What it is
An NFT vault is a smart contract that takes custody of one non-fungible token (or a small bundle of them) and, in exchange, mints a supply of fungible ERC-20 tokens representing fractional claims on it. Instead of one wallet owning a $500,000 digital collectible outright, hundreds of wallets can each hold a tradeable slice of it. The vault is the piece of infrastructure everything else — pricing, voting, buyouts — is built on top of.
How it works
- An NFT owner deposits their token into the vault contract, which takes exclusive custody: the NFT can no longer be transferred except through vault-defined exit paths.
- The vault mints a fixed supply of ERC-20 "fractional" tokens and sends them to the depositor, who typically then sells or distributes most of them to raise liquidity or share ownership.
- Fraction holders now collectively "own" the underlying NFT in proportion to their token balance, and the vault contract tracks this relationship on-chain — no off-chain legal wrapper is needed for the token mechanics themselves.
- The vault exposes governance hooks (e.g., setting a reserve price, voting on a sale) so fraction holders can act collectively without any single holder having custody.
- The NFT is released from the vault only when an exit condition is met — most commonly a buyout auction where someone offers to buy out all fractions at or above the reserve price, or a governance vote to sell.
- Once triggered, the vault is unwound: the buyer receives the NFT, and fraction holders redeem their tokens for a pro-rata share of the sale proceeds (or can choose to keep fractions if the vault supports partial/no-sale outcomes, depending on implementation).
Why designers use it
- Makes illiquid, high-value NFTs accessible to buyers who can't or won't spend the full price of one item.
- Creates a liquid secondary market (the ERC-20 fraction) for an asset class that otherwise trades one-off, peer-to-peer.
- Lets a community collectively own culturally or financially significant NFTs (e.g., a rare collectible) without a single custodian.
- Separates custody (the vault) from governance (fraction-holder votes), reducing single-point-of-failure risk relative to one person holding the NFT and everyone else trusting them.
Failure modes
- If the fraction supply is thinly traded, the token price can drift far from any reasonable value of the underlying NFT, so the "market cap" of fractions misprices the actual asset.
- A whale can quietly accumulate a majority of fractions and force an undervalued buyout or block a fair one, extracting value from smaller holders.
- Vault contracts holding a single, illiquid, hard-to-appraise asset are attractive targets for governance attacks or reserve-price manipulation, since there's no independent price feed to check against.
- If no buyout ever clears, fraction holders can be stuck indefinitely with a token that has no path to realizing the underlying value.
- Smart-contract bugs in custody or redemption logic are catastrophic here because the entire value of the vault is concentrated in one non-fungible asset with no diversification.
What to check before using it
- Confirm the vault contract has been audited specifically for custody and redemption logic, since a bug there risks total loss of the underlying asset.
- Check how reserve price and buyout mechanics are set and whether they resist manipulation by a large fraction holder.
- Look at historical trading volume and depth of the fraction token before assuming its price reflects the NFT's real value.
- Understand the exit paths precisely: what happens if no buyout ever occurs, and whether fractions can be redeemed any other way.
- Verify what happens to fees, royalties, or future utility tied to the original NFT once it's vaulted — these rights don't always carry over automatically.