Nearly 100,000 public charter school teachers are in danger of losing already earned pension benefits if a proposed IRS rule goes into effect this June. The public comment period on the regulation ends today, with no word from the agency regarding its decision.

The IRS selected a basket of public employee categories (including zoo keepers) to stop designating as government groups, meaning they would lose eligibility for state pensions. This regulation would force states to yank charter school teachers from state retirement plans and retroactively pull matching funds the state has already contributed to their accounts. Every single state that authorizes charter schools currently either requires or permits charter schools to participate in the state’s retirement system.