Dominant Assurance Contracts

TL;DR:
Dominant Assurance Contracts (DACs) incentivize contributions to public goods by making it a win-win for early funders. If the project gets funded, the public good is delivered. If it doesn’t, funders get refunded with a bonus. The result: people have a dominant strategy to contribute.
Originally proposed by economist Alex Tabarrok, DACs are designed to overcome the public goods dilemma—where individuals benefit from others funding a good but hesitate to contribute themselves. By guaranteeing a return with upside if the project fails, DACs remove the risk of early support and help launch collective action.
Onchain, DACs are especially powerful because smart contracts can:
- Collect and hold funds in escrow
- Track progress toward a funding goal
- Return contributions with bonuses if the goal isn’t met
The bonus (sometimes funded by a sponsor or treasury) acts as an insurance policy and an incentive. When implemented well, DACs align individual rationality with collective benefit.
Best For
- High-impact public goods that struggle with early traction
- Campaigns needing critical mass to justify launch
- Environments where trust or risk aversion blocks early funding
- Funding experiments with game-theoretic framing
Good At
- Encouraging early contributions
- Reducing risk for first movers
- Solving collective action problems
- Creating strong incentives to fund public goods
Dependencies / Requirements
- Smart contracts that can hold, refund, and disburse funds
- A clear funding threshold and timeline
- Bonus pool (funded by treasury, sponsor, or pre-set logic)
- Transparent criteria for project success/failure
Not Good At
- Long-term or recurring funding
- Projects with ambiguous outcomes or costs
- Use cases where bonus funding is hard to secure
- Environments with very low engagement
Who Should Use It?
- DAOs or communities trying to bootstrap funding for a new initiative
- Public goods projects that have clear costs and benefits
- Ecosystems wanting to experiment with economic incentives for early contributors
- Protocols offering bonus-backed funding commitments via smart contracts
Example Use Cases
- A community launches a DAC to fund a local mesh network: if the goal is hit, the network is built; if not, contributors get refunded with a 10% bonus
- A DAO backs early contributors to a new tool with a DAC—either the project gets built or contributors earn a return
- A public goods coalition creates DACs to kickstart regional mutual aid projects with low initial traction