What happened

Shares of Lucid Group (LCID 0.41%) dropped by as much as 5% Thursday morning and remain lower by 4.1% as of 10:56 a.m. ET. The drop extends a decline in the shares of the luxury electric sedan maker by almost 20% over the last month. 

So what

It may be what the company hasn't said that is pushing investors to sell Lucid shares. This week, fellow EV start-up Rivian Automotive joined legacy automakers Ford and General Motors in agreeing to adopt Tesla's EV charging network. Those companies felt the need to partner with the EV leader and their largest competitor in order to grow a customer base for their EV offerings. 

Tesla's Supercharger network of fast chargers is the clear leader in the U.S. and Canada and access could ease range anxiety for potential customers of Tesla's competitors. That could go a long way in helping sales. But Lucid hasn't said it will support Tesla's North American Charging Standard (NACS) format, and there is reason to believe it never will. That could be a major disadvantage for Lucid over the long term. 

Now what

Lucid's CEO and chief technology officer, Peter Rawlinson, was formerly a lead design engineer at Tesla, and his relationship with Elon Musk has been contentious in the past. It may not be surprising that the leaders of two competing companies are critical of each other, but Twitter exchanges between the two in the past have gotten more personal.

Musk predicted at one point that Lucid was on the path to bankruptcy. The competing CEOs even argued about what Rawlinson's actual role had been in designing Tesla's flagship Model S. 

Investors may be wondering if Rawlinson will be able to overcome that personal dispute and agree to partner with Tesla for use of its charging network. If NACS becomes the standard among most EV makers, and Lucid owners don't have access to it, it could affect demand. 

While no investor knows what is going on behind the scenes, it's clear that NACS is making progress in becoming more widely available to other manufacturers. And the contentious relationship between Musk and Rawlinson has played out in the public eye. It seems investors don't want to wait until it's too late to discover Lucid isn't joining the charging network.