USDC on Arc mainnet exists both as the chain's base asset (ARC) and as an ERC-20 token (USDC_ARC_3Z5L), and both represent the same underlying balance. Fireblocks indexes and sends notifications only for the base asset, so we recommend using ARC for USDC on Arc mainnet for both incoming and outgoing transfers.

Incoming transfers

Fireblocks records incoming USDC transfers under ARC, not under USDC_ARC_3Z5L. On the ERC-20 side, the source of these transfers appears as External.

USDC_ARC_3Z5L does not receive incoming transfer notifications. Its balance only updates after a manual refresh.

Duplicate balances

If you add USDC_ARC_3Z5L as a token asset wallet, its balance duplicates funds already tracked under ARC. Fireblocks nullifies the rate on USDC_ARC_3Z5L, so the same funds are not valued twice, but the quantity still appears under both assets.

Important: This duplicate balance does not update automatically. We recommend not adding USDC_ARC_3Z5L to a vault account.