On the eve of a big deadline for states, the Obama administration decided to give them another month to decide whether to build their own online health insurance markets or leave exchange-building to the federal government.

States were supposed to inform the Department of Health and Human Services of their plans on Friday. Thursday night, HHS Secretary Kathleen Sebelius wrote governors to say they could have longer—until Dec. 14.

The extension is the second in as many weeks. Last week, Sebelius told states that an earlier deadline to submit detailed state plans on Friday would be extended. States that wish to build their own exchanges were asked to submit plans in December. Those that wish to collaborate with the federal government were asked to submit their plans by mid-February. Both of those deadlines remain unchanged.