The stock market performed reasonably well on Friday, sending major benchmarks to gains of 0.25% to 0.5% on the day. Favorable news from the U.S. economy outweighed any concerns about geopolitical events occurring this weekend, including the much-awaited final phase of the French elections. The Dow regained the 21,000 level, and the S&P 500 finished just below the 2,400 mark. But some stocks missed out on the rally, and Puma Biotechnology (PBYI 0.34%), Trex (TREX -7.15%), and National CineMedia (NCMI 0.92%) were among the worst performers on the day. Below, we'll look more closely at these stocks to tell you why they did so poorly.

Puma sees a key departure

Shares of Puma Biotechnology fell 16% after the biotech company said in an SEC filing that an executive in charge of regulatory affairs and project management would resign from the company effective May 15. The filing said that Dr. Robert Charnas had told Puma last week about his departure, with the filing citing health reasons for the move. Yet investors seem to be nervous about the timing, coming immediately before a key advisory panel meeting for its neratinib treatment for breast cancer. Given that neratinib has seen patients in trials report negative side effects, some investors believe that Puma might have trouble getting a positive recommendation from the panel when it meets later this month. The stock's decline might prove to be an overreaction, but the company's decision to put the information in a filing rather than doing a full press release might have contributed to investors' skepticism about the move.

Deck made of Trex materials.

Image source: Trex.

Trex falls despite solid growth

Trex stock declined 9% in the wake of the company releasing its first-quarter financial results. The home deck and railing specialist said that sales climbed 10% from year-ago figures, with increasing margins helping to produce an 18% rise in net income. Trex has gotten a lot of accolades from its industry, including kudos for its environmentally friendly practices and its leadership role in promoting alternatives to traditional wood decking and railing materials. Yet guidance for sales of $160 million in the second quarter only matched investor expectations, and despite calls for improving market share and margin figures, Trex investors seemed to want more from the decking specialist as the high spring season for home improvement begins.

National CineMedia plays a horror show

Finally, shares of National CineMedia lost more than a quarter of their value. The in-theater media company said that revenue was down 6% from the year-ago quarter, leading to a drop in operating income and a wider net loss compared to the first quarter of 2016. Despite gains in sales from its local and regional segment as well as its digital and beverage businesses, softness in national advertising revenue weighed on the company's overall results. CEO Andy England reiterated that he sees 2017 as "a transitional year for NCM as we evolve from being the largest cinema network into a truly progressive, integrated digital media company." That means investors have to expect tough results this year, and National CineMedia's guidance called for revenue to fall 1% to 6% and produce a 6% to 12% drop in adjusted operating income. As movie theaters struggle to get people to leave their homes for entertainment, National CineMedia will have to work harder to find new avenues for growth.