NPORT-EX 2 edgar.htm NPORT PART F
Quarterly Report
May 31, 2025
MFS®  Government    
Securities Fund
MFG-Q1
Portfolio of Investments
5/31/25 (unaudited)
The Portfolio of Investments is a complete list of all securities owned by your fund. It is categorized by broad-based asset classes.
Issuer     Shares/Par Value ($)
Bonds – 98.6%
Asset-Backed & Securitized – 8.1%
3650R Commercial Mortgage Trust, 2021-PF1, “XA”, 1%, 11/15/2054 (i)   $ 21,542,304 $846,828
ACREC 2021-FL1 Ltd., “AS”, FLR, 5.943% ((SOFR - 1mo. + 0.11448%) + 1.5%), 10/16/2036 (n)     7,778,000 7,750,115
ACREC 2023-FL2 LLC, “A”, FLR, 6.559% (SOFR - 1mo. + 2.23%), 2/19/2038 (n)     4,606,627 4,612,377
Alinea CLO Ltd., 2018-1A, “AR”, FLR, 5.169% (SOFR - 3mo. + 0.9%), 7/20/2031 (n)     3,421,955 3,419,617
American Credit Acceptance Receivables Trust, 2024-2, “A”, 5.9%, 2/12/2027 (n)     723,004 723,633
AmeriCredit Automobile Receivables Trust, 2024-1, “A2-B”, FLR, 4.928% (SOFR - 1mo. + 0.6%), 2/18/2028      3,181,989 3,180,876
Arbor Realty Trust, Inc., CLO, 2021-FL3, “AS”, FLR, 5.843% ((SOFR - 1mo. + 0.11448%) + 1.4%), 8/15/2034 (n)     6,638,000 6,623,562
AREIT 2022-CRE6 Trust, “AS”, FLR, 5.978% (SOFR - 30 day + 1.65%), 1/20/2037 (n)     7,155,500 7,131,110
ARI Fleet Lease Trust, 2023-B, “A2”, 6.05%, 7/15/2032 (n)     1,081,337 1,089,451
BBCMS Mortgage Trust, 2021-C10, “XA”, 1.207%, 7/15/2054 (i)     19,636,139 1,053,351
BBCMS Mortgage Trust, 2021-C9, “XA”, 1.578%, 2/15/2054 (i)     13,493,630 922,062
BBCMS Mortgage Trust, 2022-C18, “XA”, 0.464%, 12/15/2055 (i)     22,898,404 779,347
BDS 2024-FL13 Ltd., “A”, FLR, 5.903% (SOFR - 1mo. + 1.5762%), 9/19/2039 (n)     1,558,000 1,548,727
Benchmark 2021-B23 Mortgage Trust, “XA”, 1.255%, 2/15/2054 (i)     43,316,439 2,195,897
Benchmark 2021-B24 Mortgage Trust, “XA”, 1.135%, 3/15/2054 (i)     26,131,161 1,122,302
Benchmark 2021-B26 Mortgage Trust, “XA”, 0.881%, 6/15/2054 (i)     38,063,916 1,337,581
Benchmark 2021-B27 Mortgage Trust, “XA”, 1.234%, 7/15/2054 (i)     32,736,201 1,741,461
Benchmark 2021-B28 Mortgage Trust, “XA”, 1.256%, 8/15/2054 (i)     39,581,480 2,145,391
Benchmark 2021-B29 Mortgage Trust, “XA”, 1.018%, 9/15/2054 (i)     44,840,690 1,754,015
Bridgecrest Lending Auto Securitization Trust, 2024-2, “A2”, 5.78%, 2/16/2027      97,515 97,563
Bridgecrest Lending Auto Securitization Trust, 2025-1, “A2”, 4.71%, 9/15/2027      3,656,000 3,654,582
BSPDF 2021-FL1 Issuer Ltd., “AS”, FLR, 5.923% ((SOFR - 1mo. + 0.11448%) + 1.48%), 10/15/2036 (n)     1,841,419 1,834,110
Business Jet Securities LLC, 2024-1A, “A”, 6.197%, 5/15/2039 (n)     1,270,240 1,290,456
BXMT 2021-FL4 Ltd., “AS”, FLR, 5.743% ((SOFR - 1mo. + 0.11448%) + 1.3%), 5/15/2038 (n)     7,779,500 7,601,920
Chesapeake Funding II LLC, 2023-2A, “A2”, FLR, 5.432% (SOFR - 30 day + 1.1%), 10/15/2035 (n)     2,061,696 2,070,174
Citigroup Commercial Mortgage Trust, 2019-XA, “C7”, 0.818%, 12/15/2072 (i)(n)     21,295,260 685,190
