---
title: "Do stock market anomalies die when everyone trades them?"
description: "The cross-section of stock returns, momentum and asset pricing anomalies appear on 210 recent papers in the finance and economics journals, but only 14 of them carry a crowding, capacity, decay, replication or out-of-sample keyword. As quantitative funds trade the same signals, do anomaly returns shrink, and can crowding be measured in time?"
url: https://scholar4ai.com/ideas/factor-crowding-and-anomaly-decay
markdown_url: https://scholar4ai.com/ideas/factor-crowding-and-anomaly-decay.md
license: CC BY-NC 4.0 (https://creativecommons.org/licenses/by-nc/4.0/)
share_text: "The cross-section of stock returns, momentum and asset pricing anomalies appear on 210 recent papers in the finance and economics journals, but only 14 of them carry a crowding, capacity, decay, replication or out-of-sample keyword."
date: "2026-10-23"
updated: "2026-10-23"
status: "seed"
tags: ["finance", "asset pricing"]
keywords: ["factor investing", "momentum", "factor models", "stock return predictability"]
---

# Do stock market anomalies die when everyone trades them?

The cross-section of stock returns, momentum and asset pricing anomalies appear on 210 recent papers in the finance and economics journals, but only 14 of them carry a crowding, capacity, decay, replication or out-of-sample keyword. As quantitative funds trade the same signals, do anomaly returns shrink, and can crowding be measured in time?

## What prompted this

Since October 2025, 210 papers carry a factor-investing, factor-model, anomaly, momentum or cross-section-of-returns keyword (130 in finance journals, 38 in economics). Only 14 of them also carry a crowding, capacity, arbitrage-capital, decay, post-publication, replication or out-of-sample keyword. "Factor investing" appears on 8 papers and "stock return predictability" on 28.

## Questions

- Do anomaly returns fall after the strategies become available in cheap funds, beyond the decline after publication?
- Can crowding be measured from short interest, fund holdings and trading volume in the anomaly portfolios, and does it predict crashes such as the 2007 quant meltdown?
- Do the same anomalies decay in China's A-share market, where quantitative funds grew later?

## Data that could help

Anomaly portfolio returns (Open Source Asset Pricing, the Kenneth French library), fund holdings (13F filings), short interest and trading volume (CRSP).

## Next step

Build a crowding measure from 13F holdings for 20 anomalies and test whether it predicts their returns over the following year.

## Related research activity

*The keywords this note follows, in the tracked finance, accounting, economics, management, operations research and AI journals as of 2026-10-26*

| Keyword | Papers, last 30 days | Rank | Papers per month, Oct 23 – Oct 26* | Papers, last 36 months |
|---|---:|---:|---|---:|
| factor investing | 0 | – | 0, 0, 0, 0, 0, 1, 0, 2, 1, 0, 1, 1, 0, 3, 0, 1, 0, 1, 1, 1, 0, 0, 1, 1, 1, 1, 0, 2, 0, 0, 0, 1, 0, 1, 2, 0, 0 | 23 |
| momentum | 2 | #1303 | 3, 1, 1, 3, 1, 1, 2, 1, 1, 1, 2, 1, 1, 3, 1, 1, 2, 0, 1, 1, 0, 1, 0, 2, 3, 1, 2, 0, 1, 0, 0, 1, 1, 3, 1, 2, 1 | 46 |
| factor models | 1 | #2881 | 3, 1, 0, 3, 3, 2, 2, 3, 2, 0, 2, 5, 5, 2, 2, 1, 3, 1, 0, 2, 3, 1, 3, 2, 1, 1, 0, 0, 0, 2, 2, 0, 2, 2, 1, 2, 1 | 64 |
| stock return predictability | 0 | – | 3, 2, 1, 0, 0, 3, 2, 2, 0, 2, 3, 4, 2, 1, 2, 2, 5, 0, 3, 5, 2, 2, 5, 2, 2, 3, 3, 1, 3, 3, 2, 3, 3, 2, 1, 2, 0 | 81 |

## Cite this page

Scholar4AI. (2026). Do stock market anomalies die when everyone trades them?. Journal Research Rankings. Retrieved October 23, 2026, from https://scholar4ai.com/ideas/factor-crowding-and-anomaly-decay

```bibtex
@misc{scholar4ai-ideas-factor-crowding-and-anomaly-decay,
  author = {{Scholar4AI}},
  title = {Do stock market anomalies die when everyone trades them?},
  year = {2026},
  howpublished = {\url{https://scholar4ai.com/ideas/factor-crowding-and-anomaly-decay}},
  urldate = {2026-10-23},
  note = {Journal Research Rankings; data from OpenAlex (CC0); licensed CC BY-NC 4.0}
}
```

License: CC BY-NC 4.0 (https://creativecommons.org/licenses/by-nc/4.0/).