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Marketplace fees

Fantums Reborn ships its own marketplace contract — Marketplace.sol — that handles secondary sales between users on Sonic. External marketplaces can still list our tokens (we ship EIP-2981 royalties so they earn the same 5%) but the in-house marketplace has its own fee structure with discounts for OG holders and sFUM holders.

The fee table​

RoleSell feeNotes
Default7.5%Standard. Applies to any seller not in another bucket.
OG seller5%If the token has isOG = true. Per-NFT discount.
sFUM holder1%If the seller holds ≥ N sFUM at sale time
Vanity-mode tokens3.75%Half the default. Trade-off for opting out of duels.
House Fantums—Can't be listed on the in-house marketplace; treasury-owned only

The lowest applicable fee wins. So an OG holder who also has ≥ N sFUM gets the 1% rate (sFUM holder), not 5% (OG). The OG perk is a floor, not an exclusive bucket.

Discount invariant​

This is a hard-coded contract invariant:

ogFeeBps <= feeBps      // always

Enforced in both Marketplace.setFee() and Marketplace.setOGFee(). The OG fee can never exceed the base fee. If the base fee ever ticks above 7.5%, the OG fee tracks down with it; never the other way around.

EIP-2981 royalty​

On top of the marketplace fee, every secondary sale (on our marketplace or external) pays an EIP-2981 royalty to a Treasury splitter:

SourceRoyaltyWhere it goes
In-house Marketplace5%Treasury splitter
External marketplace (PaintSwap, OpenSea-on-Sonic, etc.)5% (if they honour EIP-2981)Treasury splitter

The Treasury splitter routes royalties into:

  • 50% sFUM buyback + burn
  • 30% community treasury
  • 20% dev treasury (vested)

Royalty is independent of the marketplace fee. So an OG seller on our marketplace pays:

Buyer pays:      100 USDC
Royalty:           5 USDC  → Treasury (deflationary cycle)
Marketplace fee:   5 USDC  → House (operations)
Seller receives:  90 USDC

What the in-house marketplace adds​

FeatureDetail
Native sFUM paymentSellers can list in sFUM, USDC, or S
Bundle listingsList multiple Fantums in a single transaction (gas-cheap)
OG-only buy windowsSellers can flag a listing as OG-only for a set window
Royalty enforcementEIP-2981 enforced server-side; we cannot strip royalties even if a seller wants to
Floor sweep eligibilityTreasury can sweep the lowest-listed Fantum
Co-op resale (proposed)If a Fantum dies in a duel, its previous owner gets a "trophy royalty" share of the killer's next sale of that trophy

The co-op resale royalty is proposed but not shipped at launch. The idea: long-tail revenue for original owners of Fantums that get permadeathed.

Why not 0% fees​

We considered it. Two reasons we went with 1% sFUM-holder rate instead of 0%:

  1. Sybil resistance. A zero-fee tier invites wash trading. 1% is small enough to be a discount and large enough to make wash trading uneconomical.
  2. Revenue funds the buyback. The 2.5% of marketplace fees that route into the sFUM buyback only exists if there are fees to route. Zero-fee tiers break the deflation cycle.

1% is the floor.

Vanity-mode discount​

Tokens that have been permanently switched to Vanity mode (cannot duel, cannot be permadeathed — see Permadeath and revival) pay half the default fee on secondary sales. This is the trade-off you get for opting out of the arena: a quieter token with a cheaper resale tax.

The math: 3.75% marketplace fee instead of 7.5%. Royalty unchanged.

This discount does not stack with the OG or sFUM-holder discounts — Vanity-mode tokens fall into their own bucket. If a Vanity-mode token's owner also holds ≥ N sFUM, the sFUM holder rate (1%) wins because it's lower.

Float vs floor​

The marketplace UI surfaces two prices for every Fantum:

  • Asking price — what the seller wants
  • Floor — the lowest active listing for that Fantum's tier

The floor is computed on-chain from active listings. No off-chain indexer required. If our backend dies, the floor still ticks because the listings live on-chain.

See also​

Last updated: 2026-05-21