The Trump administration proposed new rules on Wednesday to stabilize health insurance markets roiled by efforts to repeal the ACA, by big increases in premiums and by the exodus of major insurers. The move came a day after Humana announced that, starting next year, it would completely withdraw from the public marketplaces created under the ACA. The proposed rules, backed by insurance companies, would tighten certain enrollment procedures and cut the health law’s open enrollment period in half, in hopes that a smaller but healthier consumer base will put the marketplaces on sounder financial footing and attract more insurance companies in states with limited choices.

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