Hi,
The IANA AS Numbers registry has been updated to reflect the allocation of the following blocks to ARIN:
399261-400284 Assigned by ARIN 2020-11-02
400285-401308 Assigned by ARIN 2020-11-02
You can find the registry at:
https://www.iana.org/assignments/as-numbers/
The allocation was made in accordance with the Policy for Allocation of ASN Blocks to Regional Internet Registries:
https://www.icann.org/resources/pages/global-policy-asn-blocks-2010-09-21-en
Best Regards,
--
Selina Harrington
Lead IANA Services Specialist