Effective July 1, 2016 Fidelity will reduce expenses on 16 index mutual funds (formally Spartan funds) and 11 sector index ETFs.
Among the changes, the ER for the 500 Index fund (premium) and Total Market Index fund (premium) will drop from 0.05% to 0.045%. Their "institutional premium" class offered in some 401k plans will drop to 0.015%.
The ER for U.S. Bond Index Fund (premium) will drop from 0.07% to 0.05%. The "institutional premium" class will drop to 0.03%.