Commercial Mortgage Pass-Through Certificates, 2021-BN31, “XA”, 1.281%, 2/15/2054 (i)     32,664,402 1,840,678
Commercial Mortgage Pass-Through Certificates, 2021-BN32, “XA”, 0.763%, 4/15/2054 (i)     18,875,143 597,946
Commercial Mortgage Pass-Through Certificates, 2021-BN35, “XA”, 1.03%, 6/15/2064 (i)     13,174,386 593,518
Commercial Mortgage Pass-Through Certificates, 2024-CBM, “A2”, 5.867%, 12/10/2041 (n)     1,395,974 1,410,596
Enterprise Fleet Financing 2025-1 LLC, “A2”, 4.65%, 10/20/2027 (n)     1,207,000 1,207,814
EQT Trust, 2024-EXTR, “B”, 5.655%, 7/05/2041 (n)     1,503,054 1,516,150
GLS Auto Select Receivables Trust, 2023-2A, 6.37%, 6/15/2028 (n)     1,192,653 1,202,198
GLS Auto Select Receivables Trust, 2024-2A, “A-2”, 5.77%, 6/15/2027 (n)     1,598,152 1,600,893
KREF 2018-FT1 Ltd., “AS”, FLR, 5.743% ((SOFR - 1mo. + 0.11448%) + 1.3%), 2/15/2039 (n)     759,000 753,560
LAD Auto Receivables Trust, 2022-1A, “A”, 5.21%, 6/15/2027 (n)     113,918 114,007
LAD Auto Receivables Trust, 2025-1A, “A2”, 4.6%, 12/15/2027 (n)     3,919,000 3,915,061
LoanCore 2021-CRE5 Ltd., “AS”, FLR, 6.193% ((SOFR - 1mo. + 0.11448%) + 1.75%), 7/15/2036 (n)     6,508,500 6,503,183
LoanCore 2021-CRE6 Ltd., “AS”, FLR, 6.093% ((SOFR - 1mo. + 0.11448%) + 1.65%), 11/15/2038 (n)     10,000,000 9,930,860
M&T Bank Auto Receivables Trust, 2025-1, “A-2A”, 4.63%, 5/15/2028 (n)     2,528,000 2,526,364
MF1 2021-FL5 Ltd., “AS”, FLR, 5.643% ((SOFR - 1mo. + 0.11448%) + 1.2%), 7/15/2036 (n)     3,682,631 3,669,156
MF1 2021-FL5 Ltd., “B”, FLR, 5.893% ((SOFR - 1mo. + 0.11448%) + 1.45%), 7/15/2036 (n)     4,881,500 4,817,148
MF1 2021-FL7 Ltd., “A”, FLR, 5.521% ((SOFR - 1mo. + 0.11448%) + 1.08%), 10/16/2036 (n)     4,523,715 4,518,829
Morgan Stanley Capital I Trust, 2018-H4, “XA”, 0.8%, 12/15/2051 (i)     21,806,426 519,405
Morgan Stanley Capital I Trust, 2021-L5, “XA”, 1.277%, 5/15/2054 (i)     16,624,648 831,766
Morgan Stanley Capital I Trust, 2021-L6, “XA”, 1.172%, 6/15/2054 (i)     19,729,729 868,256
Morgan Stanley Capital I Trust, 2021-L7, “XA”, 1.079%, 10/15/2054 (i)     79,655,789 3,488,860
Morgan Stanley Residential Mortgage Loan Trust, 2024-NQM1, “A-1”, 6.152%, 12/25/2068 (n)     4,560,649 4,585,524
Morgan Stanley Residential Mortgage Loan Trust, 2024-NQM3, “A-1”, 5.044%, 7/25/2069 (n)     1,809,781 1,796,000
Morgan Stanley Residential Mortgage Loan Trust, 2025-NQM3, “A-1”, 5.53%, 5/25/2070 (n)     2,809,920 2,812,869
Navistar Financial Dealer Note Master Owner Trust, 2023-1, “A”, 6.18%, 8/25/2028 (n)     1,299,000 1,303,148
Navistar Financial Dealer Note Master Owner Trust, 2023-1, “B”, 6.48%, 8/25/2028 (n)     1,379,000 1,383,658
OBX Trust, 2024-NQM1, “A2”, 6.253%, 11/25/2063 (n)     511,283 514,481
OBX Trust, 2025-NQM8, “A1”, 5.472%, 3/25/2065 (n)     2,517,310 2,521,182
PFS Financing Corp., 2023-C, “B”, 5.91%, 10/15/2028 (n)     1,302,000 1,315,637
PFS Financing Corp., 2025-A, “A”, FLR, 4.982% (SOFR - 1mo. + 0.65%), 1/15/2029 (n)     4,611,000 4,607,356
