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Marginal ideas

Amir Sariri, John J. Horton

Status: Working paper

Last updated: 2026-05-06

Summary

Entrepreneurs crowd into promising startup ideas without internalizing the business-stealing costs they impose on one another. The paper shows that the least promising idea that still attracts funding—the marginal idea—can therefore offer the highest social return. It develops a sufficient statistic for this congestion and estimates it using 37,818 U.S. startups grouped into 2,045 idea niches.

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Presentations

NBER Summer Institute, Entrepreneurship, 2026

Coverage

Marginal Ideas, Expected Parrot

Cite

@unpublished{horton2026marginalideas,
  title = {{Marginal ideas}},
  author = {Sariri, Amir and Horton, John J.},
  year = {2026},
  url = {https://john-joseph-horton.com/papers/marginal-ideas/}
}

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