> ## Documentation Index > Fetch the complete documentation index at: https://docs.defindex.io/llms.txt > Use this file to discover all available pages before exploring further. # Boost > You fund it, and every cent of it reaches your depositors. Fee control can trim yield that sits above a target. It cannot create yield that is not there. A boost campaign can, because you fund it. ## How a campaign runs You fund a budget that is held for your vault, in the vault's own asset. While the vault sits below its target and the budget still has money in it, funds move from there into the vault, which raises what every depositor holds. Spending stops when the budget does, and the vault returns to its organic rate. Campaigns are per vault and supported for single asset vaults. We register the campaign for you, and once it is active anyone can add funds to it. ## What a boost costs **A boost carries no vault fee.** It arrives as a plain transfer rather than as strategy gains, so nothing is locked on it. Every unit you put in reaches your depositors, and neither you nor DeFindex is paid on it. That makes the fee floor underneath a real decision rather than a formality: * **A floor of zero** hands your users all of the organic yield before the campaign spends anything, and nobody is paid while the vault sits below target. * **A floor above zero** keeps your fee running through the shortfall, which means the campaign has more ground to cover. [Talk to our team](https://cal.com/esteblock) before planning a campaign you expect to earn from, or before setting a floor above zero. The arithmetic turns on your target, your strategy mix and the size of the budget, and it is worth an hour with your numbers. ## Without Stable APY A campaign does not need Stable APY. A vault on an ordinary fixed fee can run one against a target we keep on our side, which is the right shape when you want to lift a rate for a season without handing over control of your fee. ## Custody Boosts only move money in. Nothing here can take a depositor's funds out of the vault or delay a withdrawal. Your budget is held separately per vault, and whatever is left of it can be sent back to an address you name. See [Risks and Audits](/advanced-documentation/risks-and-audits#custody). ## Audit Audited by [Runtime Verification](https://runtimeverification.com/audits) in July 2026, together with the fee proxy. See [Risks and Audits](/advanced-documentation/risks-and-audits). Fund a campaign and read its status.