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.

Investors can expect a positive start to the stock market today, as the Dow Jones Industrial Average (^DJI -0.17%) gained 40 points, or 0.3%, in premarket trading. The talk on Wall Street today will likely be dominated by the latest report from the Bureau of Labor Statistics, which this morning said the economy created 113,000 jobs in January, below 2013's average monthly job gain pace of 194,000. Economists were expecting a gain of closer to 190,000 jobs last month. The unemployment rate ticked lower to 6.6%, as expected.

Meanwhile, news is breaking this morning on several stocks that could see heavy trading in today's session, including Apple (AAPL 0.55%), Activision Blizzard (NASDAQ: ATVI), and Moody's (MCO -0.35%).

Apple shares are up 2% in premarket trading after The Wall Street Journal reported that the company spent $14 billion buying back its stock over the last two weeks. By comparison, Apple shelled out less than $8 billion on both share buybacks and dividends through the entire December quarter. In an interview with the newspaper, CEO Tim Cook said that Apple was "surprised" by the sell-off in shares after it reported its fiscal first-quarter results that included record quarterly revenue of $58 billion and record profit of $14.50 a share. Taking advantage of a stock valuation of less than 13 times last year's earnings, it's hard to argue with Apple's opportunistic move here.

Activision Blizzard shares are trading near an all-time high after the company last night posted strong fourth-quarter results. Sales came in at $2.3 billion, and profit was above forecasts at $0.79 a share. Activision's key Skylanders and Call of Duty franchises sold well during the holidays, and the company even saw a gain in subscribers for its aging World of Warcraft blockbuster. But investors should be more excited about the game publisher's record slate for 2014, which is packed with new intellectual property such as Destiny, as well as the latest installments in its biggest established franchises. Activision's stock is up 7.8% in premarket trading.

Finally, Moody's today posted a 3% increase in quarterly revenue, to $779 million. Earnings improved by 34% to $0.94 a share, as the financial giant was able to keep a lid on cost growth while sales improved in each line of its business. For the year ahead, Moody's said that despite "variable market conditions" it should deliver a solid sales boost in 2014; earnings should be between $3.90 and $4 a share, slightly ahead of analysts' estimates. The stock is up 3.2% in premarket trading.