Since President Donald Trump's inauguration, the S&P 500 and Dow Jones Industrial Average have experienced declines of approximately 8%, marking the worst start to a year for the stock market in 50 years. This downturn has impacted the net worth of several billionaires, with Elon Musk's wealth falling by about 25%, equivalent to roughly $113 billion. Other notable billionaires, including Warren Buffett, have also seen changes in their financial standings during Trump's first 100 days in office. Forbes and other financial publications have highlighted the biggest billionaire winners and losers in this period, noting that hundreds of billionaires have become poorer since Trump assumed office.