The liquidation of CoOportunity Health, one of 23 non-profit health insurers created by the Affordable Care Act (ACA) has heightened concerns about the financial condition of the other CO-OP plans. This brief summarizes key data from CO-OPs’ third quarter 2014 National Association of Insurance Commissioners (NAIC) financial reports to state insurance regulators. We review CO-OP funding, enrollment, underwriting results, and rates. The data indicate that CO-OPs varied widely in terms of enrollment, pricing, and underwriting results. Many CO-OPs, including those with relatively high 2014 premium rates, had very little enrollment; others gained substantial enrollment, generally in conjunction with relatively low rates. That CO-OPs would face formidable actuarial, operational and financial challenges, with a significant likelihood that some would not become financially viable, has been recognized from the program’s initial planning stages. CoOportunity Health’s insolvency highlights those challenges and the potential consequences of rapid growth in conjunction with unfavorable claims experience, despite protection provided by the risk adjustment, reinsurance, and risk corridor programs. The experience highlights the need for close monitoring and oversight of CO-OP pricing and enrollment growth going forward.