Financial services organizations regulated by SEC, CFTC, FINRA, IIROC, FCA, etc., are required to retain business-related communications in a Write-Once-Read-Many (WORM) or immutable state to ensure that they're non-erasable and non-modifiable for a specific retention interval. The immutable storage requirement is not limited to financial organizations. It also applies to industries such as healthcare, insurance, media, public safety, and legal services.
To address this requirement, immutable storage for Azure Blob storage is now generally available in all Azure public regions. Through configurable policies, users can keep Azure Blob storage data in an immutable state where blobs can be created and read, but not modified or deleted.
For more details on the feature, see the Microsoft Azure blog.