There is simply no other way, the only reason this is a big announcement is because Elon is very active on social media.
"We conduct investigations on a regular basis on a multitude of people over possible perceived wrongdoings."
-vs-
"We are conducting a thorough investigation on Musk, Tesla, SpaceX because we believe he did something wrong."
The first is a non-answer, and puts no blame anywhere. Its their reason to be, so its unsurprising. The second statement itself changes the market the very same way he was claimed to do, and paints him and the companies in a bad light, prior to any finding of fact.
I'm arguing for the defense and protection of the accused. By the very definition, they are not guilty/liable UNTIL the court says they are. But this style of bandying around "We're INVESTIGATING ____" Only puts strong implicit blame and guilt on the accused.
This reminds me of "perp watches" posed by police departments on Facebook and twitter. No charges, but arrested - and you get to live in the newspaper and social media regardless if you are exonerated. Cause, public shaming?
edit: s/peep/perp/