What Is a VMFXX?

The Vanguard Federal Money Market Fund, or VMFXX, is an investment fund offered through Vanguard that invests in U.S. government securities.

As its main goal is to provide current income and preserve shareholders’ principal investments, the fund maintains a share price of $1. For this reason, it is considered one of the most conservative investment options offered by Vanguard.

How Does VMFXX Work?

The fund invests in very short-term investments of less than one year to maturity, if interest rates go up (or down), the yield will also go up (or down). Barring a financial crisis, there is little risk associated with this fund.

What’s the Average Yield of VMFXX?

The fund holds about $138 billion in assets. The amount of income that a shareholder may receive will be largely dependent on the current interest rate environment.


The Vanguard Federal Money Market Fund (VMFXX) and the Vanguard Prime Money Market Fund (VMMXX) are similar in purpose and investments.

The VMFXX invests in only short-term US government bonds and obligations. It is the safest possible thing one can invest it.

Similarly, the VMMXX invests mostly in U.S. Treasury bills and in short-term commercial paper. Either fund provides a safe place to invest cash, with minimal risk and a small return.