Don't expect TSLA share price volatility to go down for a long time.
And S&P500 inclusion won't make it better, it might make it worse!
Why?
I think people confound S&P500 inclusion as causing stability in companies' valuations, when in fact it's probably just correlated. Companies that join S&P aren't usually growing so fast, so by the time they make it, they are stably profitable, not growing too quickly, so everyone has a relatively clear framework for how to value them. The price doesn't go crazy.
Tesla doesn't follow that. Yes they are increasing profitability, so the downside risk is less, but the sheer growth potential is still huge and the massive amount of upside will still cause huge swings in stock price as perceptions change.
As for inclusion, I did this thought experiment that maybe y'all can poke holes in. Imagine funds had to buy 90% of the free float. Heck, say there was only a million shares available for trading. That means share price / valuation would be dependent of a handful of people and could have even bigger swings. No way that would reduce volatility!
So maybe Tesla stock will be even more volatile until it stops rapidly growing and disrupting trillion dollar markets.
When's that going to happen?