The largest money market mutual funds most used by DC plans

U.S. defined contribution assets, in millions, as of June 30, 2017.
1Vanguard Federal Money Market$16,211
2Fidelity Gov't Cash Reserves$9,441
3Fidelity MM Trust Ret. Gov't$8,764
4Fidelity MM Gov't Portfolio$5,994
5Wells Fargo Gov't Money Market$5,699
6Vanguard Prime Money Market-Adm.$4,532
7American Funds U.S. Gov't$4,307
8Federated Gov't Obligations$3,408
9Vanguard Treasury Money Market$2,691
10Schwab Money Market$2,413