Buffalo's largest health insurance company is being sued for overcharging hospitals, schools and municipalities for 16 years to the tune of millions of dollars.

HealthNow New York is the parent company of BlueCross BlueShield of Western New York.

Paperwork filed in U.S. District Court says the company overcharged federal, state and local governments, as well as school districts.

The suit says the company didn't properly adhere to contractual requirements for services performed in hospitals, skilled nursing facilities, ambulatory surgery centers, and home health care providers.

Court paperwork alleges they overcharged private claims, not including Medicare or Medicaid, by $52 million in 2013 alone.

It goes on to say that even after discovering the issue in July 2013, HealthNow didn't make immediate changes and in 2014, it totaled $33 million in overpayments to hospitals alone.

The suit says all those costs got passed on to consumers, governments, and schools.

The suit says Alleghany Cattaraugus Schools and Orchard Park Schools were just a couple affected.

In a statement, BlueCross BlueShield says the lawsuit was originally filed under seal in 2016 but they just received the complaint but were aware of the issues raised when the U.S. attorney and New York state attorney general brought them up.

They go on to say they fully cooperated with the investigation.

They said their own investigation didn't find evidence of any significant cost to any state or federal health care program resulting from the HealthNow policies and mathematical formulas in place during the period described by the complaint.