FundWatcher
MRBFX
MFS Total Return Bond Fund
MFS Series Trust IX

Portfolio concentration

As of April 30, 2026 · N-PORT
Holdings
1073
Top-10 weight
16.54%
Effective holdings ?
184
Crowding ?
100.0

Holdings

As of April 30, 2026 · N-PORT
#SecurityTickerSharesValue% of fund
1 US TREASURY N/B — 270,100,000 $270.86M 3.28%
2 US TREASURY N/B — 177,950,000 $174.24M 2.11%
3 US TREASURY N/B — 167,000,000 $168.59M 2.04%
4 US TREASURY N/B — 183,300,000 $162.12M 1.96%
5 MFS Institutional Money Market Portfolio, Class A — 126,441,653 $126.45M 1.53%
6 US TREASURY N/B — 102,500,000 $101.99M 1.23%
7 US TREASURY N/B — 101,800,000 $95.27M 1.15%
8 US TREASURY N/B — 90,926,000 $93.00M 1.13%
9 US TREASURY N/B — 100,050,000 $92.29M 1.12%
10 FR SD8199 — 110,943,982 $89.19M 1.08%
11 US TREASURY N/B — 90,700,000 $85.95M 1.04%
12 US TREASURY N/B — 74,000,000 $71.81M 0.87%
13 US TREASURY N/B — 132,800,000 $68.44M 0.83%
14 US TREASURY N/B — 64,200,000 $64.52M 0.78%
15 US TREASURY N/B — 57,200,000 $56.73M 0.69%
16 US TREASURY N/B — 57,000,000 $56.14M 0.68%
17 US TREASURY N/B — 51,500,000 $49.98M 0.61%
18 US TREASURY N/B — 74,100,000 $47.40M 0.57%
19 MQGAU V4.442 06/21/33 144A MQGAU 47,217,000 $45.82M 0.55%
20 CHENIERE ENERGYP — 44,143,000 $45.05M 0.55%
21 US TREASURY N/B — 67,500,000 $44.81M 0.54%
22 US TREASURY N/B — 58,777,000 $44.77M 0.54%
23 US TREASURY N/B — 61,700,000 $44.66M 0.54%
24 US TREASURY N/B — 44,500,000 $43.95M 0.53%
25 LoanCore Issuer Ltd., Series 2021-CRE6, Class B — 42,852,000 $42.90M 0.52%
26 WELLS FARGO CO — 45,462,000 $42.18M 0.51%
27 BANK OF AMER CRP — 45,881,000 $40.87M 0.49%
28 Arbor Realty Commercial Real Estate Notes Ltd., Series 2022-FL1, Class D — 40,620,500 $40.62M 0.49%
29 LoanCore Issuer LLC, Series 2025-CRE8, Class AS — 39,804,000 $39.82M 0.48%
30 US TREASURY N/B — 38,000,000 $38.75M 0.47%
31 BXMT Ltd., Series 2021-FL4, Class B — 38,262,000 $37.85M 0.46%
32 DISCOVER FINANCIAL SERVICES COF 34,164,000 $37.25M 0.45%
33 BANK OF AMER CRP — 39,891,000 $36.94M 0.45%
34 Uniform Mortgage-Backed Security, TBA FNMA 41,275,000 $34.56M 0.42%
35 Iron Mountain Inc. — 35,950,000 $34.55M 0.42%
36 NRZT 2025-NQM4 A1 NRZT 34,384,046 $34.49M 0.42%
37 SUMITOMO MITSUI — 38,002,000 $34.34M 0.42%
38 Black Diamond CLO Ltd., Series 2021-1A, Class A2R — 34,041,667 $34.06M 0.41%
39 PENSKE AUTOMOTIVE GROUP REGD 3.75000000 PAG29 34,558,000 $33.13M 0.40%
40 TRANSDIGM INC SUB 4.625% 01-15-29 TDG/29 33,133,000 $32.69M 0.40%
41 UBSCM 2017-C7 A4 — 33,000,000 $32.55M 0.39%
42 PLAINS ALL AMER — 33,187,000 $32.13M 0.39%
43 ENEL FINANCE INTL NV REGD 144A P/P 3.50000000 ENELIM 30,284,000 $29.72M 0.36%
44 US TREASURY N/B — 30,800,000 $29.58M 0.36%
45 QUIKRETE HOLDINGS INC SR SECURED 144A 03/32 6.375 QUIKHO 28,731,000 $29.18M 0.35%
46 Venture 43 CLO Ltd — 28,707,969 $28.66M 0.35%
47 ARDN Mortgage Trust, Series 2025-ARCP, Class B — 28,383,000 $28.39M 0.34%
48 SAMMONS FINL. GRP. 6.875% SAMMON 26,615,000 $28.18M 0.34%
49 MITSUB UFJ FIN — 31,223,000 $28.17M 0.34%
50 JPMORGAN CHASE — 28,117,000 $27.89M 0.34%
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