The largest money market mutual funds most used by DC plans

U.S. defined contribution assets, in millions, as of June 30, 2018.
1Vanguard Federal Money Market$17,732
2Fidelity Gov't Money Market$12,082
3Fidelity Gov't Cash Reserves$9,670
4Wells Fargo Gov't Money Market$7,767
5Fidelity MM Gov't Portfolio$5,526
6Vanguard Prime Money Market-Adm.$4,590
7American Funds U.S. Gov't MM$3,896
8Federated Gov't Obligations$3,316
9Vanguard Treasury Money Market$2,969
10Federated Treasury Obligations$1,612