I put 36 years of World Cup squads into one CSV, and the Bosman effect is impossible to miss
Here is a question I could not answer from memory, so I went looking for data: when you watch a national team at the World Cup, how many of those players actually play their club football abroad?
The intuitive guess is "a few stars." The real answer, for 2026, is roughly three out of four. In 1990 it was one in four. I cleaned the squad data into a small open CSV (CC BY 4.0) so the trend is easy to check, and this post is the short version of what it shows.
One ruling, one inflection point
The line does not climb smoothly. It bends sharply right after 1995, the year of the Bosman ruling (European Court of Justice, Case C-415/93). That decision scrapped EU limits on foreign players and allowed free transfers at the end of a contract. In one stroke, professional footballers became ordinary workers in the single market.
You can see the bend in two lines of Python:
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)
df.plot(x="year", y="foreign_based_share_percent", marker="o", legend=False)
| Year | Foreign-based share |
|---|---|
| 1990 | 26.2% |
| 2002 | 38.1% |
| 2014 | 53.9% |
| 2026 | 72.2% |
The part I did not expect
I assumed the football powers would lose the most players to richer leagues abroad. The data says the opposite. The nations with the strongest domestic leagues keep their players at home:
| Nation | Foreign-based share, 2026 |
|---|---|
| Switzerland | 100% |
| Argentina | 94% |
| Brazil | 89% |
| France | 83% |
| Germany | 33% |
| England | 22% |
England and Germany retain the most, because the Premier League and Bundesliga are destinations, not departure lounges. Talent concentrates where the market is biggest. The free movement that Bosman unlocked did not spread talent evenly, it pooled it.
Data and sources
"Foreign-based" = a squad player under contract at a club outside his national team's country at tournament time.
Player citizenship and clubs from transfermarkt.de; squads from FIFA World Cup lists.
Open dataset: https://github.com/DatapulseResearch/world-cup-players-abroad
Full study with all charts: https://www.finalarm.de/studies/world-cup-players-abroad
Grab the CSV and slice it your own way. If you find something the prose missed, tell me.