The stock market once again recovered from early losses on Thursday to finish the day with modest gains. The Dow gained nearly 50 points, and broader market benchmarks posted increases of roughly 0.25% to 0.5%. Investors are still somewhat on edge as they wait to find out which direction the Federal Reserve will go in setting the course of future interest rates at its mid-June Federal Open Market Committee meeting. The unprecedented period of low interest rates has been a major contributor to stock market strength, because alternative investments like bonds and bank certificates of deposit haven't been terribly attractive with their rock-bottom returns.

Even though the stock market did well today, some individual stocks weren't so lucky, and among the worst performers were Sarepta Therapeutics (NASDAQ:SRPT), Signet Jewelers (NYSE:SIG), and DeVry Education Group (NYSE:ATGE).

Sarepta Therapeutics plunged 27% after the Food and Drug Administration released information that could threaten the company's ability to maximize profits if its treatment for Duchenne muscular dystrophy eventually receives FDA approval. The FDA's recommendations centered on its compassionate use policy, saying companies generally could only get paid to offset its direct costs in making drugs available to patients on treatments that haven't yet been approved. Sarepta shareholders seemed to take the guidance as specifically meant for the company, even though it will apply equally to all companies and treatments still in the developmental stage. The effect of the guidance makes it even more important for Sarepta to get FDA approval for its eteplirsen drug, but its prospects are extremely uncertain.

Image source: Signet Jewelers.

Signet Jewelers fell 7% in the wake of negative comments from a well-regarded investment letter. Signet is the company behind the Jared, Zales, and Kay jewelry chains, and reports indicate that possible troubles include customer complaints about diamond quality as well as the magnitude of the jewelry company's financing division. The comments about Signet's credit exposure mirrored what many companies experienced during the run-up to the financial crisis, and some believe Signet's success now relies as much or more on whether its customers will repay loans as on its outright sales prowess.

Finally, DeVry dropped 13%. The for-profit education company suffered its second major executive defection in just over a week, with CFO Tim Wiggins saying late Wednesday that he would leave. The move follows closely after CEO Daniel Hamburger said he would pursue other opportunities, and investors are more nervous than ever that insiders are aware of further challenges to DeVry's business that could motivate their decisions to depart. With a lawsuit from the Federal Trade Commission outstanding and the possibility of new guidelines from the Department of Education that could put further pressure on for-profit education, DeVry's risk level just got a lot higher.

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