What happened

It's the start to the last trading week in June, and the bears have the pedal to the metal regarding shares of Nikola (NKLA 7.23%). The S&P 500 and Dow Jones Industrial Average are both inching lower, but Nikola's stock is racing downward. As of 10:54 a.m. ET, shares of the electric truck maker have fallen 16.3%.

While overall pessimism in the markets is likely motivating some to click the sell button, the major catalyst for the stock's fall today can be traced back to Friday, when the company reported a fire at its corporate headquarters.

So what

On Friday morning, Nikola tweeted news of a fire at its corporate headquarters in Phoenix, Arizona.

Since informing the public about the fire, Nikola hasn't provided any additional information, including insight into the extent of the damage, whether there's a suspect in the incident, or if other suspicious activity has occurred.

When companies don't provide news, doubt and fear can run rampant in investors' minds, leading them to exit -- or trim -- their positions. This seems to be the case today as the weekend came and went without an update from the company.

Now what

For those who have parked Nikola's stock in their portfolios, today's sell-off can be disconcerting. It's important for those who are optimistic about the company's prospects to recognize that nothing has happened that has changed the bull case for the electric vehicle stock. Therefore, they should continue to sit tight and await an update from management.