Which trader lost the most money?

The Costliest Trades in Financial History

When it comes to colossal losses on Wall Street, few names stand out like Bill Hwang. In 2021, the former hedge fund manager behind Archegos Capital Management made headlines for losing nearly $10 billion in a matter of days. His downfall was swift and dramatic, triggered by a sudden collapse in stocks heavily leveraged through total return swaps—complex derivatives that amplified both his gains and, ultimately, his losses.

Hwang’s case was particularly striking not just for the sheer scale of the loss, but for how quietly it unfolded before exploding into public view. Unlike traditional traders who buy and sell shares outright, Hwang used swaps to gain massive exposure without directly owning the underlying stocks. When those positions started to unravel amid market volatility, banks scrambled to offload billions in holdings, sending shockwaves through the financial world.

Still, Hwang wasn’t the first to see a trading empire crumble overnight. In 2012, Bruno Iksil, dubbed the "London Whale," incurred massive losses while trading credit default swaps (CDSs) at JPMorgan Chase. His positions in the derivatives market led to over $6 billion in losses, drawing intense regulatory scrutiny and becoming a symbol of unchecked risk-taking.

Both cases underscore a recurring theme on Wall Street: the double-edged sword of leverage. While instruments like total return swaps and CDSs can boost returns, they can also magnify risks beyond expectations—especially when markets turn. Hwang’s collapse, centered in part from his base in Boonton, New Jersey, serves as a stark reminder that even the most sophisticated strategies can fail under pressure.

These episodes live on not just in regulatory reports, but in the cautionary tales whispered across trading floors—where fortunes can vanish as quickly as they’re made.