What happened

Shares of electric-truck start-up Nikola (NASDAQ:NKLA) were trading lower on Tuesday, after the company notified regulators that a whole lot of stock held by insiders could hit the market before long. 

Nikola's stock price was volatile all morning, moving up and down as buyers periodically stepped in to offset some of the selling pressure. As of 11:15 a.m. EDT, it was trading down about 4.1% from Monday's closing price. 

So what

In a regulatory filing after the U.S. markets closed on Monday, Nikola outlined the stock and warrants held by various insiders and warned investors that those shares will eventually hit the market.

Auto investors will recall (because it was just a few weeks ago) that Nikola was created by the reverse merger of privately held truck maker Nikola Motor with a special-purpose acquisition company called VectoIQ Acquisition, which was public. The merged company was named "Nikola Corporation" and VectoIQ's publicly traded stock and warrants were renamed accordingly.

A Nikola Tre, an electric heavy truck.

Nikola plans to begin shipping its electric tractor-trailer trucks late next year. Image source: Nikola Corporation.

Nikola is now notifying investors that warrants that were issued to investors and insiders when VectoIQ first went public will result in the insurance of up to 23.89 million shares of Nikola common stock when they're exercised. Nikola will receive $11.50 per share when those warrants are exercised. 

Given that Nikola has about 361 million shares outstanding, the additional stock coming to market as the warrants are exercised will result in a significant dilution (about 6.2%). It's not surprising that some investors chose to sell on that news.

Now what

Nikola also disclosed that a group of early investors -- including BlackRock and several Fidelity mutual funds -- now have the right to sell a total of 53.39 million shares. Nikola itself won't get any cash from those sales, but they'll increase the total number of shares available to other investors -- and if a lot of them are sold in the near future, it'll suggest that early investors aren't bullish on the stock. Stay tuned.