Fees

OddsZero takes fees on every trade. Fees are never added to the collateral vault, so share backing is never diluted. This page covers every fee type, how it is computed, and where it goes.

Fee types

All fees are expressed in basis points (bps); 10000 bps = 100%.

Fee	Default (testnet)	Bound	Paid to	Snapshot
protocol_fee_bps	75 (0.75%) — fixed	only 75 accepted	Treasury	At market creation
creator_fee_bps	25 (0.25%) — fixed	only 25 accepted	Market creator	At market creation
dispute_bond_bps	100 (1.00%)	≤ 1000	Bond (returned/forfeited)	At market creation
maker_rebate_bps	2500 (25%)	≤ 10000	(discount, not a fee)	At market creation

Fees are now fixed. The protocol fee is locked at 0.75% (75 bps) and the creator fee at 0.25% (25 bps). Neither can be changed at market creation or via governance — the creator_fee_bps/protocol_fee_bps arguments supplied to the create-market entry points are ignored and always stored as these constants (FIXED_PROTOCOL_FEE_BPS, FIXED_CREATOR_FEE_BPS). This prevents an admin or creator from raising fees to rent-extract from traders.

Referral fees removed. Referral fees have been removed entirely. The referrals_enabled and referral_fee_bps fields still exist in the Governance object for backward compatibility but are unused — no referrer is ever paid. The referrer argument on create_market is accepted but ignored.

How a buy is split

For a buy of payment collateral, compute_buy first removes the fee portion from the set cost:

fee_bps   = protocol_fee_bps + creator_fee_bps
denom     = 10000 + fee_bps
set       = payment · 10000 / denom          // set cost that enters the vault
protocol_fee = set · protocol_fee_bps / 10000
creator_fee  = set · creator_fee_bps / 10000
shares    = shares_for_cost(pool, outcome, set)

The remaining payment − set − protocol_fee − creator_fee is routed to the treasury as a residual rounding remainder (the creator never receives dust that should belong to the protocol). The set portion is deposited into the collateral vault and priced by the AMM.

How a sell is split

c            = sell_return(pool, outcome, shares)   // gross return
protocol_fee = c · protocol_fee_bps / 10000
creator_fee  = c · creator_fee_bps / 10000
payout       = c − protocol_fee − creator_fee        // returned to seller

Maker rebate (close-out discount)

During the closing-only window (now >= closing_only_at), trades that net-reduce the outstanding float (close-outs) receive a discounted protocol fee:

effective_protocol_fee = protocol_fee · (10000 − maker_rebate_bps) / 10000

The default maker_rebate_bps is 2500 (25%), so the effective protocol fee on close-outs is 0.75% × (1 − 0.25) = 0.5625%. The creator fee is never discounted. The discount only reduces the protocol slice, so the vault backing invariant is untouched.

Where fees go

• Protocol fee → Treasury<T> (deposit_fee), withdrawable by admin.
• Creator fee → transferred directly to market.creator at trade time. It never touches the treasury.
• Bond (disputes) → held in a separate Balance<T> inside ResolutionState, settled on finalization (correct disputants repaid; frivolous bonds forfeited to treasury).

Changing fees

protocol_fee_bps, creator_fee_bps, dispute_bond_bps, and maker_rebate_bps live in the Governance shared object. The protocol and creator fees are fixed (only 75 and 25 are accepted respectively) and cannot be changed. dispute_bond_bps and maker_rebate_bps remain admin-adjustable via set_param or a DAO proposal. Because markets snapshot these values at creation, a global change only affects newly created markets.

See Governance and Treasury for the mechanics.