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

Sellers were out in force in the stock market today, as the Dow Jones Industrial Average (DJINDICES:^DJI) logged its fourth straight day of declines. Though its losses were modest at the beginning of the week, the sell-off became more severe in the last two days, when the index lost a total of 494 points. Unexpected weakness in China's manufacturing sector sent stocks lower yesterday and, as emerging markets currencies lost ground today, that bearishness accelerated as investors fled to safe havens like treasuries and gold. By day's end, the Dow had plummeted 318 points, or 2%, to end at 15,879, in what amounted to the worst day for blue chips since last June. 

Only three Dow stocks were immune from today's bloodbath, and Walt Disney (NYSE:DIS) wasn't one of them. Shares of the entertainment giant slumped 2.8% Friday, bringing its losses to nearly 5% in 2014. Walt Disney stock is only now seeing the ugly side of last year's stellar 49.5% rally -- the ugly side being the psychological urge many investors feel to capture profits on their biggest gainers. In fairness, Disney shares, trading at 21 times earnings, also have some room to fall before they become the darling of value investors. Being a $125 billion company can have its disadvantages -- it's harder for businesses to grow rapidly the larger they get. 

Surprisingly, Chinese social media platform Renren (NYSE:RENN) was largely insulated from today's madness, adding 1.9% in trade. Not coincidentally, Renren also just agreed to sell the remainder of its stake in Nuomi Holdings, an e-commerce site, to China's Internet search giant Baidu. Terms of the deal weren't immediately available, but Renren was able to fetch $160 million from Baidu back in August for a 59% stake in Nuomi. That transaction valued Nuomi at around $270 million, so assuming the same valuation, the remaining 41% would be worth about $110 million, a substantial influx of cash for Renren, which itself is worth about $1.2 billion.

Greek drybulk shipper DryShips (NASDAQ:DRYS), however, was anything but insulated from the market pullback today. Shares cratered 10.3% as a key gauge of shipping rates, the Baltic Dry Index, lost nearly 4% Friday. DryShips stock is more than twice as volatile as the overall market, and is largely at the mercy of the going daily rate to ship commodities and materials. Dryships also has quite a bit of debt on its books, making the stock all the more susceptible to downside risk.