What happened 

Cruise ship stocks fell on Wednesday as the number of COVID-19 cases rose in multiple U.S. states and international markets. As of 2:55 p.m. EDT, shares of Norwegian Cruise Line Holdings (NASDAQ:NCLH), Carnival (NYSE:CCL), and Royal Caribbean (NYSE:RCL) were down 12%, 8%, and 8%, respectively. 

So what 

With most states moving to reopen their economies, it was a near certainty that more people would get sick from the novel coronavirus. However, reports of spiking COVID-19 case counts in states such as California, Arizona, and Texas could drive authorities to slow reopening plans, such as by extending no-sail orders for the major cruise ship operators.

Rough water off the side of a cruise ship.

Cruise ship investors might want to brace for rough seas. Image source: Getty Images.

Carnival, Royal Caribbean, and Norwegian Cruise Line have been forced to keep most of their ships docked since March, due to sailing restrictions imposed by the Centers for Disease Control (CDC) and other international authorities. Countries such as Canada, Spain, and Australia have extended their sailing bans on cruise ships in recent weeks, and it's possible that the CDC could follow suit.

Now what

Royal Caribbean, Carnival, and Norwegian Cruise Line have all raised large amounts of cash via debt offerings in recent months in order to be able to ride out coronavirus-related sailing restrictions. But there's a limit to how much cash they can raise by selling debt, and stock offerings would dilute shareholders.

Thus, if surging COVID-19 case counts lead to more no-sail order extensions -- or if people choose to forgo booking voyages once cruise ships are allowed to sail again -- Carnival, Royal Caribbean, and Norwegian Cruise Line could face rough waters ahead.