MFSMvsMBBETF Comparison
VS
MFS Active Intermediate Muni Bond ETF (MFSM) belongs to the Municipal Bonds segment. iShares MBS ETF (MBB) is part of the MBS & ABS segment. MFSM's top 1 sector exposures are Municipal. In contrast, MBB's top sector exposures are Industrials, Non-Corporate and Finance. MFSM is more expensive with a Total Expense Ratio (TER) of 0.34%, versus 0.04% for MBB. MFSM is down -0.57% year-to-date (YTD) with +$73M in YTD flows. MBB performs worse with -1.03% YTD performance, and -$1.79B in YTD flows. Run a side-by-side ETF comparison of MFSM and MBB below, and assess how they stack up in performance, liquidity, risk, exposure, holdings, and more, helping you select the best ETF for your investments.
Find out how industry players manage ETF portfolios. Discover our library of Model portfolios
MFSM vs MBB performance and flow charts
Performance
Cumulative Flows
Historic performance and flows
Data as of 10/23/2026
| 1M | 3M | YTD | 1Y | 3Y | 5Y | ||
|---|---|---|---|---|---|---|---|
| Perf. | MFSM MBB | +1.69%+1.09% | -1.09%-0.64% | -0.57%-1.03% | -0.09%-0.66% | n/a+19.63% | n/a+0.48% |
| Flows | MFSM MBB | +$18M-$3.31B | +$24M-$2.66B | +$73M-$1.79B | +$75M-$4.86B | -+$7.95B | -+$13.59B |
Volatility and drawdown
| 3M | 1Y | 3Y | 5Y | ||
|---|---|---|---|---|---|
| Volatility | MFSM MBB | +5.38%+5.98% | +3.32%+4.70% | n/a+5.71% | n/a+6.68% |
| Max drawdown | MFSM MBB | -5.93%-4.27% | -6.71%-5.38% | n/a-5.38% | n/a-16.94% |
| Max drawdown duration | MFSM MBB | 71d59d | 109d236d | n/a236d | n/a1405d |
Trading data
MFSM | MBB | |
Last sale 10/23/2026 at 1:30 PM | $24.20 | $91.29 |
| Previous close 10/22/2026 | $24.19 | $91.38 |
| Consolidated volume 10/22/2026 | ||
| Average volume 30 days | ||
| Average discount or premium 30 days | ||
| Average Bid/Ask spread 30 days |
Replication quality
Data as of September 30, 2026
1-year trailing difference
Create an account to view replication metrics
Join for free
MFSM
is actively managed and doesn’t replicate an indexMFSM | MBB | |
|---|---|---|
| Tracking error | ||
| Tracking difference | ||
| 1 year cumulative return difference | ||
| Best | ||
| Worst | ||
| Daily return difference | ||
| Average | ||
| Worst | ||
Advertisement
Main metrics
Last update 10/23/2026 at 1:30 PM
Live
Closed
MFSM | MBB | |
|---|---|---|
| Last price | $24.20 | $91.29 |
| 1D performance | +0.04% | -0.10% |
| AuM | $122.17 M | $35.54 B |
| E/R | 0.34% | 0.04% |
Advertisement
Exposure
Countries
MFSM
USA
25.81%
Other
74.19%
MBB
USA
28.44%
Other
71.56%
Sectors
MFSM
Municipal
25.81%
Other
74.19%
MBB
Industrials
20.61%
Non-Corporate
7.6%
Other
71.79%
Advertisement
Diversification
MFSM
Total weight of top 15 holdings out of 15
9.44%
MBB
Total weight of top 15 holdings out of 15
16.82%
Top 15 holdings
Data as of August 31, 2026
MFSM
US60416UV512
0.91%
Oklahoma Public Property Authority, 5% 1jun2034, USD (2026)
0.80%
Missouri Health and Educational Facilities Authority, 5% 1apr2036, USD (2026A)
0.80%
California Community Choice Financing Authority, 5% 1dec2055, USD (2025C)
0.70%
US763056DQ86
0.68%
US702538FE43
0.68%
US95235TAW36
0.66%
US10623ADK60
0.54%
Paulding Hospital Authority, 5% 1apr2036, USD
0.53%
US49121DAB82
0.53%
St. Tammany Parish Hospital Service District №1, 5% 1jul2056, USD (2026A)
0.52%
St. Cloud, 5% 1may2036, USD (2026)
0.52%
Austin, 5% 15nov2034, USD (2026B)
0.52%
US75989FAM59
0.52%
US897579CQ99
0.52%
MBB
BlackRock Cash Funds - Institutional
7.60%
US01F0526982
1.26%
US21H0526945
1.05%
FR SD8146, 2% 1may2051, USD (ABS)
0.98%
US01F0506927
0.87%
US21H0606978
0.63%
G2 MB0025, 5% 20nov2054, USD (ABS)
0.55%
US21H0506988
0.55%
G2 MA7648, 2% 20oct2051, USD (ABS)
0.51%
US36179WTX64
0.50%
FN MA4492, 2% 1dec2051, USD (ABS)
0.49%
US36179WJR07
0.48%
US21H0426955
0.48%
FR SD8140, 2% 1apr2051, USD (ABS)
0.47%
FN MA4465, 2% 1nov2051, USD (ABS)
0.42%
Frequently asked questions about MFSM and MBB
How have the MFSM and MBB ETFs performed in 2026?
As of October 23, 2026, MFSM is down -0.57% year-to-date (YTD), while MBB has lost -1.03%. That puts MFSM better performer ahead so far this year.
Which ETF is attracting more investor money: MFSM or MBB?
Year-to-date, the MFSM ETF saw +$73M in flows, compared to -$1.79B for MBB.
Which ETF is more volatile: MFSM or MBB?
Over the past year, MFSM had a volatility of 3.32%, while MBB experienced 4.7%.
Which ETF is bigger: MFSM or MBB?
As of October 23, 2026, MFSM holds $122.17 M in assets under management (AUM), while MBB manages $35.54 B.
What sectors do the MFSM and MBB ETFs invest in?
MFSM leans toward sectors like Municipal. Meanwhile, MBB focuses on Industrials and Non-Corporate.
What are the top holdings of the MFSM ETF and MBB ETF?
MFSM top holdings include US60416UV512, Oklahoma Public Property Authority, 5% 1jun2034, USD (2026) and Missouri Health and Educational Facilities Authority, 5% 1apr2036, USD (2026A). MBB holds in its top three: BlackRock Cash Funds - Institutional, US01F0526982 and US21H0526945.
Which ETF is more diversified: MFSM or MBB?
MFSM holds 418 securities with 9.44% of its assets in the top 15. MBB has 9405 securities and a top 15 weight of 16.82%.
Advertisement
Latest news about MFSM & MBB
The Weekly ETF Market Monitor (September 28-October 2, 2026)
October 2, 2026
MBB
What's the Fund | MFS Active Intermediate Muni Bond ETF (MFSM)
July 25, 2025
MFSM
NYSE x ETF Central ETF Education Series
March 5, 2024
MBB
Advertisement
Advertisement
