Short Squeezes Explained: How They Happen on the ASX

Few events in the stock market generate as much excitement — and as much confusion — as a short squeeze. They can send share prices rocketing in a matter of days, catching short sellers off-guard and rewarding shareholders who held on. But what actually causes them, and can you see one coming?

The Mechanics of a Short Squeeze

A short squeeze occurs when a heavily shorted stock begins to rise in price, forcing short sellers to buy back shares to close their positions. This buying pressure pushes the price even higher, which in turn forces more shorts to cover — creating a self-reinforcing feedback loop.

Here's how it typically unfolds:

1. Setup: A large number of traders have short positions open on a stock, often exceeding 10% of shares on issue.
2. Catalyst: Something shifts sentiment — an earnings beat, a takeover rumour, a positive clinical trial result, or simply a wave of retail buying.
3. Covering begins: As the price rises, short sellers face mounting losses. Their brokers may issue margin calls, forcing them to buy shares at market price.
4. Acceleration: Each wave of covering drives the price higher, triggering further margin calls and stop-losses.
5. Peak: Eventually the buying pressure exhausts itself and the price stabilises — often at a significantly higher level than where it started.

Key Indicators to Watch

1. Short Interest Above 10%

Stocks with very high short interest as a percentage of total shares on issue are the most likely candidates for a squeeze. On the ASX, you can track this daily through ASIC's short position reports — or more easily through Shorted.com.au.

2. Days to Cover

This metric divides total short positions by average daily trading volume. A "days to cover" ratio above 5-7 suggests it would take a week or more for all short sellers to exit, creating significant squeeze potential.

3. Low Free Float

If a company has a small free float — meaning insiders, institutions, or strategic holders own most of the shares — the available shares for short sellers to buy back become scarce, amplifying squeeze dynamics.

4. Rising Borrow Costs

When the cost to borrow shares for shorting rises sharply, it signals high demand for shorts and limited supply — a setup ripe for a squeeze if sentiment reverses.

Notable ASX Short Squeezes

Fortescue Metals (FMG)

Fortescue has been one of the most consistently shorted stocks on the ASX, with short interest frequently exceeding 8-10% of shares on issue. On multiple occasions, rallies in iron ore prices combined with high short interest have triggered rapid price surges as bears scrambled to cover.

Zip Co (ZIP)

The buy-now-pay-later sector saw dramatic short squeeze dynamics during 2020-2021. ZIP was heavily shorted due to profitability concerns, but waves of retail investor enthusiasm drove sharp rallies that forced covering.

Pilbara Minerals (PLS)

The lithium miner experienced squeeze-like dynamics as lithium prices surged in 2022. Short sellers who had bet against the sector were caught on the wrong side of a commodity super-cycle.

How to Spot Squeeze Potential on Shorted.com.au

Using our platform, you can identify potential short squeeze candidates by:

• Monitoring the Top Shorted stocks: Stocks consistently above 10% short interest are prime candidates
• Tracking week-over-week changes: A rising stock price combined with high short interest suggests covering is starting
• Watching the Risers and Fallers: Sudden drops in short interest for heavily shorted stocks may indicate the early stages of a squeeze
• Cross-referencing with volume: Unusual volume spikes on a heavily shorted stock deserve immediate attention

The Risks of Playing a Short Squeeze

Before you rush to buy every heavily shorted stock, remember:

• Most heavily shorted stocks are shorted for a reason — the market may be right about fundamental problems
• Timing is nearly impossible — you might buy in just as the squeeze peaks
• Volatility cuts both ways — squeezes can reverse just as quickly as they form
• Institutional shorts have deep pockets — they can absorb losses that would wipe out retail traders

The best approach is to use short interest data as one signal among many, not as a standalone trading strategy.

What ASIC Data Tells Us

ASIC's mandatory reporting requirements mean Australia has some of the most transparent short selling data in the world. Every net short position above the reporting threshold is published daily. This transparency is a significant advantage for Australian investors compared to many other markets where short positions are reported less frequently.

By tracking this data consistently — which is exactly what Shorted is built to do — you can build an understanding of which stocks are under pressure, which sectors are seeing increased bearish sentiment, and where the conditions for a squeeze might be forming.

Conclusion

Short squeezes are dramatic, exciting, and dangerous in equal measure. Understanding the mechanics helps you navigate them — whether you're hoping to benefit from one, trying to avoid being caught in one, or simply want to understand why a stock is suddenly skyrocketing.

The key is always the data. Track short interest, watch for catalysts, and never bet more than you can afford to lose.

Monitor ASX short squeeze candidates →

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This content is for informational purposes only and does not constitute financial advice. Short squeezes involve significant risk and investors should conduct their own research before making investment decisions.