Alex Wong/Getty ImagesThe 2024 stock market boom fueled a surge in net worth gains for America's richest.Elon Musk's wealth increased by $213 billion, driven by Tesla's stock rise after the election.Other big gains came from Mark Zuckerberg of Meta and Jensen Huang of Nvidia.The stock market boom in 2024 made the rich even richer, with US billionaires dominating Bloomberg's Billionaire Index.According to the index as of December 30, just 11 American billionaires and one billionaire family gained nearly $1 trillion in wealth.