Fee management

This page covers the smart contract implementation details. See Glossary.

The FeeManager is an optional contract that you can attach to a Multi-Vehicle or Conduit at deployment time. It automates fee calculation and collection across the vehicle lifecycle. Once set during initialization, the FeeManager cannot be changed or removed, ensuring predictability for users. You can share a single FeeManager across multiple Multi-Vehicle contracts to maintain consistent fee behavior and centralize configuration changes.

The 4 fee types

Railnet supports four distinct fee types, each calculated and applied at different points in the vehicle lifecycle.

Performance fee (on earnings)

A fee charged on gains above the high water mark. You only collect when the strategy makes money.

High Water Mark: $1,000,000
Current Assets:  $1,100,000
Earnings:        $100,000

// If performance fee = 20%:
// Fee = $100,000 * 20% = $20,000 (minted as shares)
// The high water mark moves to the post-operation total assets
// when the vehicle calls onUpdate at the end of the operation.

// Formula:
// earnings = max(0, currentTotalAssets - lastTotalAssets)
// performanceFeeAssets = earnings * performanceFeeBps / 10000

// Coming soon

Best for: Hedge fund-style fee models, performance-aligned compensation. Users only pay when the strategy profits.

If the strategy loses value, no performance fees are collected until the share price recovers past the previous high water mark.

Management fee (time-based)

An annualized fee prorated by the time elapsed since the last fee-cache update (onUpdate). Charged regardless of performance.

Total Assets:     1,000,000 USDC
Management Fee:   2% annual (200 bps)
Time Elapsed:     30 days (2,592,000 seconds)

// Fee = totalAssets * managementFeeBps * timeDelta / (10000 * 31536000)
// Fee = 1,000,000 * 200 * 2,592,000 / (10000 * 31536000)
// Fee = ~1,644 USDC worth of shares minted

// Coming soon

Best for: Covering ongoing operational costs (gas, infrastructure, monitoring). Provides a predictable revenue stream.

Management fees accrue continuously based on block.timestamp. The first operation after a long idle period may mint substantial shares.

Deposit fee (entry fee)

A fee charged when users deposit assets. Deducted from shares received during the unlock phase.

User Deposits:     10,000 USDC
Share Price:       $1.00/share
Expected Shares:   10,000 shares

// If deposit fee = 1%:
// Fee = 10,000 * 1% = 100 shares
// User Receives:   9,900 shares
// FeeManager Gets: 100 shares

// Coming soon

Best for: Discouraging short-term “hot money” deposits, one-time onboarding costs, aligning incentives for long-term holders.

Redeem fee (exit fee)

A fee charged when users redeem shares. Deducted from assets received during the unlock phase.

User Redeems:      10,000 shares
Share Price:       $1.00/share
Expected Assets:   10,000 USDC

// If redeem fee = 0.5%:
// Fee = 10,000 * 0.5% = 50 USDC
// User Receives:   9,950 USDC
// FeeManager Gets: 50 USDC

// Coming soon

Best for: Discouraging short-term withdrawals, compensating for liquidity management costs, protecting remaining holders from withdrawal impact.

When fees are applied

Fee type	Calculation point	Applied as
Performance	`onOperations` (during `create`)	Shares minted to FeeManager
Management	`onOperations` (during `create`)	Shares minted to FeeManager
Deposit	`applyFees` (during `unlock`)	Reduced shares paid to user
Redeem	`applyFees` (during `unlock`)	Reduced assets paid to user

Fee recipients and distribution

Fees can be distributed to multiple recipients with configured percentage splits:

FeeRecipient[] memory recipients = new FeeRecipient[](3);
recipients[0] = FeeRecipient({
    target: operatorAddress,
    shareBps: 6000  // 60% to operator
});
recipients[1] = FeeRecipient({
    target: daoTreasuryAddress,
    shareBps: 3000  // 30% to DAO treasury
});
recipients[2] = FeeRecipient({
    target: developerAddress,
    shareBps: 1000  // 10% to developers
});
// Must sum to exactly 10,000 (100%) and be sorted
// strictly ascending by target address

feeManager.setFeeRecipients(recipients);

// Coming soon

Example configurations

Hedge fund model
Index fund model
Active management
Long-term capital

Fees({
    performanceFeeBps: 2000,  // 20% of profits
    managementFeeBps: 0,
    depositFeeBps: 0,
    redeemFeeBps: 0
})

// Coming soon

Aligned with user returns. You only charge on gains.

Fees({
    performanceFeeBps: 0,
    managementFeeBps: 50,  // 0.5% annual
    depositFeeBps: 0,
    redeemFeeBps: 0
})

// Coming soon

Low-cost passive strategy with minimal management overhead.

