Wall Street had another solid day on Friday, and major benchmarks climbed to record highs. Signs of stability for the U.S. led market participants to hope that growth would remain strong enough to keep company fundamentals healthy while being weak enough to deter the Federal Reserve from making further interest rate increases in the near future. Nevertheless, concerns about North Korea and the potential for another hurricane to hit the U.S. mainland as early as next week kept gains in check. Moreover, some companies had bad news that prevented them from participating in the rally, and Carnival (CCL 0.25%), Immunomedics (IMMU), and Fitbit (FIT) were among the worst performers on the day. Below, we'll look more closely at these stocks to tell you why they did so poorly.

Carnival deals with stormy seas

Shares of Carnival dropped 4% as investors tried to assess the potential impact of Hurricanes Harvey and Irma on the cruise ship operator's long-term business. On one hand, some analysts believe that the combination of catastrophic weather events and geopolitical tensions could lead customers to avoid the high seas. Yet such calls aren't new to the industry, and Carnival and its peers have historically been able to overcome such concerns through a combination of attractive pricing and unparalleled amenities. Even if Carnival suffers a short-term hit from the two recent hurricanes, it's still in good position to take advantage of demographic trends favoring the industry even as cruise operators ramp up capacity.

Cruise ship with person zip-lining in foreground.

Image source: Carnival.

Immunomedics does some restructuring

Immunomedics stock finished down 5% after the biotechnology company announced a deal to restructure some of its existing debt. The antibody developer said that it had entered into agreements with certain holders of convertible debt due in 2020 under which they will exchange the debt they own for common stock of Immunomedics. In exchange for debt with $80 million in face value, investors will receive 14.1 million shares of stock plus a potential larger number based on the price of the stock over the next three trading sessions. The move will reduce Immunomedics' debt, but it will also dilute existing shareholders, and that's likely the reason for the decline today.

Fitbit deals with competition

Finally, shares of Fitbit declined 4%. The maker of fitness-tracking wearable devices has been under pressure throughout much of the year due to competition from other device manufacturers, and the recent announcements from the world's largest company about its own wearable device offerings have investors a bit more nervous about Fitbit's ability to keep up. Nevertheless, those who are bullish on Fitbit think that its combination of more attractive price points and greater battery life should be able to help it sustain its niche market. Investors will have to wait and see how the key holiday season goes for Fitbit and its rivals, but this year will be critical for Fitbit's long-term prospects.