The emergence of the cloud and advanced object-based storage services provides opportunities to support novel models for long term preservation of digital assets. Among the benefits of this approach is leveraging the cloud's inherent scalability and redundancy to dynamically adapt to evolving needs of digital preservation. PDS Cloud is an OAIS-based preservation-aware storage service employing multiple heterogeneous cloud providers. It materializes the logical concept of a preservation information-object into physical cloud storage objects. Preserved information can be interpreted by deploying virtual appliances in the compute cloud provisioned with cloud storage data objects together with their designated rendering software. PDS Cloud has a hierarchical data model supporting independent tenants whose assets are organized in multiple aggregations based on content and value. Continuous changes to data objects, life-cycle activities, virtual appliances and cloud providers are applied in a manner transparent to the client. PDS Cloud is being developed as an infrastructure component of the European Union ENSURE project, where it is used for preservation of medical and financial data. © 2013 IEEE.