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.

For the second day in a row, stocks didn't deliver the results that bullish investors had hoped to see. Despite modest gains for the Dow, the broader S&P 500, and the tech-heavy Nasdaq Composite, both posted declines on the day. Yet, even with the gloomy mood, many stocks celebrated with substantial gains, including Rite Aid (NYSE:RAD), Portugal Telecom (NYSE: PT), and YY (NASDAQ:YY).

Rite Aid soared almost 9%. The drugstore chain reported same-store sales growth in December of 2.9%, continuing to accelerate its growth as it keeps trying to turn itself around amid substantial debt and competitive threats from larger drugstore rivals. Once again, though, pharmacy gains were much higher than the overall growth in sales. That suggests ongoing weakness in the front end of the stores, and many investors would like to see that improve before they get fully behind Rite Aid's stock.

Portugal Telecom picked up more than 9% on a good day for southern European telecom companies, with Telecom Italia (NYSE: TI) also posting solid gains of nearly 8%. Europe has slowly dragged itself out of recession, and investors have looked to the continent's markets as potential outperformers if the recovery continues. Portugal Telecom, Telecom Italia, and other peers across Europe largely suffered substantial losses during the eurozone's financial difficulties, and so it makes sense that they'd bounce back the strongest in times of improving conditions.

Chinese social-media company YY jumped 11% as investors get more bullish on the prospects for China. Throughout 2013, Chinese Internet stocks have performed well, with giant online-search company Baidu (NASDAQ:BIDU), and smaller players alike posting enviable total returns. As investors adjust their portfolios for the New Year, YY could see more volatility if the trend that helped send it up about 250% in 2013 starts to falter. For now, though, shareholders seem committed to the company and its future.

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.