Total U.S. margin debt reached an all-time high of approximately $1.5 trillion in June, according to the Financial Industry Regulatory Authority (FINRA). This surge is significantly driven by retail investors increasing their leverage. Robinhood's margin book grew to a record $21.6 billion in the second quarter, marking a 127% year-over-year increase and a 332% jump from Q2 2024's $5 billion. Analysts attribute the rise to the ongoing bull market, fear of missing out (FOMO), and easier access to margin investing via smartphone apps, alongside brokers offering low margin rates. Experts caution that while the market may appear healthy, increased margin debt injects fragility into the system, amplifying potential losses.