Nah, the "everything is securities fraud" trope is qbout some (usually immoral) behavior that a shareholder argues would materially affect the stock price, and which was not disclosed to shareholders.

Elon Musk announcing some M&A news with the intent of effecting price changes in TWTR,TSLA securies would be pretty boring, vanilla securities fraud.

That depends on the amount especially since he's already been caught doing this when he claimed he would take Tesla private

I knew it had to be Matt Levine :)