News reports said information from more than 700,000 Calpers members and retirees was taken.
The MOVEit software is widely-used by organisations around the world to share sensitive data.
Genworth Financial was harder hit, saying personal information of nearly 2.5 million to 2.7 million of its customers was breached.
"The personal information of a significant number of insurance policyholders or other customers of its life insurance businesses was unlawfully accessed," Genworth said.
The MOVEit hack has hit several state and federal agencies.
Persons:
PBI, Calpers, Genworth, Niket, Chris Sanders, Maju Samuel, Daniel Wallis
Organizations:
Genworth, PBI Research Services, U.S . Department of Energy, Washington DC, Thomson
Locations:
Calpers, Burlington , Massachusetts, Russia, Bengaluru, Washington