WRS Trust Funds - Core and Variable What are the differences between the Core and the Variable Trust Funds? Is Variable Fund participation still a good choice for members – how does it affect retirement benefits? This webcast provides the answers to these and other frequently- asked questions about the Wisconsin Retirement System Trust Funds. It also provides information about the State of Wisconsin Investment Board’s management of trust fund investments, how effective rates and annuity adjustment are calculated, what it means to have a Variable “excess” or “deficiency” and how to cancel and/or elect Variable participation. (Javascript is required to view Mediasite content)