The second-year start of Obamacare enrollment will be pushed back by one month to give health insurers more time to prepare new plans and rates, an official with the U.S. Department of Health and Human Services said.

That enrollment period, previously scheduled to begin Oct. 15, 2014, will now start Nov. 15, said the official who asked not to be identified because the decision isn’t public. The change is important to insurers that need more time to evaluate the first year of the government-run marketplaces, set up last month as part of the Patient Protection and Affordable Care Act.

Young and healthy people who are necessary to balance the financial risk posed by older Americans aren’t likely to sign up in large numbers until March, said Jonathan Gruber, an economist at the Massachusetts Institute of Technology who helped design the 2010 health law. Giving insurers extra time to set second-year rates may result in lower premiums.