Fees({
    performanceFeeBps: 1000,  // 10% of profits
    managementFeeBps: 200,    // 2% annual
    depositFeeBps: 50,        // 0.5% entry
    redeemFeeBps: 50          // 0.5% exit
})

// Coming soon

Professional active management with entry/exit barriers.

Fees({
    performanceFeeBps: 0,
    managementFeeBps: 0,
    depositFeeBps: 100,  // 1% entry fee
    redeemFeeBps: 0
})

// Coming soon

Encourages committed capital with free exit.

Configuration

Prerequisites

You need the following roles on your External Access Control, scoped to the Fee Manager contract:

Role	Purpose
`FEE_MANAGER_SET_FEES`	Update fee percentages
`FEE_MANAGER_SET_FEE_RECIPIENTS`	Update the list of fee recipients
`FEE_MANAGER_DISPATCH_ERC20`	Distribute collected fees to recipients

Set fee percentages

Configure the four fee rates. Values must not exceed the maximum limits set during Fee Manager deployment.

FeeManager.Fees memory newFees = FeeManager.Fees({
    performanceFeeBps: 1000,  // 10% performance fee
    managementFeeBps: 200,    // 2% annual management fee
    depositFeeBps: 0,         // No deposit fee
    redeemFeeBps: 50          // 0.5% redeem fee
});

feeManager.setFees(newFees);

// Coming soon

Fee values must not exceed the maxFees ceiling defined at deployment. Attempting to set fees above the maximum reverts with FeeTooHigh. You can query the current maximums with feeManager.maxFees(). Performance and management ceilings may go up to 10,000 bps, but deposit and redeem ceilings are themselves capped at 9,999 bps: a 100% transactional fee is not reversible by reverseFees.

Fee configuration IDs

Every accepted setFees call derives a configId — keccak256(abi.encode(fees)) — stores the Fees struct under it, and makes it the current configuration. feeManager.fees() returns (configId, Fees) for the current one, and feeManager.fees(configId) returns any past one. Passing bytes32(0) to the config-scoped functions resolves to the current configuration; an unknown id reverts with NonExistingConfigId. This versioning is what keeps asynchronous queries consistent:

Transactional fees. The vehicle pins the active configId when a query is created and reads it back on unlock, so a fee change mid-flight never applies retroactively to an in-flight query. Read it with vehicle.feesConfigId(query) — or conduit.feesConfigId(query) for a Conduit, which pins its own Fee Manager’s id at create time.
Ongoing fees. onUpdate snapshots the current configId into the vehicle’s Cache as applicableConfigId, alongside the high water mark and timestamp. The next onOperations uses that snapshot, so a new rate only starts accruing after the vehicle’s next update.

Fee calculation formulas

Management fee formula

The management fee is annualized and prorated by time elapsed:

managementFeeAssets = currentTotalAssets * managementFeeBps * timeDelta / (10000 * 31536000)

Where timeDelta is the seconds elapsed since the last update and 31536000 is the number of seconds in a year (365 days).

Performance fee formula

The performance fee is applied to earnings above the high water mark:

earnings = max(0, currentTotalAssets - lastTotalAssets)
performanceFeeAssets = earnings * performanceFeeBps / 10000

The high water mark (lastTotalAssets) is refreshed when the vehicle calls onUpdate at the end of an operation, so you only pay performance fees on new gains.

Deposit and redeem fee formulas

Transactional fees are deducted from the gross amount:

feeAmount = amount * feeBps / 10000   // rounded down
netAmount = amount - feeAmount

For reverse calculations (determining gross amount from a desired net amount):

grossAmount = netAmount * 10000 / (10000 - feeBps)   // rounded up
feeAmount = grossAmount - netAmount

Configure fee recipients

Fee recipients define how collected fees are split among addresses. The sum of all recipient shares must equal 10,000 bps (100%).

FeeManager.FeeRecipient[] memory recipients = new FeeManager.FeeRecipient[](2);

// Targets must be sorted strictly ascending by address,
// and shares must sum to 10,000 bps

// 70% to the operator
recipients[0] = FeeManager.FeeRecipient({
    target: operatorAddress,
    shareBps: 7000
});

// 30% to the DAO treasury
recipients[1] = FeeManager.FeeRecipient({
    target: daoTreasuryAddress,
    shareBps: 3000
});

feeManager.setFeeRecipients(recipients);

// Coming soon

Updating recipients causes old recipients to lose access to any uncollected fees. Always call dispatchERC20 to distribute pending fees before changing recipients.

