Bridge Builder Municipal Bond Fund

Bridge Builder Trust · Series S000050632 · 1 share classes

Bond fund · 98% debt· rate + credit risk filed
One fund, 1 share classes:BBMUX
$20.79B NAV
5,793 positions · as of 2026-06-30 · filed 2026-08-26
data updated 2026-09-08

Fund profile

As filed in the prospectus · 2025 Q4

The investment objective of the Bridge Builder Municipal Bond Fund (the Fund or the Municipal Bond Fund) is to provide current income exempt from federal tax,

Strategy · summarised

The fund invests at least 80% of assets in municipal securities whose interest is exempt from federal income tax, with day-to-day management delegated to four sub-advisers—Baird, BlackRock, FIAM, and MacKay Shields—each employing distinct strategies ranging from duration-neutral relative-value approaches to top-down macro combined with bottom-up credit research. The fund may hold municipal securities rated below investment grade, also known as junk bonds, or unrated securities that a sub-adviser believes are of comparable quality to investment-grade instruments. Because returns depend on the security selections and sector positioning decisions made by the sub-advisers, performance will diverge from any single benchmark.

Expenses
0.12%one share class
Share classGrossNet
BBMUX0.38%0.12%

Net is what a holder pays after the adviser's contractual waiver; gross is before it. A waiver can expire.

Portfolio turnover 37.00% · as of 2025 Q4

Allocation

Asset groups · long / short shown separately, never netted · 2026 Q2

98.46%
of net assets
Bonds96.24%
Securitized1.51%
Cash & short-term1.04%
Derivatives-0.34%

The outer band is exposure held short — written against the portfolio rather than part of it, which is why it sits outside the ring and why the two are never netted into one figure.

Derivatives are shown at market value, not notional exposure.

Latest quarter

What changed since the fund's previous filing

2026Q2 vs 2026Q1: 361 new292 exited

Largest new: F/C US LONG BOND(CBT) SEP26, MAIN STREET ENERGY 5% 10/01/33, BLACK BELT ENERGY 5% 11/01/36, UNIV OF TEXAS TX V/R 08/01/56, ENERGY S E AL A CO 5% 11/01/33, BLACK BELT ENERGY 5% 01/01/34, PEFA INC IA GAS PR 5% 04/01/35, NEW YORK NY V/R 04/01/42

Largest exited: F/C US LONG BOND(CBT) JUN26, TARRANT CNTY TX C V/R 11/15/63, CUMBERLAND CNTY N V/R 12/01/27, MASSACHUSETTS ST V/R 07/01/61, TRIBOROUGH NY BRID 5% 02/01/28, HARRIS CNTY TX CUL 5% 12/01/29, NEW YORK ST DORM A 4% 03/15/42, MASSACHUSETTS ST V/R 07/01/31

Return profile

Total return as filed — price change plus distributions reinvested · trailing figures to Apr 2026

1-year
+6.32%
3-year
+12.43%
5-year
+7.56%
Volatility
3.51%
Worst 3-yr fall
-3.52%
Cumulative return· Jul 2023 – Apr 2026

May 2026 and Jun 2026 have been filed since the trailing figures were struck, so they are not in the table above or the curve — every figure here shares one cut-off, which is what makes them comparable with other funds.

Debt profile

What this fund holds — value-weighted across its bond and securitized long positions · as of 2026-06-30

Avg coupon
4.76%
Avg maturity
14.86 yr
Coupon type

Share of the fund's debt by how its coupon behaves — the fact that decides whether a rate move reaches this portfolio at all.

20%
floating
Fixed rate80.3%
Floating rate19.7%
Maturity ladder

Share of the fund's debt value in each maturity band, shortest first.

<1y10y+
<1y1.7%
1-3y4.4%
3-5y4.5%
5-10y21.6%
10y+67.7%
Flagged holdings
Defaulted: 0.00% · $0.48M · 2 positions
In arrears: none reported
Paid in kind: none reported

These three overlap — one holding can be in arrears and paying in kind at once — so they are shown separately and never summed.

Risk profile

Interest-rate and credit-spread sensitivity, both in years · as of 2026Q2

More of this fund’s sensitivity sits in credit spreads than in interest rates — a rate rally that comes with a credit selloff works against it.

Interest-rate duration
4.69 yr
approx. move per 100bp
Credit-spread duration
5.45 yr
approx. move per 100bp
If rates and spreads both rise 100bp

Where the loss would come from. The two shocks are the same size, so this is the balance of the fund's two sensitivities rather than a bet on one moving more.

≈ -10.0%
of value
Credit spreads54%
Interest rates46%

Filers report the impact of a 0.01% move only, so the total is our own scaling of that one number and overstates the loss on most bonds — read it as approximate, never as precise. The two sensitivities overlap rather than add up: they measure the same positions against different shocks, which is why the durations above are shown side by side and never summed.

Credit risk by quality

Share of the fund's spread duration carried by each credit tier.

+5.45
yrs total
Investment grade+5.37 yr
High yield+0.08 yr
Where the risk sits on the curve

Share of duration at each point, shortest first. A positive figure loses value when spreads widen; a negative one offsets — a credit hedge.

Interest rate4.69 yr total
3 mo30 yr
3 mo0.02 yr0%
1 yr0.30 yr6%
5 yr1.92 yr41%
10 yr2.27 yr48%
30 yr0.18 yr4%
Credit spread5.45 yr total
3 mo30 yr
3 mo0.25 yr5%
1 yr0.33 yr6%
5 yr2.20 yr40%
10 yr2.54 yr47%
30 yr0.13 yr2%

The two bands measure the same positions against different shocks and do not add — a Treasury carries rate duration and no spread duration, a floating-rate credit the reverse. Rate tenors are also summed across every currency the fund discloses.

Show the numbers
TenorRate yrsIG yrsHY yrsIG $/bpHY $/bp
3 mo+0.02+0.25+0.00$526.2k$843
1 yr+0.30+0.33+0.01$677.4k$14.0k
5 yr+1.92+2.17+0.03$4.51m$64.4k
10 yr+2.27+2.50+0.03$5.21m$63.9k
30 yr+0.18+0.12+0.01$247.1k$18.8k

Dollar change per 1bp of spread movement, as filed and sign-anchored. A blank cell was not filed; a zero was.

Holdings

By % of NAV · equity positions carry filed share counts · every resolvable issuer links to its company page

Issuer%NAVValue
FIDELITY INV MMKT GOVT-INST0.94%$195.56M
SOUTHEAST ENERGY A 5% 10/01/305.00% · due 2030-10-010.46%$94.71M
KENTUCKY ST PUBLI V/R 01/01/555.00% floating · due 2055-01-010.37%$77.64M
CALIFORNIA CMNTY V/R 01/01/555.00% floating · due 2055-01-010.29%$60.88M
PUERTO RICO SA 4.329% 07/01/404.33% · due 2040-07-010.28%$57.25M
MIAMI-DADE CNTY FL 5% 10/01/325.00% · due 2032-10-010.26%$54.75M
CHICAGO IL BRD OF 6% 04/01/466.00% · due 2046-04-010.26%$53.65M
MAIN STREET ENERGY 5% 10/01/335.00% · due 2033-10-010.25%$51.64M
BLACK BELT ENERGY 5% 11/01/365.00% · due 2036-11-010.24%$50.57M
UNIV OF TEXAS TX V/R 08/01/561.45% floating · due 2056-08-010.24%$50.00M
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Top 10 positions are 3.59% of net assets, top 25 6.72%, across 5.3K issuers.

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