Fees

How Vision’s fee structure works — 0.05% on profits only

0.05% on profits only. Losers pay nothing. This is the closest thing to justice a financial protocol can offer. The tax falls only on those who have something to be taxed. The rest are left alone with their losses, which is kindness of a sort. Five basis points — barely a touch, the smallest tax mathematics permits before disappearing entirely.

Fee Summary

What	Amount
Fee rate	0.05% on profits only
Losers pay	Nothing
Min stake	0.1 USDC per tick

Example: You win 20 USDC → fee is 0.01 USDC → you receive 19.99 USDC.

Fee Constants

uint256 public constant PROTOCOL_FEE_BPS = 5;       // 0.05% in basis points
uint256 public constant BPS_DENOMINATOR = 10000;     // Basis point denominator

Parameter	Value
Fee rate	0.05% (5 basis points)
Denominator	10,000
Applied to	Profits only (winnings above your deposit)
Losers pay	Nothing

Fee Formula

When a player claims rewards and their new balance exceeds their old balance, the protocol takes its share. The arithmetic is clean. Five basis points, applied to profits, never to principal:

winnings = newBalance - oldBalance
fee = (winnings * 5) / 10000
payout = winnings - fee

Worked Example

A player has a current balance of 100 USDC and wins 20 USDC across several ticks. Here is what the protocol keeps and what the player receives — the small toll exacted on fortune:

oldBalance = 100,000,000  (100 USDC, 6 decimals)
newBalance = 120,000,000  (120 USDC)

winnings   = 120,000,000 - 100,000,000 = 20,000,000  (20 USDC)
fee        = (20,000,000 * 5) / 10,000 = 10,000       (0.01 USDC)
payout     = 20,000,000 - 10,000 = 19,990,000          (19.99 USDC)

The player receives 19.99 USDC in profit. The protocol accumulates 0.01 USDC in fees.

Fees are calculated in USDC with 6 decimal places. The integer division means sub-cent amounts are truncated (rounded down), slightly favoring the player. Even the rounding errors are merciful.

When Fees Apply

Fees appear at two moments: when you claim your winnings, and when you leave. Both are moments of accounting — the protocol tallies what you earned and takes its fraction. Only its fraction. Never more.

On Claim

When a player calls claimRewards, the fee is computed on the difference between the old and new balance:

if (newBalance > oldBalance) {
    uint256 winnings = newBalance - oldBalance;
    uint256 fee = (winnings * PROTOCOL_FEE_BPS) / BPS_DENOMINATOR;
    accumulatedFees += fee;
    uint256 payout = winnings - fee;
    USDC.safeTransfer(msg.sender, payout);
}

If newBalance <= oldBalance, the player lost money over the claim period. No fee is charged, and no USDC is transferred.

On Withdrawal

When a player calls withdraw to exit a batch, the fee is computed on total profit over the lifetime of the position:

uint256 totalDeposited = position.totalDeposited;
uint256 profit = finalBalance > totalDeposited ? finalBalance - totalDeposited : 0;
uint256 fee = (profit * PROTOCOL_FEE_BPS) / BPS_DENOMINATOR;
uint256 payout = finalBalance - fee;

This means the fee on withdrawal considers the entire history, not just the latest claim window.

Withdrawal Example

A player deposited 500 USDC total over time. Their final balance is 650 USDC:

totalDeposited = 500,000,000  (500 USDC)
finalBalance   = 650,000,000  (650 USDC)

profit  = 650,000,000 - 500,000,000 = 150,000,000  (150 USDC)
fee     = (150,000,000 * 5) / 10,000 = 75,000        (0.075 USDC)
payout  = 650,000,000 - 75,000 = 649,925,000          (649.925 USDC)

Losers Pay Nothing

If a player’s balance decreases over a tick (or over their entire position lifetime), no fee is charged. The fee only applies to positive winnings. Loss is its own punishment. The protocol does not add to it.

• If you deposit 100 USDC and your balance drops to 80 USDC, you withdraw 80 USDC with no fee.
• If you deposit 100 USDC, it goes to 50 USDC, then recovers to 110 USDC, you only pay fees on the 10 USDC profit when you claim or withdraw.

Fees are never applied to your deposited principal, only to gains above it. The protocol only charges for the privilege of being right. Being wrong is free.

Minimum Stake

To join a batch, the player’s stakePerTick must be at least MIN_STAKE_PER_TICK. Ten cents. The price of admission to a prediction market. The price of having an opinion and backing it with something other than words:

uint256 public constant MIN_STAKE_PER_TICK = 1e5; // 0.1 USDC (6 decimals)

Parameter	Value
Minimum stake per tick	100,000 (0.1 USDC)
USDC decimals	6
Minimum deposit	Must be >= stakePerTick

This minimum prevents dust attacks and ensures each player has a meaningful stake in the game.

If stakePerTick is less than MIN_STAKE_PER_TICK, the joinBatch call reverts with StakeBelowMinimum. If the initial deposit is less than stakePerTick, it reverts with InsufficientDeposit.

Fee Collection

Accumulated fees are held in the Vision contract until the designated feeCollector address calls collectFees. The fees sit there, accruing, waiting — the protocol’s quiet tax on the perpetual optimism of its participants:

function collectFees() external {
    if (msg.sender != feeCollector) revert Unauthorized();

    uint256 fees = accumulatedFees;
    accumulatedFees = 0;

    USDC.safeTransfer(feeCollector, fees);
}

• Only the feeCollector (set at contract deployment) can withdraw accumulated fees.
• Fees are transferred as a lump sum, resetting the accumulatedFees counter to zero.

Solvency Check

Every claim and withdrawal includes a solvency check to ensure the contract can cover the payout plus any accumulated fees:

if (USDC.balanceOf(address(this)) < payout + accumulatedFees) revert InsolventPayout();

This prevents a scenario where payouts exceed the contract’s actual USDC holdings. The contract will not promise what it cannot deliver. In this it is more honest than most institutions.