Volatility drag is what eats away at a leveraged position even when a margin call never comes.
By mid-June, margin loan balances on South Korea’s KOSPI had hit a record 38.6 trillion won. A month later they had collapsed to roughly 27.4 trillion won — not because investors calmly took profits, but because forced liquidations tore through the market. In the first ten days of July alone, more than 1.2 million leveraged accounts hit margin-call thresholds and roughly 360,000 were wiped out by their brokers, even in blue-chip names like Samsung Electronics and SK Hynix. In an earlier post, we covered forced deleveraging — the moment a lender demands more collateral than a fund can post, and the position gets sold on the lender’s timeline, not the investor’s. This is the sequel: the version of leverage decay that doesn’t need a lender to show up at all.
Here’s the math. Say a stock goes up 10%, then falls 10% the next day. It sounds like a wash, but it isn’t: 100 becomes 110, then 110 loses 10% and becomes 99. You’re down 1% even though the two moves canceled out on paper. Now double the leverage: the fund needs to be up 20% and down 20% to track those same daily moves. 100 becomes 120, then 120 loses 20% and lands at 96 — a 4% loss on a round trip that, unleveraged, would have cost you just 1%. The more a price zigzags rather than trends, the more leverage quietly erodes the account — no lender, no phone call, just arithmetic.
The other side of this math is recovery. A 50% loss needs a 100% gain just to get back to even — a brutal asymmetry on its own. Add 2x leverage, and the market only needs to drop 25% to inflict that 50% loss on your equity. That’s the trap that caught so many Korean retail investors this summer: they weren’t wrong that Samsung and SK Hynix were solid companies. They just didn’t have room to survive the zigzag on the way to being right.
My take: Volatility doesn’t care which way you’re betting — it just charges you for every trip back and forth.
Not advice. Just how I see it.