Cramer: UnitedHealth move 'very damning' for ACA

UnitedHealth may leave Obamacare exchanges

UnitedHealth Group announced Thursday that it has pulled back on its marketing efforts for individual exchange products and would be evaluating whether the company can continue to serve public exchange markets, such as those set up by the Affordable Care Act, in 2017. 

While this news was "shocking" to CNBC's Jim Cramer, he said UnitedHealth won't be alone. 

"Every single one of the companies involved in this is going to have to do exactly what UNH did," he said. "This is very damning for [the Affordable Care Act]." 

UnitedHealth held more than 3 percent lower in morning trade after the health insurer cut its forecast for the year, citing low activity at public health care exchanges. Additionally, the health insurer's stock contributed the most to losses on the Dow Jones industrial average as of Thursday morning. 

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"I was staggered by this," Cramer said. "This is a political bombshell, not just a corporate bombshell."  

Centers for Medicare and Medicaid spokesman Ben Wakana's response made no reference to UnitedHealth's threat to pull out of public health exchanges in 2017. 

"As we've seen during the first two weeks of Open Enrollment, every day, tens of thousands more Americans turn to the Health Insurance Marketplace for health coverage and even more return to the marketplace for another year," Wakana said. "In fact, about nine out of 10 returning consumers will be able to choose from three or more insurers for 2016 coverage." 

Disclosure: Cramer's trust owned UnitedHealth Group's stock when this article was published.

— CNBC's Evelyn Cheng contributed to this report