Elon Reeve Musk (/ˈiːlɒn/ EE-lon; born June 28, 1971) is a businessman known for his key roles in Tesla, SpaceX, and Twitter (which he rebranded as X). Since 2025, he has been a senior advisor to United States president Donald Trump and the de facto head of the Department of Government Efficiency (DOGE). Musk is the wealthiest person in the world; as of March 2025, Forbes estimates his net worth to be $320 billion $BTC …