’s 200-day and 50-day moving averages formed a death cross not too long ago. That basically means that the 200-day moving average rose above the 50-day moving average.

Twitter’s short interest just keeps climbing

Twitter Inc (NYSE:TWTR) shares took off starting right at the company’s initial public offering. Since then, short interest in the company has been growing and growing, increasing in every two-week period through the first two weeks of February. As of the middle of this month, 44.77 million shares were sold short, which is over 27% of the float. However, the number of days it would take to cover all of those positions fell under two.

Shares of Twitter Inc (NYSE:TWTR) have fallen slightly since the middle of last month, but they still remain up more than 24% since the company’s IPO. In fact, the stock has performed about the same as Google Inc (NASDAQ:GOOG) and Facebook Inc (NASDAQ:FB), interestingly enough.

Zynga short interest also rising

Short interest in Zynga Inc (NASDAQ:ZNGA) also increased earlier this month, climbing by about 45% to 45.15 million shares. This is a peak so far this year and also the second biggest number of shares sold short over the last year or so. However, it still is just 7% of Zynga’s float.

Shares of Zynga Inc (NASDAQ:ZNGA) have risen more than 53% over the last month or so, hitting a new 52-week high this week. This may be why short sellers have become interested in it since so many analysts have held negative views of it.