Alcoa's many products saw mixed performance in its most recent quarter. Image: Alcoa.

Investors have waited well into January to see any signs of light at the end of the tunnel for a slumping stock market, but Tuesday finally brought some relief to beaten-down shareholders of U.S. companies. Even though energy markets continued to struggle, strength in other sectors of the market helped lift major-market benchmarks to their best gains of the New Year. Yet today's bounce wasn't enough to lift every stock, and Alcoa (AA), Penn National Gaming (PENN -0.74%), and Eldorado Gold (EGO -0.40%) were among the casualties in Tuesday's market session.

Alcoa dropped 9% in what many fear could be a harbinger of tough times ahead as fourth-quarter earnings season began. The maker of aluminum and other lightweight metals reported mixed results for the quarter, with its Value-Add businesses reporting strong performance despite ongoing weakness in prices for raw alumina and primary metals in the Upstream segment. Although the stock didn't immediately post a big drop following its earnings announcement after the market close on Monday afternoon, Alcoa investors seemed to come to the conclusion during Tuesday's session that even though the company has done its best to restructure itself in the best way possible, its ability to grow in a challenging global macroeconomic environment remains constrained. As long as tough conditions persist in key areas like construction, it'll be hard even for strength in aerospace and automotive to overcome the headwinds facing Alcoa right now.

Penn National Gaming lost 7% after getting a downgrade from analysts at Merrill Lynch. The analyst firm cut its price target to $17 per share, reflecting some of the same concerns that others have had regarding the interior U.S. gaming industry. Although Penn National and other domestically focused casino resort companies have fared much better than their global counterparts recently because of the big hit in the Asian gaming capital of Macau, signs of a potential end to economic expansion in the U.S. market could threaten a reversal of Penn National's success. As competing casinos in some of the same markets that Penn National serves suffer setbacks of their own, investors believe that the fate of the entire industry could be linked. Investors will have to watch not only Penn National's business but also those of its closest rivals as well in order to assess the overall health of the industry and its prospects for the rest of 2016.

Finally, Eldorado Gold plunged 19%. The company said late Monday that it would make significant changes to its investment plans in Greece, reflecting some of the challenges that it is facing in a time of upheaval for the small European nation. Eldorado said that its Hellas Gold subsidiary had received approval for an environmental impact study back in 2011, yet the Ministry of Energy and Environment in Greece still has not moved forward with permitting and licensing. Facing delays in court battles, Eldorado has chosen to suspend work at its Skouries project and set timelines for potential closures at its Olympias project. Prospects at other mines remain uncertain pending further review, but the political issues come at a terrible time for Eldorado given the poor gold market.