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.

What: Shares of Cooper Tire & Rubber Co. (CTB) were down 13% as of 12:10 p.m. Friday after the company announced weaker-than-expected first-quarter results.

So what: Quarterly net sales fell 16.7% year over year to $663.2 million, including a 6% increase in sales from the Americas to $599 million, and a 65.5% decrease internationally to $107 million. To be fair, the latter decline was primarily due to $185 million in absent revenue, before intercompany eliminations, following the sale its CCT joint venture this past December. Excluding CCT, international volume fell $7 million on difficult comps in Europe, as well as lower volume in China as tariffs decreased exports to the U.S., more than offsetting higher sales to the domestic Chinese market. 

Meanwhile, that translated to net income of $41 million, or $0.69 per share. Analysts, on average, were anticipating higher net income of $0.77 per share on sales of $682.6 million.

Now what: Cooper Tire didn't provide specific guidance in today's press release for the remainder of the year. But it did note that while raw materials costs will be down slightly on a sequential basis in Q2, they will "generally trend slightly higher" in the second half of 2015.

As such, Cooper Tire will use the seasonally weaker second quarter to build inventory ahead of its stronger third and fourth quarters. Cooper also anticipates continuing to meet or exceed industry unit volume growth in the United States. Internationally, operating profit will likely be breakeven on the sluggish European economy and oversupplies in China. Overall, Cooper anticipates delivering full-year 2015 operating margin of 8% to 10%.

All things considered, it's unsurprising the market is bidding shares of Cooper Tire down given both misses on Q1 earnings and revenue, as well as cautious guidance going forward. While that doesn't mean the company can't improve and ultimately deliver value for shareholders over the longer term, I'm content for now watching Cooper Tire's progress from the sidelines.