The stock market gave up ground on Tuesday as market participants processed the news that National Security Advisor John Bolton had been fired, and dealt with the rotation away from momentum stocks toward more value-priced issues. In addition, some bad news for well-known individual companies had a negative impact on market sentiment. Starbucks (NASDAQ:SBUX), Roku (NASDAQ:ROKU), and Universal Display (NASDAQ:OLED) were among the day's worst performers. Here's why those stocks did so poorly.

Starbucks deals with an accounting issue

Shares  of Starbucks were down almost 5% after reports that the U.S. Securities and Exchange Commission has made inquiries about the coffee giant. In particular, The Wall Street Journal reported that the SEC wants Starbucks to explain exactly how the company's accounting practices measure incoming revenue. However, more than 200 companies have gotten similar inquiries about the revenue recognition practices over the past couple of years, and Starbucks doesn't believe that there will be any further exchange of information necessary between it and the SEC on the matter. With some investors fretting about earnings growth, Starbucks can't afford to let a controversy derail its long-term strategy.

Starbucks mermaid logo on circular sign hanging from ceiling.

Image source: Starbucks.

Roku faces competition

Roku's shares fell 11% as the streaming video company faced a new competitive threat. In Tuesday's autumn product release event, Apple (NASDAQ:AAPL) said that it intends to make its Apple TV+ video service available as of Nov. 1, with a subscription price of $4.99 a month. That's quite a bit less than most industry watchers had been expecting, and it will put pressure on other video content providers as they attempt to maintain their market shares and margins in an increasingly competitive market. Yet those who are bullish on Roku note that it could be a winner no matter which companies win the content wars; as long as people want video services, Roku will have a base of customers from which to generate sales and profits.

Universal Display takes a hit

Finally, shares of Universal Display were down more than 20%. The maker of organic light-emitting diode display technology was one of many tech stocks that fell more sharply than the overall market on Tuesday, but Universal's drop also likely stemmed from concerns about CEO Steve Abramson selling almost $7 million in stock late last week. Investors were also speculating about what role Universal Display's products will play in Apple's latest product releases. With big-name tech stocks in flux, investors will just have to wait and see whether the OLED display specialist can sustain its growth and produce the results that shareholders expect.