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Bond funds and bond ETFs
· Asset or instrument
Fact, law or dataA rule, statute, definition or measured number.
Bond funds pool investors' money to hold hundreds or thousands of bonds, sold as mutual funds or exchange-traded funds (ETFs).
See it on the Money & Finance map →How it works
A mutual fund is priced once a day at net asset value; an ETF trades all day on an exchange. Types include Treasury, 'aggregate' (a broad US mix of Treasuries, mortgage bonds and corporates), corporate, high-yield, muni, TIPS and short-term funds. Unlike a single bond, most funds never mature: they keep replacing bonds, so their duration stays roughly constant and no fixed date returns your principal. Broad index bond ETFs charge as little as 0.03% a year. Most pay income monthly.
Why it matters
They are how most people, and most 401(k)s, own bonds. 2022 showed their risk: the main US bond index fell about 13%, its worst year on record.
Think of it like
Like owning a slice of a lease portfolio that is constantly re-leasing: no single expiration date, and income drifts toward current market rates.
Facts, rules and data
Fund prospectuses and fact sheets list holdings, duration, yield and fees. Broad bond index ETFs (aggregate or Treasury) are the common low-cost route for individual investors; 'defined maturity' ETFs mature like single bonds.
Debates and risks
Whether individual bonds held to maturity are truly safer than funds is debated; the difference is mostly in how losses show up, not whether they occur.
Connections (2)
▸Duration: how sensitive a bond is to rates sets the rate risk of Bond funds and bond ETFsFact, law or data
The connection
A bond fund's average duration tells how much its share price drops per 1-point rise in rates. Because funds keep buying new bonds, their duration stays roughly fixed and losses are not recovered on a set date; instead higher yields on new bonds gradually rebuild returns, roughly over a period equal to the duration.
When and why
Fund fact sheets list 'average effective duration'. Short-term funds sit near 2 years, broad aggregate funds near 6, long Treasury funds near 16.
How we know
2022 returns lined up with duration: short-term Treasury funds lost about 4%, aggregate funds about 13% and long Treasury funds about 30%.
Debates and risks
The 'break even after one duration' rule assumes one rate change and steady yields after; real paths vary, so recovery times differ.
▸Bond funds and bond ETFs make up a fast-growing share of Exchange-traded funds (ETFs)Fact, law or data
The connection
Individual bonds trade rarely and over the counter, so buying many is costly. A bond ETF bundles hundreds or thousands into one share that trades all day on an exchange, at fees as low as a few hundredths of a percent. Many investors now get their bond exposure this way.
When and why
iShares launched the first US bond ETFs in July 2002; the category grew rapidly after 2008 and again after 2020.
How we know
Fund filings and industry flow data show the growth; in 2020 the Fed itself bought corporate bond ETFs to calm credit markets.
Debates and risks
In March 2020 some bond ETFs traded well below their holdings' stated value; whether that showed fragility or simply more honest prices is debated.