Spaxx vs vmfxx SPAXX, also known as the Vanguard Federal Money Market Fund, invests exclusively in short-term U.S. government securities. This means that the fund is subject to minimal credit risk, as it invests in securities issued by the U.S. government or its agencies. The fund's yield has historically been lower than that of VMFXX due to its focus on low-risk investments. VMFXX, on the other hand, is the Fidelity Government Money Market Fund. This fund invests in a variety of short-term securities, including U.S. government securities, as well as securities issued by U.S. corporations and foreign governments. While this provides the potential for higher yields than SPAXX, it also introduces a higher level of credit risk. One key difference between the two funds is their minimum investment requirements. SPAXX has a minimum initial investment of $3,000, while VMFXX requires a minimum initial investment of $2,500. However, both funds offer lower minimums for subsequent investments. One key difference between the two funds is their minimum investment requirements. SPAXX has a minimum initial investment of $3,000, while VMFXX requires a minimum initial investment of $2,500. However, both funds offer lower minimums for subsequent investments. Another difference is their expense ratios. SPAXX has an expense ratio of 0.11%, while VMFXX has an expense ratio of 0.09%. This means that for every $10,000 invested in SPAXX, investors will pay $11 in annual expenses, while for every $10,000 invested in VMFXX, they will pay $9 in annual expenses. In terms of performance, both funds have historically performed well. However, SPAXX has generally had a lower yield than VMFXX due to its focus on low-risk investments. Over the past year, for example, SPAXX has had a yield of 0.01%, while VMFXX has had a yield of 0.09%.