NEW YORK (Reuters) - The number of Americans who signed up for 2019 insurance plans created by the Affordable Care Act, often called Obamacare, fell by about 4 percent to 8.5 million people from 2018, the U.S. government said on Wednesday.

FILE PHOTO: A sign on an insurance store advertises Obamacare in San Ysidro, San Diego, California, U.S., October 26, 2017. REUTERS/Mike Blake

Enrollment had been running about 10 percent lower but picked up during the past week, reflecting a typical trend of last-minute shopping, the Centers for Medicare and Medicaid Services (CMS) Administrator Seema Verma said in a call with reporters.

Verma said the decrease was due to increased employment, which typically means more people had employer-based health insurance, and that about 100,000 people with Obamacare insurance in Virginia became eligible for the expanded Medicaid program there.

Wall Street analysts had expected a decline in the federal Obamacare marketplace and had cited competing insurance options, a cut in advertising spending from the previous administration to promote the program and the removal of the law’s individual mandate that had required people to have health insurance or pay a fine.

Verma said those changes had not had an impact on enrollment. “We see no correlation between what we are seeing on advertising and effectuated enrollment,” she said.

As of Dec. 15 at midnight EST, 8,454,882 people had signed up for plans, she said. But those numbers are not final. The marketplace was open for three additional hours and continues to try to reach 200,000 people who were unable to complete their enrollment by the deadline, she said. The agency runs enrollment through the online marketplace, HealthCare.gov, for 39 states.

Enrollment closed just one day after a ruling from a federal judge in Texas that the Affordable Care Act (ACA) was unconstitutional, setting off a cascade of worries about the future of these plans and other key tenets of the law, such as the expansion of the Medicaid program for the poor.

But there is no immediate impact on the plans in 2019. Legal experts and Wall Street analysts have said that an appeal will stretch into next year and that if the ruling were to be upheld, it would likely move to another appeal at the Supreme Court in 2020.

The figures reported on Wednesday do not include data for the other 11 states plus Washington D.C, which run their own individual insurance marketplaces and set their own enrollment closing dates. California, for instance, closes enrollment on Jan. 15, 2019.

Those 11 states make up about 25 percent of enrollment, which was about 11.8 million across the country at the beginning of 2018, a decline of about 400,000 people from 2017.

Private insurers including Centene Corp. CNC.N, Molina Healthcare MOH.N and Anthem Inc ANTM.N, offer individual Obamacare plans, though it is a small portion of their overall business.

The Texas court decision late on Friday pushed down shares of those companies as investors took account of the new risk to insurers who provide individual insurance and Medicaid coverage.

The ACA is widely considered to be the signature domestic achievement of former President Barack Obama.

Republicans in Congress failed to overturn it through legislation, despite being pushed to do so by U.S. President Donald Trump. But the administration has been able to take away some of its provisions and introduced new rules to bolster competing plans. It has also cut advertising and services to promote the Obamacare plans.

The new plans are attractive to individuals who do not qualify for income-based government subsidies that make Obamacare plans more affordable, Leerink analyst Ana Gupte said in a recent note.