Investors can expect a weak start to the stock market today, as the Dow Jones Industrial Average (^DJI -1.29%) has lost 64 points in pre-market trading. World indexes mostly fell overnight, with European shares down by 1.3% as of 7:30 a.m. EDT, after fighting spread in Ukraine and new numbers out of China pointed to slower growth for the world's second-biggest economy.

Meanwhile, a few individual stocks are on the move this morning on quarterly earnings results, including Pfizer (PFE -1.07%) and Tyson Foods (TSN -0.05%).

Market movers
Pfizer today booked a steep 9% drop in revenue for its fiscal first quarter after sales were swamped by patent losses. The pharmaceutical giant booked strong growth from newer products such as Lyrica and Eliquis, but that boost failed to overcome the loss of exclusivity on blockbusters including Lipitor, which suffered a 71% sales dip in the United States. Still, Pfizer investors can be cheered by the fact that profit fell at a slower place then revenue, dropping by 5% to $0.36 a share. In a press release accompanying the results, CEO Ian Read also pointed to "the strength of our mid- and late-stage pipeline" as evidence that a return to sales growth isn't too far off. Pfizer affirmed its guidance for the full year, which calls for sales of $50 billion and earnings of about $2.25 a share. The stock was down 1.1% in pre-market trading.

Tyson Foods this morning announced record quarterly revenue results that beat analysts' estimates. The beef, chicken, and pork producer's fiscal second-quarter sales improved by 7.7% to hit $9 billion. Wall Street was expecting an increase of closer to 5%, to $8.8 billion. Earnings came in slightly lower than expected at $0.60 a share, but that still represented a massive 58% jump over last year's results. This quarter's improvement was driven by big gains in the chicken business: Tyson's chicken volume rose by 4.3% on strong demand. Beef sales also leapt higher despite a drop in volume, as a cattle shortage drove prices up by 13% in the quarter. The company affirmed its guidance for the full year, with CEO Donnie Smith saying in a press release that he is "confident in my expectations for the year that we will achieve our goal of 6%-8% sales growth." Tyson's overall forecast calls for production to rise by 1%, with profits getting a bigger boost thanks to falling input costs. The stock was up 0.1% in pre-market trading.