What happened

Easy come, easy go. After two straight days of gains, cruise line stocks were headed back down today.

Whether it's Carnival's (NYSE:CCL) 5.4% decline, Royal Caribbean's (NYSE:RCL) 5.2% slide, or Norwegian Cruise Line Holdings' (NYSE:NCLH) more modest 4% slump (all as of 1:05 p.m. EDT on Wednesday), every major publicly traded cruise line stock is sinking today.

3 red arrows going down and crashing through the floor

Image source: Getty Images.

So what

The pair of analyst price-target cuts that Royal Caribbean stock suffered on Tuesday is catching up to the cruisers today. In back-to-back reports, investment banks Stifel Nicolaus and then J.P. Morgan warned that cruise lines' return to operation may be more "gradual" than speedy this year (or next), and reduced their estimated value of Royal Caribbean stock accordingly. Royal Caribbean's announcement today that it has just sought another $700 million in term loans to tide it through the recession tends to confirm that theory.

While the analyst reports focused on Royal Caribbean, it's logical to believe that any restrictions on cruising that apply to that company would apply just as strictly to its rivals Carnival and Norwegian Cruise Line.

Now what

This conclusion was just as logical yesterday as it is today, so what delayed the reaction by 24 hours? Russian President Vladimir Putin announced on Tuesday that scientists in his country have registered a vaccine against COVID-19 that they are calling Sputnik V.

While long on hype and short on specifics, the news seems to have briefly encouraged investors in a variety of coronavirus-hit industries. Just the reminder of the potential that a coronavirus vaccine has to bring customers back to cruises was enough to lift cruise stocks yesterday, despite the cautionary analyst notes.

Today, things are looking a bit different. As skeptics arise to throw cold water on Russia's assertions, the cruise industry's recovery is looking as far away as ever. And that's why Carnival, Royal Caribbean, and Norwegian Cruise stocks just crashed.

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.