This 24 year old Korean trader made ₩300 million with borrowed money, then lost it all in four weeks.

Lee Seung-ho, a university student in Seoul, took a 500% margin loan and turned 20 million won in savings into 300 million, a 15x gain, Per Reuters.

Then Korean stocks started crashing violently, his brokerage forced liquidations, and his account fell below his original investment.

He says he plans to take out another margin loan once he saves up enough money again.

His story isn't unusual, it's the system working as designed.

Margin loan balances in Korea's stock market hit a record 38.63 trillion won on June 24.

Broader investor debt, including other forms of borrowing, crossed 60 trillion won by the end of May, right as Korea's $4.1 trillion market became the world's most volatile.

On Thursday, authorities banned new listings of leveraged ETFs tied to individual stocks, just two months after approving them.

The head of the Financial Supervisory Service has already admitted the approval was rushed.

Leverage accelerates losses on the way down far faster than it builds wealth on the way up, and right now, an entire generation of Korean retail traders is finding that out the hard way.