Yale University workers who sued the school over their retirement plan want a federal judge to certify their case as a class action covering more than 14,000 people.

The workers say Yale’s retirement plan carried excessive fees and offered poorly performing investment options. Their Jan. 15 motion comes nine months after a federal judge in Connecticut largely denied the school’s attempt to have the case dismissed.

At least 20 prominent colleges have been sued over their retirement plans since 2016. Cases against New York University, Emory, Duke, Vanderbilt, Massachusetts Institute of Technology, and Columbia University have been certified as class actions.

Rulings in these cases have been mixed. Only the NYU case has gone to trial, which resulted in a 2017 victory for the school. Five federal appeals courts have been asked to weigh in, but none has issued a ruling on the merits of these cases.

The case against Yale is pending before Judge Alvin W. Thompson of the U.S. District Court for the District of Connecticut.

Schlichter Bogard & Denton LLP and Cohen & Wolf PC represent the Yale employees. Mayer Brown LLP represents Yale.

The case is Vellali v. Yale Univ., D. Conn., No. 3:16-cv-01345-AWT, motion for class certification 1/15/19.