Short selling
With a short sale, you borrow securities, sell them, and buy them back later. The possible gain is capped; the possible loss isn't.
You borrow a stock, sell it for a hundred euros, and hope to buy it back later for eighty. The difference is your gain, minus the borrowing fee.
The imbalance is the core of it: a stock can fall to zero at most, so your gain is capped at a hundred euros. There's no ceiling going up, so your loss is unlimited.
There's also time pressure. You pay ongoing borrowing fees, and the lender can recall the shares. So you can be forced to close even if you'd have been proven right.
And there's the short squeeze: if many people are betting on a decline and the price rises instead, everyone has to buy back at once. That pushes the price up further and can cost a multiple of the original stake in a short time.
The asymmetric payoff structure follows directly from the price floor of zero. Maximum gain equals the sale proceeds; maximum loss is theoretically unlimited. This asymmetry means position-sizing rules for short positions need to be stricter than for long positions, since the loss isn't bounded by the stake.
There are structural costs on top: borrowing fees, which can be substantial for heavily shorted stocks, plus dividend compensation payments to the lender. The recallability of borrowed shares also creates a forced-close risk that's independent of price movement.
A short squeeze forms when a price rise triggers covering purchases that amplify the rise. Vulnerability grows with the share of shorted stock relative to the freely tradable float, and with low liquidity. The mechanism structurally matches a liquidation cascade in leveraged positions, just with the sign reversed.
Summary
- Gain is capped, loss is theoretically unlimited.
- Borrowing fees and recallability create time pressure.
- A short squeeze works like a liquidation cascade running upward.
Did you get it?
Why is the loss unlimited in a short sale?
Because the price can rise indefinitely, while it can only fall to zero.
What risk exists regardless of price?
The lender recalling the borrowed shares, forcing a close.
What triggers a short squeeze?
Covering purchases during a price rise amplify the rise, especially with high short interest and low liquidity.
Related
- GameStopCase Studies
- What an ETF isStage 0
- LiquidationStage 2