Quadratic funding

A matching fund for public goods: projects receive matching money proportional to the square of the sum of the square roots of individual contributions, so broad support counts more than a few large donations.

Buterin, Hitzig and Weyl (2019) show that, in theory, the rule funds public goods at efficient levels when a matching pool covers the gap.

• Gitcoin has run quadratic-funding rounds for open-source software since 2019.
• Several blockchain ecosystems and civic projects have adopted variants.

Results depend on robust identity: one person splitting donations across accounts can capture matching funds. Matching pools must be refilled from outside, so the mechanism allocates subsidies rather than raising them.

Quadratic funding has distributed real money to many small projects. Independent evaluation of whether it funds better projects than alternatives is limited.