How Circle StableFX Trades and Settles Stablecoin FX on Arc

Circle StableFX separates pricing from settlement: an approved institution requests a quote for a stablecoin currency trade, then the token exchange settles on Arc. Circle described the service as providing 24/7 cross-currency settlement when Arc’s public mainnet launched on September 16, 2026.517

Who can use StableFX?

StableFX is a permissioned institutional service, not an open retail exchange. Reporting describes access for incorporated businesses that pass Circle’s compliance screening, including payment companies, financial institutions and corporate treasury users.6 A participant also needs access to StableFX and a wallet connected to Arc; Circle’s wallet documentation includes a mainnet configuration.47

How do quotes and settlement work?

The trading institution requests a price for a currency pair and amount. StableFX uses an offchain request-for-quote (RFQ) process to obtain pricing from liquidity providers; the institution selects an executable quote before the parties fund their respective obligations.617

Settlement is atomic payment-versus-payment (PvP): once the required tokens are delivered for the trade, the exchange of the two stablecoin legs completes together rather than leaving one party having paid while the other has not delivered. This reduces the risk associated with a gap between the two transfers, but it does not eliminate the need for both sides to fund the trade or make liquidity available.11217

Which currencies are available?

Circle’s technical guide identifies USDC and EURC as examples of fiat-backed currencies for StableFX conversion.17 In its mainnet announcement, Circle listed these tokens as active or onboarding to StableFX: USDC, EURC, AUDD, AUDF, BRLA, CADD, CHFAU, EURAU, GBPA, JPYC, KRW1, MXNB, QCAD, SEKAU, TRYB, wARS, wBRL, wCLP, wCOP, wMXN, wPEN and ZARU.5

That combined list is not a live trading-pair list. It does not show which pairs an institution can quote now, whether a particular token has finished onboarding, or when additional pairs will become available.5 A token being live on Arc does not, by itself, establish that a corresponding StableFX pair is available; for example, QCAD’s issuer says QCAD is live on Arc, while Circle places it in the broader “active or onboarding” StableFX list.75

What does Arc add—and where does StableFX stop?

Arc is the blockchain on which the token exchange settles. Its mainnet provides USDC-denominated transaction fees and what Circle describes as deterministic sub-second finality, allowing onchain settlement outside conventional banking hours.25 Always-on settlement does not guarantee that a desired quote or sufficient liquidity will be available at every moment.

The completed FX trade delivers stablecoins, not fiat cash. To put the proceeds into a bank account or pay a recipient through a local payment system, an institution still needs appropriate redemption, banking and payout arrangements. StableFX’s onchain settlement alone does not establish those services for every token or destination.517