Although we don't believe in timing the market or panicking over market movements, we do like to keep an eye on big changes -- just in case they're material to our investing thesis.

What: Shares of Chinese Internet company SINA (Nasdaq: SINA) exploded today, rising 15% as of this writing.

So what: It looks as if SINA and Baidu (Nasdaq: BIDU) are benefiting from investors' disappointment in Renren's (NYSE: RENN) quarterly reported last night. SINA's shares have been crushed recently, and combined with a high short interest, crazy price swings can happen without news from the company.

Now what: With the market up today and the tendency of Chinese stocks to be volatile even on quiet days, I'll chalk this up to another head-scratching move. No reason to change your investment thesis, but if you were looking to buy in it might be tempting to kick yourself today. Before you do, remember catching a falling knife is almost impossible, and this may be a sign investors are ready to jump back into this stock meaning maybe, just maybe, shares are going to stop falling. We'll see if this holds up tomorrow.

Interested in more info on SINA? Add it to your watchlist.

Fool contributor Travis Hoium does not have a position in any company mentioned. You can follow Travis on Twitter at @FlushDrawFool, check out his personal stock holdings or follow his CAPS picks at TMFFlushDraw.

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