Holding Health Insurers Harmless Act This bill exempts health insurers and group health plan sponsors from penalties for offering coverage or plans that fail to comply with the Patient Protection and Affordable Care Act and the Health Care and Education Reconciliation Act of 2010. Coverage and plans must continue to comply with (1) the prohibition on excluding preexisting conditions from coverage, and (2) the requirement for coverage of dependent children to be available until the dependent turns 26 years old.