Wall Street had a relatively uneventful day on Thursday, as market participants were content to watch the continuing string of earnings releases from some of the world's biggest corporations. Most major benchmarks finished close to flat on the day, although the tech-heavy Nasdaq Composite underperformed most of its peers, posting nearly a half-percent loss. Contributing to the Nasdaq's decline was a poor showing from Apple (AAPL -0.57%), but tech stocks weren't the only losers. United Continental Holdings (UAL 5.50%) and Unilever (UL 0.34%) (UN) were also among the worst performers on the day. Below, we'll look more closely at these stocks to tell you why they did so poorly.

Apple deals with iPhone 8 uncertainty

Shares of Apple sagged almost 2.5%, making it the worst-performing stock among the Dow Jones Industrials as investors expressed concerns about how the recent release of the iPhone 8 is going. Reports have suggested that demand for the newly available iPhone 8 has been weaker than many had hoped, and the news only makes it harder to predict how shoppers will react as the higher-end iPhone X is set to become available in the coming months. Also pulling Apple down were reports that state-owned Chinese wireless carriers have cut off LTE access for owners of the latest version of the Apple Watch. Investors will have to wait until Nov. 2 to find out how these factors have affected Apple's business.

Apple retail store location at Ala Moana.

Image source: Apple.

United flies lower

United Continental Holdings stock dropped 12% after the airline released its third-quarter financial results. The airline saw earnings fall almost 30% from the year-ago period, although even that sluggish performance was better than most investors had expected United to achieve. A nearly 4% decline in passenger revenue per available seat mile pointed to ongoing concerns that United hasn't been able to match its industry peers in terms of internal efficiency. Some will point to hurricane-related cancellations and rising fuel prices as headwinds for United, but other airlines did a better job of standing up to the same levels of adversity, and United needs to find a way to improve its business if it wants to match up to its rivals.

Unilever takes a hurricane hit

Finally, shares of Unilever finished down 6%. The consumer goods giant behind brand names like Ben & Jerry's and Dove soap posted quarterly results that reflected tough conditions in the retail market, as organic sales growth of 2.6% slowed from previous quarters. Strong performance in China and India helped lift the Asia region's numbers, and Latin America also showed solid growth. Yet negative factors like the hurricanes that hit Texas, Florida, Puerto Rico, and other areas near the Caribbean and Gulf of Mexico weighed on Unilever's Western Hemisphere results. Unilever has worked hard to cut costs, but the U.S. market will have to contribute more in the near future in order for the consumer giant to rebound fully.