How can one compare the yield of a municipal money fund with the yield of a municipal bond?

Question

Let's consider the following municipal money fund and the following municipal bond:

1. The Schwab Municipal Money Fund (Investor Shares) (SWTXX) discloses a 7-day yield (with waivers) as of 02/28/2023 of 3.04% (tax-free).
2. I see in Charles Schwab a municipal bond with a yield-to-maturity of 2.81% (tax-free).

The two yields 3.17% and 2.81% can't be compared, since e.g. the yield-to-maturity assumes that:

The owner reinvests all interest payments rather than spending them, to gain the benefit of compounded returns.

whereas the yields 3.17% doesn't assume that.

How one can compare the yield of a municipal money fund with the yield of a municipal bond?

Answer 1

You can't directly compare fund yields to bond yields because they don't measure the same things.

Fund yield measures the average interest income paid over the last 7 days. In your example it was 3.04% (See the definition: The 7-Day Yield is the average income paid out over the previous seven days assuming interest income is not reinvested).

Bond yield measures the interest payments that you'd be collecting until the bond's maturity (i.e.: the interest you'd be earning if you hold the bond until the borrower repays the debt).

The difference is that the bonds' yields don't change once you buy the bond. It's a contract, the borrower pays the fixed interest quoted, and that's not going to change.

Funds' yields change all the time, because they hold various different bonds, redeeming and repurchasing them all the time.

These are very different things, and are not comparable unless you're buying very short term bonds (e.g.: weekly bonds), because then the fluctuations of the bond yields come close to the fluctuations of the fund yields. But if you're buying into a fund and are comparing it to a long term bond - then it's meaningless because by the time the bond matures interests will have gone up and down multiple times, affecting the fund yields over the same period significantly.

Another difference, of course, is that the bond matures. Fund (for most parts) never does. There are some funds with maturity dates, but even then they distribute NAV, while when bond matures you get the nominal value (the loan amount). So with funds you are also more likely to have capital gains/losses than with bonds (that you hold to maturity).