The stock market resumed its upward surge on Thursday, climbing after yesterday's slight pullback. The Dow was up by triple digits, while other major benchmarks posted gains of nearly 1% to climb toward record heights yet again. Earnings season is beginning, and the early news has been good, with a number of companies pre-announcing better results than investors had expected to see. Broad-based macroeconomic factors are also working in the market's favor. Delta Air Lines (DAL -0.58%), Community Health Systems (CYH 2.88%), and First Solar (FSLR 0.43%) were among the best performers on the day. Below, we'll look more closely at these stocks to tell you why they did so well.

Delta takes to the skies

Shares of Delta Air Lines gained 5% after the commercial airline giant reported its fiscal fourth-quarter results. Revenue and adjusted net income were both up strongly, although the bottom-line gains were due to a one-time charge in the year-ago quarter related to pilot labor costs. Even though the company's internal expenses will likely keep rising, that didn't stop Delta from boosting its earnings guidance for the coming fiscal year, relying largely on the gains from lower corporate tax rates stemming from the recent tax reform effort in Washington. Competition in the industry is fierce, but Delta is still leading the way higher for the entire group.

Left side of a Delta airliner on a hangar floor under a cloudy sky near dusk.

Image source: Delta Air Lines.

Community Health gets a vote of confidence

Community Health Systems stock soared nearly 24% in the wake of a larger financial commitment from a major shareholder. A regulatory filing revealed that the hospital operator's largest shareholder, Chinese investment company Shanda Group, now owns almost a quarter of Community Health's outstanding shares. Despite the size of today's gains, the upward move does little to offset the nearly 90% drop in the stock over the past three years, and Community Health still faces an uphill battle to get its balance sheet into better condition and find ways to navigate an ever-changing industry environment in healthcare.

First Solar lights up

Finally, shares of First Solar jumped 9.5%. The solar manufacturer got a positive recommendation from analysts at Vertical Group, which started their coverage of First Solar with a buy rating. The solar giant's stock more than doubled in 2017, rising in light of strong demand for its large-scale solar generation projects. Expectations that First Solar's products won't be subject to tariffs that many of its competitors will have to pay also helped boost optimism about the stock. The company has ambitious growth plans through the end of the decade, but with a big increase in interest in renewable energy, First Solar seems to have the wind at its back and clear skies ahead.