"The President's administrative fix compounds the risk of insufficient enrollments in the ACA's health insurance plans to provide insurers with sufficient premiums to cover their costs," Moody's said. "Additionally, according to the Department of Health and Human Services, enrollment on the exchanges thus far is much lower than government projections, a credit negative for participating health insurers."

Moody's named some of the carriers that it thinks will likely take a hit as the administration tries to correct course.

"For insurance companies that have invested heavily in the insurance exchanges in the hopes of obtaining increased individual enrollment, such as WellPoint, Inc. (Baa2 stable) and Health Net, Inc. (Ba3, positive), these results are a serious disappointment. Besides the low return in membership from their administrative expense investment, the exposure to adverse selection is likely to negatively affect earnings in 2014," Moody's said.

Still, the situation could right itself, Moody's suggests.

"Since the open enrollment period does not end until March [31], the enrollment figures could improve. However, given the technical problems on the health exchanges' websites, the President's administrative fix that allows insurers to reinstate recently cancelled policies, as well as the possibility of further legislative or administrative action to either delay the individual mandate or extend the open enrollment period, the prospect for meeting the Congressional Budget Office's projected enrollment figure of 7 million by the end of March is unlikely."