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Fathom

# Fathom Supply-side fees Methodology

## 1. Overview

Supply-side fees represent the portion of total fees that goes to liquidity providers (LPs) and lenders in the Fathom ecosystem. This metric aggregates supply-side fees from two business lines: Fathom DEX (decentralized exchange) and Fathom Lending (lending protocol). For Fathom DEX v2, liquidity providers receive 25% of trading fees (0.25% of trade value). For Fathom Lending, supply-side fees include interest payments to lenders and flash loan premiums, calculated based on reserve factor configurations.

## 2. Data sources

- **XDC blockchain event logs**: Parsed `Swap` events from Fathom DEX v2 pair contracts capturing trading activity
- **XDC factory events**: `PairCreated` events from Fathom DEX factory contracts for trading pair metadata
- **XDC transaction records**: Transaction data for user address identification and context
- **XDC lending events**: `FlashLoan` events from Fathom Lending v3 pool contracts for flash loan premiums
- **XDC lending configuration events**: `ReserveFactorChanged` events from lending pool configurator contracts
- **XDC treasury events**: `MintedToTreasury` events from lending pool contracts for protocol revenue tracking
- **External state data**: Fathom treasury accruals data from external state monitoring systems
- **End-of-day token price feeds**: USD price data for token value conversion
- **Token metadata**: Token decimals, symbols, and contract addresses for proper calculation formatting

## 3. Step-by-step calculation

### Component A: DEX supply-side fees
- **Purpose**: Calculate the portion of Fathom DEX trading fees that goes to liquidity providers
- **Logic**: Extract trading volume from XDC `Swap` events on Fathom DEX v2 pair contracts. For each swap, calculate the absolute change in both token amounts (`amount0In` - `amount0Out` and `amount1In` - `amount1Out`). Join with trading pair metadata from `PairCreated` events to get token decimals and fee tier information. Correct token amounts for decimals and convert to USD using end-of-day price feeds, taking the first available price between the two tokens in each pair. Calculate total fees by multiplying trading volume by the 0.3% fee tier. Apply the 25% split to determine the liquidity provider portion
- **Key fields**: `amount0In`, `amount0Out`, `amount1In`, `amount1Out` for swap amounts, `fee_tier` for fee percentage, `token0_address`, `token1_address` for token identification

### Component B: Lending interest supply-side fees
- **Purpose**: Calculate the portion of lending interest that goes to lenders rather than the protocol treasury
- **Logic**: Combine treasury accruals from external state data with treasury mints from `MintedToTreasury` events to calculate cumulative interest amounts. Use lag calculations to determine daily interest revenue by subtracting the previous day's cumulative amount. Join with reserve factor data from `ReserveFactorChanged` events, converting from basis points to decimal format. Calculate supply-side fees using the formula: daily_revenue ÷ reserve_factor × (1 - reserve_factor), which represents the portion allocated to lenders
- **Key fields**: `treasury_accruals` from external data, `amountMinted` from treasury events, `newReserveFactor` from configuration events

### Component C: Lending flash loan supply-side fees  
- **Purpose**: Calculate flash loan premiums that go to lenders
- **Logic**: Extract flash loan events from XDC `FlashLoan` events on Fathom Lending v3 contracts. Take the full premium amount as supply-side fees, as flash loan fees go entirely to lenders. Join with lending market metadata to get pool and token information
- **Key fields**: `premium` from flash loan events, `asset` for token identification, `amount` for loan size

### Final aggregation
- **Combining components**: Union DEX supply-side fees with both lending components (interest-based and flash loan fees). Group by timestamp, chain, and product dimensions
- **Currency conversion**: Apply USD conversion using end-of-day price feeds and correct for token decimals using the `convert_to_usd_and_correct_decimals` macro
- **Time aggregation**: Aggregate all fees to daily level using `timestamp_trunc` to day boundary
- **Final calculation**: Sum all supply-side fee components by day, chain, and product, then apply finalization macro for schema validation and zero-filling for missing periods

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

Portion of fees distributed to service providers or supply-side participants.

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Supply-side fees

Supply-side fees

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