Clearing & Settlement

NCRB trades settle on-chain via an atomic swap — payment and token delivery happen simultaneously in a single blockchain transaction. Each supported registry has its own process for tokenization (how a certificate enters NCRB) and off-chain retirement notification (what happens at the registry when a token is retired on-chain).

On-Chain Settlement — Atomic Swap

When a buyer confirms a purchase, the RWAMarketplace.buy() smart contract function executes all of the following atomically. If any step fails, the entire transaction reverts and nothing changes:

Buyer's USDC payment
        │
        ├──► Seller receives their share
        │    (listed price minus platform fee)
        │
        ├──► NCRB treasury receives platform fee (2.5%)
        │
        ├──► Aggregator receives royalty (if routed via an aggregator)
        │
        └──► RWA tokens released from escrow → buyer's wallet

There is no waiting period, no manual handover from the seller, and no counterparty risk. Settlement is instant — one block confirmation (~2 seconds on Avalanche).

Listing Escrow

When a seller creates a listing, the RWA tokens are transferred immediately into the RWAMarketplace contract. They remain locked in escrow until either the listing is purchased (tokens go to buyer) or the seller cancels (tokens returned). This guarantees that any token shown as available genuinely exists and cannot be spent elsewhere during the listing.

Comparison with Traditional Models

Traditional model	NCRB atomic swap
Buyer pays → waits → seller manually sends asset	Payment and delivery in one transaction
Risk of non-delivery after payment	Impossible — contract enforces delivery atomically
Off-chain reconciliation or trust required	Fully on-chain, no counterparty risk
Settlement delay (hours to days)	Instant (one block confirmation)

Tokenization Lifecycle (all registries)

Before a credit can be traded, it must be tokenized. This process is the same regardless of registry:

Registry issues certificate (serial number)
        │
        ▼
Registry partner imports serial into NCRB
(Registry Import tab — metadata auto-filled from registry API)
        │
        ▼
Registry partner submits certificate on-chain
(IPFS metadata pinned; RWAToken created, pending governance)
        │
        ▼
MultiSig governance votes (3-of-5, 7-day window)
        │
        ▼
Certificate approved → tokens distributed to recipients
        │
        ▼
Tokens listed on marketplace → available for purchase
        │
        ▼
Buyer purchases → atomic swap settles in one transaction
        │
        ▼
Buyer retires token on-chain → registry partner retires off-chain

Clearing & Settlement by Registry

While on-chain settlement is identical across all registries, each registry differs in how tokens are imported and how off-chain retirement is handled.

Registry	Issuer	Serial Format	Import Method	On-Chain Settlement	Off-Chain Retirement	Status
Verra VCS	Verra (Washington D.C.)	Numeric — e.g. `4017`	Auto-import via Verra API	Atomic swap — instant	Registry partner manually retires the serial in the Verra Registry	✅ Live
Verra VPP (Plastic)	Verra	Numeric — PWRP pathway	Auto-import via Verra API	Atomic swap — instant	Registry partner retires in Verra Registry (PWRP project detail)	✅ Live
Gold Standard	Gold Standard Foundation (Geneva)	`GS` + number — e.g. `GS11892`	Auto-import via Gold Standard API	Atomic swap — instant	Registry partner retires via Gold Standard Registry	✅ Live
ACR (American Carbon Registry)	Winrock International	`ACR` + number — e.g. `ACR123`	Manual certificate submission	Atomic swap — instant	Registry partner retires via ACR APX system	🔜 Planned
CAR (Climate Action Reserve)	Climate Action Reserve	`CAR` + number — e.g. `CAR1234`	Manual certificate submission	Atomic swap — instant	Registry partner retires via CAR APX system	🔜 Planned
CDM (Clean Dev. Mechanism)	UNFCCC	Varies by project	Manual certificate submission	Atomic swap — instant	Retirement via UNFCCC CDM registry	🔜 Planned
Isometric	Isometric (San Francisco)	`prj_` prefix	Manual certificate submission	Atomic swap — instant	Retirement via Isometric Registry	🔜 Planned

Key Distinctions: Clearing vs Settlement

Clearing on NCRB is fully automated and on-chain. The moment a buy() transaction is confirmed on the blockchain, the trade is cleared — both parties have received what they are owed, and the event is permanently recorded.

Settlement at the underlying registry level is currently a manual step performed by the registry partner. When a buyer retires tokens on NCRB, the registry partner is responsible for marking the corresponding serial number as retired in their native registry to prevent double-counting.

NCRB records the on-chain retirement event (wallet address, serial number, timestamp, standard claimed) as the primary audit trail. The off-chain registry retirement provides the complementary record for compliance and ESG reporting purposes.

Future Roadmap

NCRB plans to automate the off-chain retirement step via direct registry API integration where registries support programmatic retirement. When automated, the on-chain retirement event will trigger an API call to the relevant registry, completing the full clearing cycle without manual action by the registry partner.

Verra and Gold Standard both have partial APIs; neither currently exposes a public programmatic retirement endpoint. NCRB will integrate these as they become available.

On-Chain Settlement — Atomic Swap​

Listing Escrow​

Comparison with Traditional Models​

Tokenization Lifecycle (all registries)​

Clearing & Settlement by Registry​

Key Distinctions: Clearing vs Settlement​

Future Roadmap​