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Maria-Luise Volkmar
Maria-Luise Volkmar

Posted on • Originally published at finalarm.de

The Bosman Effect, in one open dataset: how World Cup squads went global (1990 to 2026)

In 1990, roughly one in four players at the FIFA World Cup was based at a club outside the country his national team represented. At the 2026 edition it is nearly three in four. That is a structural shift in a labour market, and it has a surprisingly precise cause: a 1995 court ruling.

I pulled the squad data together, cleaned it into a small CSV, and put it on GitHub under CC BY 4.0 so anyone can check the trend or build on it. This post walks through what the data shows and how to reproduce the headline chart in a few lines of Python.

The headline number

Share of foreign-based players across World Cup squads:

Year Foreign-based share
1990 26.2%
2002 38.1%
2014 53.9%
2026 72.2%

The inflection point is the Bosman ruling (European Court of Justice, 15 December 1995, Case C-415/93), which abolished EU limits on foreign players and allowed free transfers at contract end. Professional footballers became, legally, ordinary workers with the right to work anywhere in the single market.

Reproduce it

The dataset is two CSVs. Loading the time series straight from GitHub:

import pandas as pd

url = ("https://raw.githubusercontent.com/DatapulseResearch/"
       "world-cup-players-abroad/main/data/"
       "world_cup_squads_foreign_based_share_1990_2026.csv")

df = pd.read_csv(url)
ax = df.plot(x="year", y="foreign_based_share_percent",
             marker="o", legend=False,
             title="Foreign-based players in World Cup squads, 1990 to 2026")
ax.set_ylabel("% of squad based abroad")
ax.axvline(1995, linestyle="--", alpha=.4)  # Bosman
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One line and you can see the post-1995 climb.

The counterintuitive part

You might expect the strongest nations to export the most players. The opposite is true. The 2026 per-country table (world_cup_2026_foreign_based_by_country.csv) shows the strongest domestic leagues keep their talent at home:

Nation Foreign-based share, 2026
Switzerland 100%
Argentina 94%
Brazil 89%
France 83%
Germany 33%
England 22%

England and Germany, with the strongest leagues, retain the most. Talent follows the biggest market, not the passport.

Data and method

If you do something with the data (a different cut, a model, a better chart), I would love to see it in the comments.

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