Wall Street finished the week on a down note, with major benchmarks losing ground on Friday. Following a period of optimism that took markets close to new highs, the trade-tension pendulum seemed to swing back toward the more contentious side today after Chinese officials called off a trade delegation meeting with U.S. agricultural industry representatives. In addition, concerns in specific industries hurt overall sentiment. Netflix (NFLX 1.74%), Roku (ROKU 1.00%), and PG&E (PCG 0.43%) were among the worst performers. Here's why they did so poorly.

Netflix and Roku reveal tension in streaming

Both Netflix and Roku saw their stock prices drop today, with Netflix shares falling 5.5% and Roku's plunging a steeper 19%. Increased competition in the video-streaming industry has contributed to declines for both stocks, as new moves from players like cable giant Comcast showed that current leaders will have to fight to keep their positions in the space.

Symbol of television with Netflix Recommended TV text on it.

Image source: Netflix.

Netflix CEO Reed Hastings specifically pointed to upcoming launches from Disney and Apple later this year, as well as Comcast's NBC Universal next year, acknowledging that the streaming industry is in a state of flux. Recent bidding for legacy television and other content has soared, reflecting just how much demand there is for up-and-coming streaming players to lock in audiences with attractive shows.

For Roku, stock analysts were the primary culprit. Pivotal Research Group believes that Roku's share price could fall 50%, putting a sell rating on the stock and setting a $60 price target. The big question is whether Roku can continue to count on its partnerships with television manufacturers to integrate the Roku TV platform into their sets, even as competitors aim to woo audiences through other means. Going forward, both Roku and Netflix will have to work hard to make the most of their existing customer bases while attracting new viewers with platform features and content.

PG&E faces a rival plan

Finally, shares of PG&E lost 5%. The bankrupt utility had to deal with a new threat, as bondholders and victims of California wildfires gathered together as a creditor committee to propose a competing bankruptcy reorganization plan to the court. PG&E has maintained that its own plan should gain approval, but creditors want provisions that would bring more compensation to fire victims even if it means shareholders getting little or nothing after the utility emerges from bankruptcy protection. A court hearing is expected in early October, and shareholders will have to watch closely to see which way the bankruptcy court goes with the measure.