Overcollateralized borrowers deposit funds into Sky and receive DAI stablecoin.

Sky is a non-custodial stablecoin protocol built on Ethereum. Sky (previously MakerDAO) was founded by Rune Christensen and launched in 2015.

SKY tokenholders own and govern the protocol. They currently take all of the total interest and PSM fees paid by borrowers (revenue). Sky’s investors include a16z, Polychain, IOSG Ventures, etc.

governance

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etherscan

website

Stablecoin issuers

Sky | Fees and revenues breakdown

# Sky Outstanding supply Methodology

## 1. Overview

Sky outstanding supply represents the net circulating supply of Sky's stablecoin (DAI/USDS) after excluding idle balances held in various protocols and yield strategies. The metric answers the question: "How much Sky stablecoin is actually circulating in the market versus sitting idle in Sky-controlled or Sky-integrated protocols?"

The calculation uses the formula: total debt minus exclusions. Total debt represents the gross outstanding supply from Sky's vault system, while exclusions remove amounts that are not actively circulating, such as idle balances in lending protocols, stability modules, and cross-chain bridge contracts.

## 2. Data sources

- **Sky VAT contract state data**: Contract state calls to Sky's VAT (Vault Engine) contract tracking the `debt()` function, which returns total outstanding debt across all vaults
- **Ethereum token transfer events**: Parsed `Transfer` events for spDAI, variableDebtDAI, DAI, USDS, and sUSD tokens to track balance changes in specific contracts
- **Cross-chain token transfers**: Parsed `Transfer` events for USDS and sUSD tokens on Arbitrum and Base networks to track L2 idle balances
- **Morpho protocol state data**: Contract state snapshots tracking Sky's DAI shares in Morpho idle markets, total shares, and total supply assets
- **Token metadata**: Token contract information including decimal places for proper amount conversions
- **End-of-day price feeds**: Daily closing prices for USD conversion of all components

## 3. Step-by-step calculation

### Component A: Total sky debt
- **Purpose**: Calculates the gross outstanding debt from Sky's vault system representing total stablecoin supply
- **Logic**: Retrieves daily snapshots of the `debt()` function from Sky's VAT contract on Ethereum. The VAT contract is the core engine that tracks all outstanding debt across Sky's collateralized debt positions. Values are stored with 45 decimal precision and converted to standard decimals by dividing by 1e45
- **Key fields**: `state_value` from VAT debt function calls, converted to standard decimal representation as `amount`

### Component B: Spark protocol idle DAI calculation
- **Purpose**: Calculates the amount of DAI that Sky holds idle in the Spark lending protocol
- **Logic**: Tracks `Transfer` events for spDAI tokens to identify when Sky deposits or withdraws from Spark. Calculates total spDAI supply by monitoring mint and burn events (transfers from/to zero address). Monitors variable debt DAI supply similarly. Sky's idle DAI equals the net spDAI supply minus variable debt, multiplied by Sky's proportional share of total spDAI supply based on Sky's spDAI balance
- **Key fields**: `value` amounts from spDAI and variableDebtDAI transfer events, converted using token decimals to calculate `balance` and `supply` values

### Component C: Morpho idle market DAI share
- **Purpose**: Determines Sky's share of DAI deposited in Morpho idle markets
- **Logic**: Uses contract state data to track Sky's shares in Morpho idle markets divided by total shares outstanding. Multiplies this percentage by the total supply assets in the idle market to determine Sky's actual DAI amount. State values are converted from 18 decimal precision
- **Key fields**: `state_value` for Sky's DAI shares, total DAI shares, and total supply assets from Morpho contract states

### Component D: LitePSM DAI buffer tracking
- **Purpose**: Tracks DAI balance held as buffer in Sky's LitePSM (Lite Peg Stability Module)
- **Logic**: Monitors `Transfer` events for DAI tokens moving to and from the LitePSM contract address. Positive amounts represent DAI flowing into the PSM (increasing buffer), negative amounts represent DAI flowing out (decreasing buffer). Daily balance changes are aggregated and running totals calculated
- **Key fields**: `value` from DAI transfer events involving the LitePSM contract, converted using DAI token decimals

### Component E: Cross-chain idle balances
- **Purpose**: Tracks USDS and sUSD balances held idle in PSM3 and ALM proxy contracts on Arbitrum and Base
- **Logic**: Monitors `Transfer` events for USDS and sUSD tokens on Arbitrum and Base networks to track deposits and withdrawals from PSM3 and ALM proxy contract addresses. Positive transfers represent tokens flowing into these contracts, negative transfers represent outflows. Daily balance changes are aggregated into running totals for each chain and token combination
- **Key fields**: `value` from USDS and sUSD transfer events on Layer 2 networks, converted using respective token decimals

### Final aggregation
- **Combining components**: All exclusion components (Spark idle DAI, Morpho idle DAI, LitePSM buffer, and cross-chain idle balances) are summed together after USD conversion
- **Currency conversion**: Each component is converted to USD using end-of-day price feeds matched by timestamp, with appropriate token-to-USD exchange rates applied
- **Time aggregation**: All components use daily timestamps with data aggregated to daily boundaries. Missing dates are filled forward to ensure continuous time series
- **Final calculation**: Outstanding supply equals total VAT debt minus the sum of all USD-converted exclusions. The result represents the net circulating supply of Sky stablecoin after removing idle balances across various protocols and chains

*This methodology was automatically generated by Token Terminal's methodology analyzer.*

Circulating supply of stablecoins issued by the project.

SkySKY

Outstanding supply

Outstanding supply

Competitive landscape

Chain breakdown