1
Portfolio of Investments (unaudited) – continued
Issuer     Shares/Par Value ($)
Bonds – continued
Asset-Backed & Securitized – continued
Provident Funding Mortgage Trust, 2024-1, “A3”, 5.5%, 12/25/2054 (n)   $ 2,877,237 $2,864,338
ReadyCap Commercial Mortgage Trust, 2021-FL7, “A”, FLR, 5.639% ((SOFR - 1mo. + 0.11448%) + 1.2%), 11/25/2036 (n)     1,547,168 1,545,944
ReadyCap Commercial Mortgage Trust, 2021-FL7, “AS”, FLR, 5.939% ((SOFR - 1mo. + 0.11448%) + 1.5%), 11/25/2036 (n)     1,261,500 1,260,757
Verus Securitization Trust, 2024-1, “A2”, 5.915%, 1/25/2069 (n)     1,193,239 1,195,127
Verus Securitization Trust, 2024-4, “A1”, 6.218%, 6/25/2069 (n)     2,336,380 2,354,025
Wells Fargo Commercial Mortgage Trust, 2018-C48, “XA”, 0.931%, 1/15/2052 (i)(n)     12,232,852 318,191
Wells Fargo Commercial Mortgage Trust, 2021-C60, “XA”, 1.493%, 8/15/2054 (i)     20,214,852 1,335,537
Westlake Automobile Receivables Trust, 2024-1A, “A2B”, FLR, 4.901% (SOFR - 1mo. + 0.57%), 3/15/2027 (n)     910,795 910,965
        $152,262,685
Consumer Services – 0.1%
Conservation Fund, 3.474%, 12/15/2029    $ 2,018,000 $1,892,667
Industrial – 0.0%
Howard University, Washington D.C., AGM, 2.516%, 10/01/2025    $ 688,000 $680,857
Mortgage-Backed – 62.0%  
Fannie Mae, 2.908%, 7/25/2027    $ 10,366,665 $10,102,921
Fannie Mae, 3%, 11/01/2028 - 9/01/2046      42,303,733 40,366,514
Fannie Mae, 3.5%, 1/25/2030 - 6/25/2048      28,800,319 26,410,152
Fannie Mae, 2.5%, 11/01/2031 - 10/01/2046      4,323,294 3,993,729
Fannie Mae, 3.5%, 12/25/2031 - 2/25/2036 (i)     843,098 63,190
Fannie Mae, 6.5%, 1/01/2032 - 10/01/2037      475,580 495,792
Fannie Mae, 6%, 1/01/2033 - 12/01/2037      1,202,701 1,237,891
Fannie Mae, 3%, 2/25/2033 - 1/25/2052 (i)     1,466,829 144,421
Fannie Mae, 5.5%, 5/01/2033 - 5/01/2044      5,715,624 5,824,301
Fannie Mae, 5%, 11/01/2033 - 3/25/2042      6,964,212 6,988,986
Fannie Mae, 4.5%, 3/01/2034 - 6/01/2044      14,457,283 14,198,057
Fannie Mae, 4.886%, 4/25/2034 - 11/25/2046      6,215,061 6,135,512
Fannie Mae, 4.726%, 1/25/2036      43,184 43,171
Fannie Mae, 4%, 9/01/2040 - 7/01/2047      28,365,692 26,923,693
Fannie Mae, 1%, 3/25/2041      1,481,177 1,291,153
Fannie Mae, 4.786%, 3/25/2041      374,456 372,423
Fannie Mae, 2.25%, 4/25/2041      1,383,582 1,318,901
Fannie Mae, 4.936%, 7/25/2041 - 12/25/2049      4,621,537 4,524,227
Fannie Mae, 1.75%, 9/25/2041      1,070,829 1,020,751
Fannie Mae, 2.75%, 9/25/2042      946,226 909,679
Fannie Mae, 2%, 8/25/2044 - 4/25/2046      1,977,298 1,829,315
Fannie Mae, 4.736%, 12/25/2045      586,720 576,664
Fannie Mae, 1.563%, 9/25/2046 (i)     1,715,131 178,455
Fannie Mae, 4%, 9/25/2050 (i)     2,958,188 586,475
Fannie Mae, 5.121%, 10/25/2052      7,710,762 7,460,800
Fannie Mae, 5.772%, 11/25/2053 - 1/25/2055      13,074,511 13,094,013
Fannie Mae, 5.222%, 12/25/2053      5,810,796 5,804,524
Fannie Mae, 5.472%, 6/25/2054 - 2/25/2055      17,355,023 17,316,866
