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 sharply lower start to the stock market today, as the Dow Jones Industrial Average (DJINDICES:^DJI) lost 104 points, or 0.7%, in premarket trading this morning. Once again, global indexes seem poised to set the tone for trading in the U.S., as European markets fell by nearly 2% overnight after a worse than expected inflation reading out of the eurzone. Meanwhile, news is breaking this morning on several stocks that could see heavy trading in today's session, including Mattel (NASDAQ:MAT), National Oilwell Varco (NYSE:NOV), and Newell Rubbermaid (NASDAQ:NWL).

Mattel today posted surprisingly weak fourth-quarter earnings results. Sales shrunk by 6%, to $2.11 billion, and adjusted earnings slipped by 4% to $1.07 a share. Analysts expected $2.37 billion in revenue and $1.20 of per-share profit. The toy maker stumbled in the U.S. market over the holiday quarter, as overall revenue fell by 10%, including a 13% dip in Barbie sales, an 8% fall for Hot Wheels, and a 13% drop in its Fisher-Price brand. Mattel's balance sheet strength allowed it to boost its dividend by 6%, but investors seem more concerned about how the company can get its sales growth back on track. The stock is down 10.5% in premarket trading.

National Oilwell Varco said this morning that fourth-quarter earnings were $1.53 a share, or 2% lower than last year's haul. Revenue rose by 9% for the oil and gas equipment maker, to cap what CEO Pete Miller called a "challenging, but solid year." Both the top and bottom-line results were about even with what Wall Street expected. The company ended the year with a record $16 billion backlog for rig technology equipment, which is a good sign for future sales growth. And NOV is looking forward to the spinoff of its distribution business later this year, which should give it some added operational flexibility. The stock is up 2.2% in premarket trading.

Finally, Newell Rubbermaid this morning announced that sales grew by 2.9% in the fourth quarter, to $1.49 billion. Earnings came in at $0.47 a share, or 9% higher than the prior-year period. The consumer and commercial products maker saw growth across its business lines in the quarter, particularly in Latin American, which helped core sales rise at their fastest pace in years. Rubbermaid also provided guidance for 2014, saying that sales should improve by 3%-4%, and that profit should rise to $1.97 a share, or a bit below Wall Street's $2 estimate. The stock is up 0.76% in premarket trading.