Wednesday was a mixed day on Wall Street, with major benchmarks largely treading water as the S&P 500 approached a record closing high. Market participants seem conflicted between the strong showing that the U.S. economy has had throughout 2018 and the potential political ramifications of ongoing investigations in Washington, which yesterday added the high-profile verdict against former Trump campaign manager Paul Manafort and the plea bargain of attorney Michael Cohen. Yet good news from several companies reminded investors of what's important at the individual stock level. Exact Sciences (EXAS 2.38%), Pure Storage (PSTG 2.12%), and Zynga (ZNGA) were among the best performers on the day. Here's why they did so well.

Exact Sciences gets exactly the right deal

Shares of Exact Sciences soared 31.5% after the colorectal cancer screening specialist announced a deal designed to boost promotion of its Cologuard test. According to a press release from Exact Sciences, Pfizer (PFE 1.00%) will work with the company to promote the non-invasive screening test, with Pfizer sales representatives reaching out to physicians and health systems. Pfizer will also work together with Exact Sciences on the marketing campaign for Cologuard. In exchange, Exact Sciences will pay Pfizer a promotion fee as well as royalties on revenue. With the deal running through the end of 2021, investors seem to think that Pfizer could help Exact Sciences dramatically increase sales of Cologuard in the next few years.

Cologuard test kit with collection bin and instructions.

Image source: Exact Sciences.

Pure Storage exceeds expectations

Pure Storage stock rose 14% after the data-storage specialist reported its financial results for the second quarter. The company said that it reversed a year-ago loss with a modest adjusted profit, defying expectations among those following the stock, and revenue climbed by more than a third. Pure Storage also raised its guidance for the remainder of the fiscal year, noting that between the acquisition of cloud-storage software provider StorReduce and strong fundamental growth prospects, it expects to have better sales and boost its gross margin figures as well. With more enterprise clients moving into the cloud, Pure Storage's solutions should remain in high demand.

Zynga gets a win

Finally, shares of Zynga picked up 8%. The video game maker said that it had made a partnership with Disney (DIS -0.55%) to produce a mobile-platform game based on the popular Star Wars franchise. In addition to assuming control of the existing Star Wars: Commander game, Zynga will have an option to produce an additional title. Some commentators worry about whether the Star Wars has the staying power that many had anticipated when Disney bought Lucasfilm. But for the much-smaller Zynga, any deal with Disney sets the stage for potential future agreements with the entertainment giant as well, and that's a relationship that the game maker will want to cultivate further.