# What Happens If You Chase Spike Stocks — All 22,474 Cases Tested
- Source: FoldAlpha Research (https://app.foldalpha.com/en/research/spike-chasing) · Published: 2026-09-01 · Series: Myth Testing 5

Trading spike stocks is the most popular approach among Korean retail investors. We tested the maxim
"get on the horse that is already running" against the full set of Korea Exchange daily data. The result pointed the same
direction no matter how we changed the conditions.

## Method

- **Signal**: daily change of +13% or more, volume of 100,000 shares or more, price of 1,000 won or more (all KOSPI and KOSDAQ stocks)
- **Entry / exit**: buy at the close on the spike day, hold for 20 trading days — a direct reproduction of "you see today's spike and you buy"
- **Verdict**: excess return versus the market average over the same period

## Results — no variant survived

| Signal | Sample | 20-day excess vs market | Beat-market rate |
|---|---|---|---|
| **Chasing the close on the spike day (base case)** | **22,474** | **-7.5%p** (median -8.9%) | **34.8%** |
| Chasing only spikes with first-day news ignition (2 years) | 4,141 | median -8.9% | win rate 31% |
| "Perfect pattern" (day +15% · prior 5 days +10% · volume 3×) | 472 | -3.0% | 26% |
| Spike after capitulation selling (a drop of -8% or more) | 4,482 | -7.4%p | 35% |
| Micro-cap spikes (market cap of 100 billion won or less) | 12,088 | **-10.1%p** | 29% |
| Spikes preceded by traces in both price and volume | 3,895 | **-11.4%p** | 33% |

The key is the third row. Picking the "ideal scenario" the chart textbooks describe — a spike accompanied by a prior
run-up and a volume surge — and buying into it produced a win rate of **26%, among the lowest of all**.
The better the pattern looked, the more the move had already happened.

## What these numbers say

The gains from a spike belong to whoever was already in **before** it. By the time you enter after seeing the spike,
on average you are the exit liquidity for the person ahead of you. A 20-day median of -8.9% is not chance; it is close to
the structural expected value of this game.

"Then why not get in before the spike?" is the natural next question. We tested that too —
it is covered in the [next article](/en/research/spike-front-running).

## Limitations

- This is based on a 20-day holding period. Same-day day trading (minute-level) is outside the scope of this test.
- The verdict is relative to the market average, so on an absolute-return basis these can be positive in a rising market (still worse than simply buying the market).

## Data sources

- Full daily price data from the Korea Exchange. Daily top movers can be checked in the [closing report](/daily)

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This article documents tests on historical data for informational purposes only. It is not investment advice or a recommendation to buy or sell any security. Past test results do not guarantee future returns.