Federal milk marketing order pooling issues have been frequent topics of discussion, especially since federal order reform was implemented in January 2000. Particularly controversial are depooling and distant pooling, both of which affect federal order producer prices. Numerous questions have been raised related to what is pooling, what producers are eligible to share in federal order pools, what is a pool milk plant, how do regulated manufacturing milk plants decide to pool or depool, and how does pooling affect producer pay prices, in particular the producer price differential (PPD) and the uniform producer price. Two recent events focused increased attention on pooling issues. In April 2004, the PPD in many milk marketing orders was a record negative value — ($4.11) per hundredweight in the Upper Midwest order. While the large negative difference between the April Class I and Class III prices ($15.44 and $19.66 per hundredweight, respectively) was the primary cause of negative PPDs, they were made even larger because many manufacturing plants and dairy cooperatives chose to depool, that is, disassociate milk from orders. The Upper Midwest market administrator estimated that 1.6 billion pounds of milk was depooled in April 2004.2 Depooling resulted in April 2004 Class III utilization of only 11 million pounds (1.8 percent of total use) compared to 1.4 billion pounds (76.8 percent) in April 2003.