Preferred Provider Organizations (PPOs) are growing at the expense of Health Maintenance Organizations (HMOs). An estimated 113 million eligible employees were served by respondent medical/surgical and full-service PPOs in 2001, up from 111 million in 2000. The number of operating PPOs declined to 925 in 2001 from 988 the previous year. PPOs are similar to traditional health insurance because they provide a member with the freedom to choose a physician or other health care provider. In a PPO, the member is encouraged, through financial incentives, to use participating health care providers which have contracted with the PPO to provide services at favorable rates. In the event a member chooses not to use a participating provider, the member may be required to pay a greater portion of the provider's fees. Many PPOs have matured into originations that implement sophisticated care management techniques and monitor their members' health. Knowledge Source's PPO Market Overview identifies the market trends and statistics as well as the major market participants.