California state officials said on Tuesday they were ordering a major Christian group to stop offering an alternative to health insurance, joining several states scrutinizing these cost-sharing programs that provide limited coverage.

The plans, which have become increasingly popular, rely on pooling members’ contributions to cover their medical expenses, but they are not required to meet standards for traditional insurance plans.

The state’s insurance regulators accused Trinity HealthShare, which runs ministry plans, and Aliera, which sells them, of misleading consumers and offering products tantamount to health insurance policies without state approval.

The state estimated that up to 11,000 residents might belong to plans being offered by Aliera and Trinity.