The Reliability Coordination Office (RCO) of the Western Electricity Coordinating Council (WECC) became operational in January 2009 in an on-going effort to monitor the reliable operations of the Western Interconnection in accordance with North American Electric Reliability Corporation (NERC) Reliability Standards. The West-wide System Model (WSM) is the nucleus of WECC's Energy Management System (EMS), created from merging three network models represented in the Common Information Model (CIM) format. Thus far, the RCO tools using the WSM have proven to be robust with high solution availability. The WECC Reliability Coordinator function (RC) is now in the initial stages of defining a data-sharing framework that would best address its future goals and the needs of its members. This paper proposes a framework that relies on CIM as a format to exchange systems modeling information among independent applications. The advantages, limitations, and challenges of using a CIM-based framework are highlighted in regard to the WECC RC's goal for model updating and data-sharing.