Collect accumulated fees

Performance and management fees accumulate as vehicle shares held by the Fee Manager. The Fee Manager never redeems those shares itself: a vehicle is an ERC20 share token, so you dispatch the shares to the recipients and each recipient redeems on its own schedule.

Monitor accumulated fees

Check the FeeManager’s share balance in the vehicle to see how much has been collected.

uint256 accumulatedShares = multiVehicle.balanceOf(address(feeManager));
uint256 sharePrice = multiVehicle.totalAssets() / multiVehicle.totalSupply();
uint256 feeValue = accumulatedShares * sharePrice;

// Coming soon

Dispatch the vehicle shares

Because the vehicle is itself an ERC20 share token, dispatch it like any other asset. Recipients receive vehicle shares, split by their shareBps.Requires: FEE_MANAGER_DISPATCH_ERC20 role.

feeManager.dispatchERC20(IERC20(address(multiVehicle)));
// Splits the Fee Manager's entire share balance across recipients;
// the last recipient absorbs the rounding remainder

// Coming soon

Dispatch collected assets

Transactional deposit and redeem fees reach the Fee Manager denominated in the payout asset rather than in shares. Dispatch each ERC20 balance the same way.Requires: FEE_MANAGER_DISPATCH_ERC20 role.

feeManager.dispatchERC20(IERC20(baseAsset));
// Distributes entire balance according to recipient shares

// Coming soon

dispatchERC20 reverts with ZeroValue when the Fee Manager holds none of the requested asset, so check the balance before dispatching.

View current configuration

Query the Fee Manager’s current state at any time.

// Get current fee configuration
(bytes32 configId, FeeManager.Fees memory currentFees) = feeManager.fees();

// Get maximum fee limits
FeeManager.Fees memory maxFees = feeManager.maxFees();

// Get current recipients
FeeManager.FeeRecipient[] memory recipients = feeManager.feeRecipients();

// Get fee cache for a specific vehicle (high water mark, last update, etc.)
FeeManager.Cache memory vehicleCache = feeManager.cache(address(vehicle));

// Coming soon

Preview fee impact

Use the view functions to simulate fee calculations without executing transactions.

// Preview performance + management fees that would be collected
uint256 feeSharesToMint = feeManager.previewOnOperations(
    totalSupply,
    totalAssets,
    sharesDecimals,
    assetDecimals
);

// Preview deposit or redeem fee deduction on a single asset
(Asset memory netAsset, Asset memory feeAsset) = feeManager.previewApplyTransactionalFees(
    configId,
    inputAsset,
    Mode.DEPOSIT
);

// Reverse calculation: find the gross asset needed for a target net asset
(Asset memory grossAsset, Asset memory reverseFeeAsset) = feeManager.reverseFees(
    configId,
    targetNetAsset,
    Mode.DEPOSIT
);

// Coming soon

Immutability and guardrails

Cannot change after deployment:

The FeeManager address (set during Multi-Vehicle or Conduit initialization; there is no setter)
The maxFees ceiling (set during FeeManager deployment)

Plan carefully: Choose maxFees conservatively. You can always charge less than the maximum, but you can never increase fees beyond it. For example, set maxFees.performanceFeeBps = 3000 (30%) even if you start at 2000 (20%) to allow future flexibility.

Getting started

How-to guides

Reference

The 4 fee types

Performance fee (on earnings)

Management fee (time-based)

Deposit fee (entry fee)

Redeem fee (exit fee)

When fees are applied

Fee recipients and distribution

Example configurations

Configuration

Prerequisites

Set fee percentages

Fee configuration IDs

Fee calculation formulas

Configure fee recipients

Collect accumulated fees

View current configuration

Preview fee impact

Immutability and guardrails

​The 4 fee types

​Performance fee (on earnings)

​Management fee (time-based)

​Deposit fee (entry fee)

​Redeem fee (exit fee)

​When fees are applied

​Fee recipients and distribution

​Example configurations

​Configuration

​Prerequisites

​Set fee percentages

​Fee configuration IDs

​Fee calculation formulas

​Configure fee recipients

​Collect accumulated fees

​View current configuration

​Preview fee impact

​Immutability and guardrails

The 4 fee types

Performance fee (on earnings)

Management fee (time-based)

Deposit fee (entry fee)

Redeem fee (exit fee)

When fees are applied

Fee recipients and distribution

Example configurations

Configuration

Prerequisites

Set fee percentages

Fee configuration IDs

Fee calculation formulas

Configure fee recipients

Collect accumulated fees

View current configuration

Preview fee impact

Immutability and guardrails