Although we don't believe in timing the market or panicking over daily movements, we do like to keep an eye on market changes -- just in case they're material to our investing thesis.

The stock market closed the last full trading week of 2013 on a positive note, with the Nasdaq Composite climbing more than 1% and other major market benchmarks posting smaller but still sizable gains. For TIBCO Software (UNKNOWN:TIBX.DL), CarMax (NYSE:KMX), and InterDigital (NASDAQ:IDCC), however, there was a distinct lack of holiday cheer, with all three posting substantial declines even with the broader market rising.

TIBCO Software fell 10%, as the enterprise technology-infrastructure company's guidance disappointed shareholders. Results for TIBCO's November quarter were solid, with sales rising 6% and earnings coming in above the consensus among analysts. But expectations for slower growth in revenue and net income in the current quarter than investors had projected sent the stock lower, despite CEO Vivek Ranadive's assertion that the drop made it "the biggest buying opportunity for the stock in recent memory." Even with strong business prospects, TIBCO investors wanted proof before they'd take Ranadive's word about the stock's long-term potential.

CarMax dropped 9% after its quarterly report this morning left investors wanting more. Although sales rose a better-than-expected 13%, the car seller failed to provide the bottom-line growth investors had hoped to see. Of more concern was the fact that CarMax reported that the lenders that work with the company to arrange financing for its customers had started to get stricter about who could qualify for loans. With much of CarMax's growth in recent years hinging on buyers who need credit but lack a high-quality credit history, the company's move to look into offering direct subprime auto loans itself through its financing arm signals the importance of that part of the market. Yet it also introduces greater credit risk for the company.

InterDigital declined 10% after the provider of wireless technologies for mobile devices lost its patent case before the U.S. International Trade Commission against rivals Nokia (NYSE:NOK) and Huawei. InterDigital had alleged that the companies had improperly used technology related to features including data transmission and power management, but Nokia and Huawei prevailed in their contention that they hadn't infringed on patents and that some of the patents were in fact invalid. InterDigital has another case pending before the ITC, but investors are clearly skeptical that it can win in that dispute given yesterday's decision.