Chevron is worth 180B. If the millionaires banded together to control 50.1% of Chevron, they could oust the board, permanently destroy all of its oil production and distribution capabilities, and convert its oil fields into a permanently undrillable status.
Then, they could sell off the remaining assets (except the mineral rights), and only lose most of their money. Heck, the resulting shuttered corporation would probably be eligible for carbon credits.
Even better, instead of buying the oil reserves, they could buy out the corporations that own patents and factories for things like fracking equipment and critical car components.
Anti-trust would probably get in the way, but the global airbag industry has revenue in the single-digit billions. A band of 100,000 millionaires could easily acquire them all and charge $80,000 extra (per car) for bags headed to gas powered vehicles.