Role of the vault
The Burn Vault is the contract that holds, on Arbitrum, the wBTC reserve backing the protocol’s base floor. The current balance is 382.82 wBTC, public on Arbiscan. The The Burn Vault Boost, described below, is a second vault with its own backing of 37.43 wBTC; together, the two hold 420.25 wBTC.
The contract serves three functions:
- Reserve: accumulates the daily deposits from mining.
- Floor: sets the minimum redemption price of each EVA via the Burn Price formula.
- Redemption: delivers wBTC in exchange for burning EVA, at any time.
Immutability and no administrative withdrawal
The contract is immutable: there is no multisig, no admin key, and no upgrade function. After deployment, the code cannot be changed.
The only operation that transfers wBTC out of the vault is redemption, which necessarily burns the corresponding EVA. No alternative path exists in the code. This restriction is the central point verified by the Audits.
Independent verification
The contract code is public and verified on Arbiscan. Reading its functions makes it possible to confirm that no withdraw exists without burn.
The Burn Price
The Burn Price is the minimum redemption value of each EVA, in wBTC, guaranteed by the contract. It is a direct division, recalculated every block:
Two events change this value, and only two. Mining deposits increase the numerator and raise the floor. Redemptions reduce numerator and denominator in the same proportion and keep the floor unchanged. No operation can lower it; the proof is in the Mathematical model.
Numerical example
The values below are round and illustrative, to follow the mechanics end to end. The protocol’s real state is at the top of this page and in the Overview:
| Event | wBTC | EVA | Burn Price |
|---|---|---|---|
| Launch | 75.00 wBTC | 21,000,000 EVA | 357 sats |
| +30 days of mining (+9 wBTC) | 84.00 wBTC | 21,000,000 EVA | 400 sats |
| Redemption of 500,000 EVA (−2 wBTC) | 82.00 wBTC | 20,500,000 EVA | 400 sats |
| +30 days of mining (+9 wBTC) | 91.00 wBTC | 20,500,000 EVA | 444 sats |
- The redemption did not change the floor: 2 wBTC and 500,000 EVA left, in the same proportion.
- The second month of mining raised the floor faster than the first (+44 sats versus +43 sats): the same 9 wBTC, divided among 20.5 million tokens instead of 21 million, yield more per token.
The long-term effect of burns
Every burn is permanent. So far, 2,886,083 EVA have left circulation. Since the supply only shrinks and deposits keep coming in, each remaining token represents a growing fraction of the vault.
Effect on future deposits
A redemption does not change the floor at the moment it occurs, but it reduces the number of tokens among which subsequent deposits are divided: the same deposit then raises the floor by more sats per token.
The Burn Vault Boost
When the backing is divided by the entire supply, each deposit is diluted across millions of tokens and the floor rises slowly. The Burn Vault Boost is a separate vault that applies the same formula to a guaranteed quota of 148,776 EVA, instead of the whole supply. With a smaller denominator, the per-token floor of this quota is higher and responds more to each new deposit.
The difference in sensitivity, in round, illustrative numbers:
| Vault | Tokens | Effect per deposit |
|---|---|---|
| Core (entire supply) | 21,000,000 | +5 sats |
| Boost (quota of 100,000) | 100,000 | +1,000 sats |
Within the quota, the same deposit produces a per-token effect roughly 200 times greater. It is the same division, applied to a smaller denominator.
The current state of the quota:
- Guaranteed quota
- 148,776 EVA
- Already burned from the quota
- 79,047 EVA
- Remaining eligible EVA
- 69,729 EVA
- wBTC in the Boost vault
- 37.43 wBTC
- Guaranteed floor (Boost)
- 53,680 sats
The floor shown is the burn quote read from the Boost contract itself, which publishes on-chain how many EVA the quota still covers and how much it pays for each one. As the quota is consumed, the remaining wBTC covers fewer EVA and the floor rises; the current value is 53,680 sats. The contract also accepts coverage expansions, which is why the total guaranteed today exceeds the original 100,000 EVA.
Scope of the guarantee
The Boost defines an objective redemption floor for the remaining quota. It does not guarantee a market price: when the market trades above the floor, the Boost does not interfere. The quota is finite by design; the guarantee applies to the eligible EVA still remaining in it.
Market scenarios
The guaranteed floor currently operates close to the market price (spot ~US$ 46.35, floor ~US$ 46.26). Since the floor never decreases, each market direction activates a distinct mechanic:
- Rising market: the floor keeps climbing with deposits, below the price. When the floor reaches a position’s entry price, the minimum BTC redemption comes to cover the amount paid.
- Falling market: if the price drops below the floor, an arbitrage opens: buy on the market and redeem through the Boost, at an immediate profit. The operation burns supply and generates buying pressure for as long as the price stays below the floor.
- Sideways market: the floor keeps rising with each mining deposit until it reaches the market price, at which point one of the scenarios above takes over.
In any scenario, the Core base floor remains underneath, as the minimum redemption value of any EVA, inside or outside the quota. The current campaign terms are on the official Boost page: boost.evervaluecoin.com.