ETF · holdings as filed 2026-04-30
What's inside MCBCX? MFS Core Bond Fund
Holdings 307 positions in the fund
Expense ratio 1.39% net, per year
Fund size $34M total net assets Top 20 holdings Rank Logo Ticker / Name Weight 1 ?
— MFS Institutional Money Market Portfolio
4.63% 2 BOND
US Treasury Note 4.25% · Jun 2029
4.16% 3 BOND
US Treasury Note 4.5% · Feb 2044
2.65% 4 BOND
US Treasury Note 2.375% · Feb 2042
2.60% 5 BOND
US Treasury Note 3.5% · Sep 2027
1.70% 6 BOND
US Treasury Note 4.5% · Apr 2027
1.58% 7 BOND
US Treasury Note 2.25% · Feb 2052
1.53% 8 BOND
US Treasury Note 4.25% · Feb 2054
1.31% 9 BOND
US Treasury Note 3.875% · Jul 2030
1.28% 10 BOND
Ntt Finance 5.502% · Jul 2035
1.16% 11 BOND
Fncl 3.5 5/11
1.10% 12 BOND
US Treasury Note 4.5% · Nov 2054
1.08% 13 BOND
US Treasury Note 4% · Nov 2052
0.93% 14 BOND
US Treasury Note 4.625% · Nov 2045
0.88% 15 BOND
US Treasury Note 4.125% · Jul 2028
0.86% 16 BOND
Fannie Mae mortgage pool #FN MA4563
0.80% 17 BOND
Bank Of America (floating) 2.572% · Oct 2032
0.77% 18 BOND
Bcc 2022-1a Cr
0.71% 19 BOND
Drslf 2020-86a Br2
0.71% 20 BOND
Drslf 2019-68a Brr
0.71%
Show more (20 more)
Sectors tap a row to see its top 10 holdings
› 1 Bonds & Fixed Income 79.6% › › Top holdings — Bonds & Fixed Income
Your 10 largest positions in this sector
1
BOND
US Treasury Note 4.25% · Jun 2029
4.16% 2
BOND
US Treasury Note 4.5% · Feb 2044
2.65% 3
BOND
US Treasury Note 2.375% · Feb 2042
2.60% 4
BOND
US Treasury Note 3.5% · Sep 2027
1.70% 5
BOND
US Treasury Note 4.5% · Apr 2027
1.58% 6
BOND
US Treasury Note 2.25% · Feb 2052
1.53% 7
BOND
US Treasury Note 4.25% · Feb 2054
1.31% 8
BOND
US Treasury Note 3.875% · Jul 2030
1.28% 9
BOND
Ntt Finance 5.502% · Jul 2035
1.16% Geography tap a row to see its top 10 holdings
Top holdings — United States
Your 10 largest positions in this country
1
BOND
US Treasury Note 4.25% · Jun 2029
4.16% 2
BOND
US Treasury Note 4.5% · Feb 2044
2.65% 3
BOND
US Treasury Note 2.375% · Feb 2042
2.60% 4
BOND
US Treasury Note 3.5% · Sep 2027
1.70% 5
BOND
US Treasury Note 4.5% · Apr 2027
1.58% 6
BOND
US Treasury Note 2.25% · Feb 2052
1.53% 7
BOND
US Treasury Note 4.25% · Feb 2054
1.31% 8
BOND
US Treasury Note 3.875% · Jul 2030
1.28% 9
BOND
Ntt Finance 5.502% · Jul 2035
1.16% Geography reflects each issuer's registered business address per SEC EDGAR filings where available, falling back to the exchange or listing where no SEC filing exists — not necessarily where a company's stock is primarily listed (e.g. TSMC is classified as Taiwan even though its ADR trades on the NYSE).
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Unwrap your portfolio → Data source: official SEC Form N-PORT filings (as of 2026-04-30); expense ratio from SEC prospectus (risk/return) filings. Fund holdings are disclosed quarterly and may reflect a 60-day reporting delay.