Published: Jul 05, 2013 11:41 AM EDT

MIAMI (AP) - Will enough young, healthy adults purchase insurance under the Affordable Care Act or will they opt out and choose to pay a roughly $100 penalty?
    
Insurers are betting on the business of that group to offset the higher costs they will incur for older, sicker beneficiaries.
    
But experts warn that a lot of these so-called "young invincibles" could opt to pay the fine instead of spending hundreds or thousands of dollars each year on insurance premiums. If enough young adults avoid the new insurance marketplace, it could throw off the entire equilibrium of the Affordable Care Act.
    
Even though young healthy adults make up small subgroup of the insurance market, experts say it could be enough to throw the system's financing off-kilter.

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