Moves custodial funds from the authenticated marketplace to one of its sub-merchants. Only the MARKETPLACE → SUB_MERCHANT direction is allowed: originId MUST be the authenticated marketplace and destinationId MUST be a sub-merchant it owns. The amount is debited from the marketplace custodial wallet and credited to the sub-merchant custodial wallet on Base.

Privy-custodial origins settle synchronously (CONFIRMED). Bridge-custodial origins are submitted asynchronously (PROCESSING) and confirmed later via webhook. Provide an idempotencyKey to safely retry without double-spending.