The stock market fell on Tuesday, giving up early gains as investors tried to work through the potential ramifications of the latest shake-up in the Trump administration. Major benchmarks initially rose early in the day after Donald Trump announced that he would replace Secretary of State Rex Tillerson with Mike Pompeo, the current director of the Central Intelligence Agency. Also potentially hurting sentiment on Wall Street was negative news dogging several individual companies. U.S. Steel (NYSE:X), National CineMedia (NASDAQ:NCMI), and Myriad Genetics (NASDAQ:MYGN) were among the worst performers on the day. Here's why they did so poorly.

Investors ignore U.S. Steel's update

Shares of U.S. Steel nearly 8% after the steelmaker gave new guidance in light of the recently imposed tariffs on imported steel. The company now thinks that its full-year pre-tax operating earnings will be about $1.7 billion for the full year, due largely to shipments of an additional 100,000 tons from a newly reopened plant once it's fully operational. Yet analysts weighed in with more pessimistic assessments, saying that any positive impact on the company's results was already reflected in the stock price. With the potential that tariffs could get undone at some point, banking too much on U.S. Steel's new forecast could be dangerous in the long run.

Flat steel sheets coming out of heating oven.

Image source: U.S. Steel.

National CineMedia gets left in the dark

National CineMedia stock dropped 8% in the wake of the company's fiscal fourth-quarter financial report. The movie advertising specialist said that revenue fell 1% from the year-earlier period, and it posted a net loss due to the impact of tax reform and costs related to a transition in its chief executive officer position. New CEO Andy England admitted that "2017 was a challenging year for NCM," but he and the company remain encouraged by what they saw as improving performance in the second half of the year. With projections including flat to 4.5% revenue growth, investors in National CineMedia aren't confident that the theater ad company will see dramatic improvement in the near future.

Subpoena hits Myriad

Finally, shares of Myriad Genetics fell 12%. The genetic testing specialist got a subpoena from the federal government's overseer of the Medicare and Medicaid programs, requesting further information with respect to an investigation about possible improper reimbursement claims submitted to the agency. Analysts at Piper Jaffrey speculated that the investigation would center either on inappropriate testing or improper billing practices, but regardless, the stock would likely remain stuck near current levels until the matter gets resolved. With many having concluded that Myriad's best days are behind it, the latest news adds another reason to reconsider holding shares.

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