The U.S. Securities and Exchange Commission (SEC) has significantly influenced the 2025 cryptocurrency market through its enforcement actions and policy changes. Under Gary Gensler, the SEC secured a $46 million judgment against MCC International for fraudulent schemes, impacting market integrity. A study revealed SEC rulings on crypto securities led to a 12% average return drop, with smaller assets experiencing over 20% volatility spikes. In a notable case, the SEC classified LUNA and UST as investment contracts, resulting in a $4.5 billion fine and an 18% drop in Bitcoin prices. The SEC's shift towards structured rulemaking under Paul Atkins, including revoking Staff Accounting Bulletin 121, is expected to enhance institutional crypto custody, coinciding with a drop in Bitcoin's 30-day volatility index from 85 to 52. Despite these changes, regulatory ambiguity persists, particularly in the SEC's ongoing appeal in the Ripple Labs case and its interpretations of stablecoins and meme coins.