Stock Market Today: Apple Storms Into China, Costco Slows Down

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.

Expect a flat start to the stock market today, as the Dow Jones Industrial Average will fall by an insignificant eight points at the opening bell, according to index futures. Apple dropped some big news on the market about its foreign business, while Costco logged a slowdown in sales growth. Meanwhile, Dollar General continued its impressive retailing run in the third quarter.

Starting with tech, it's official: Apple is coming to China Mobile. The company finally signed a deal to get its iPhones onto the massive foreign network, The Wall Street Journal reported this morning. With more than 700 million subscribers, China Mobile represents a huge market opportunity for the Mac maker to boost smartphone sales abroad next year. The deal should also help Apple gain some ground in its battle with Samsung, which controls about three times Apple's market share in China. Apple's stock is up 1.5% in premarket trading.

Next, Costco said this morning that U.S. comparable-store sales were up only 2% in November, which included the critical Black Friday shopping weekend. While that's likely a better result than many of its rivals will see, it's still a big slowdown from the roughly 4% pace that Costco has been logging. Store expansions helped push overall sales higher by 5% to hit $8.78 billion in the month, though. And investors can expect more growth along those lines: The company has aggressive expansion plans for 2014 that should lay the foundation for continued sales increases. Costco's stock is down 1.8% in premarket trading.

Finally, Dollar General this morning reported third-quarter earnings that rose by 19% from the year-ago period. Total sales jumped 10.5% higher, as the retailer benefited from heavier traffic and a higher average transaction. Comparable-store sales were up a healthy 4.4% in the quarter. Dollar General's biggest sales gains continued to come from its consumables business, which also pushed profitability down slightly: gross margin fell by about half a percentage point, to 30.3%. The company expects to open 700 new stores next year, compared to the 650 it will open in 2013. The stock is up 2% in premarket trading.