Musk said he wants to form the America Party. A third party has never won the presidency, but they have influenced elections, experts say — mostly as spoilers.

Tesla stock lost nearly 7% Monday after Elon Musk announced plans of launching the “America Party.” William Blair downgraded TSLA shares.

Elon Musk's net worth has taken a $15.3 billion hit after the Tesla CEO announced he was to form a new political party. The news sent ripples through financial markets and spooked investors concerned about Musk's political ambitions and possible implications for Tesla's brand and business operations.