Fannie Mae, 7.322%, 7/25/2054      3,375,471 3,385,951
Fannie Mae, 5.172%, 1/25/2055      4,221,163 4,208,127
Fannie Mae, 6.762%, 3/25/2055      4,705,530 4,663,200
Fannie Mae, UMBS, 2.5%, 5/01/2036 - 8/01/2052      107,991,727 89,670,736
Fannie Mae, UMBS, 5.5%, 10/01/2038 - 8/01/2054      25,542,156 25,339,533
Fannie Mae, UMBS, 1.5%, 2/01/2042 - 3/01/2051      1,391,660 1,057,986
Fannie Mae, UMBS, 2%, 2/01/2042 - 3/01/2052      60,702,001 48,600,175
Fannie Mae, UMBS, 3.5%, 5/01/2049 - 2/01/2052      1,983,007 1,786,339
Fannie Mae, UMBS, 3%, 6/01/2051 - 8/01/2052      20,655,004 17,714,644
Fannie Mae, UMBS, 4%, 8/01/2051 - 2/01/2053      5,552,896 5,156,280
Fannie Mae, UMBS, 4.5%, 9/01/2052      1,779,419 1,690,846
Fannie Mae, UMBS, 5%, 9/01/2052 - 11/01/2054      1,733,761 1,679,924
Fannie Mae, UMBS, 6%, 6/01/2053 - 10/01/2054      16,600,899 16,783,189
Freddie Mac, 4%, 7/01/2025 - 1/15/2055      5,895,111 5,730,805
2
Portfolio of Investments (unaudited) – continued
Issuer     Shares/Par Value ($)
Bonds – continued
Mortgage-Backed – continued  
Freddie Mac, 4.5%, 7/01/2025 - 5/01/2042    $ 4,440,655 $4,396,415
Freddie Mac, 3.75%, 8/25/2025      1,716,522 1,710,131
Freddie Mac, 3.5%, 11/15/2025 - 10/25/2058      28,148,179 26,544,563
Freddie Mac, 2.745%, 1/25/2026      3,355,892 3,315,413
Freddie Mac, 3.208%, 2/25/2026      1,888,953 1,873,177
Freddie Mac, 2.57%, 7/25/2026      31,378,495 30,793,129
Freddie Mac, 3.12%, 9/25/2026      12,661,384 12,453,759
Freddie Mac, 2.525%, 10/25/2026      10,822,583 10,563,723
Freddie Mac, 2.797%, 12/25/2026      1,122,311 1,108,761
Freddie Mac, 3.413%, 12/25/2026      16,700,000 16,454,804
Freddie Mac, 1.373%, 3/25/2027 (i)     5,583,000 123,506
Freddie Mac, 3.243%, 4/25/2027      10,090,226 9,898,586
Freddie Mac, 3.117%, 6/25/2027      20,616,052 20,176,573
Freddie Mac, 0.563%, 7/25/2027 (i)     99,980,789 993,509
Freddie Mac, 0.408%, 8/25/2027 (i)     77,572,389 615,808
Freddie Mac, 1.47%, 9/25/2027      4,600,000 4,325,939
Freddie Mac, 3.286%, 11/25/2027      6,876,682 6,723,585
Freddie Mac, 0.362%, 12/25/2027 (i)     1,346,191 10,893
Freddie Mac, 1.603%, 12/25/2027      8,595,852 8,065,393
Freddie Mac, 0.294%, 1/25/2028 (i)     137,852,173 1,006,665
Freddie Mac, 0.299%, 1/25/2028 (i)     57,691,720 426,498
Freddie Mac, 0.129%, 2/25/2028 (i)     166,625,635 619,981
Freddie Mac, 0.115%, 4/25/2028 (i)     109,560,122 421,763
Freddie Mac, 3.9%, 4/25/2028      1,867,674 1,850,557
Freddie Mac, 3%, 6/15/2028 - 2/25/2059      24,603,983 22,724,182
Freddie Mac, 0.425%, 10/25/2028 (i)     39,461,071 553,876
Freddie Mac, 0.443%, 5/25/2029 (i)     58,815,424 988,540
Freddie Mac, 0.816%, 7/25/2029 (i)     31,354,116 988,470
Freddie Mac, 1.085%, 7/25/2029 (i)     18,907,077 713,837
Freddie Mac, 1.137%, 8/25/2029 (i)     33,175,464 1,342,774
Freddie Mac, 0.571%, 1/25/2030 (i)     19,154,523 465,974
Freddie Mac, 1.316%, 1/25/2030 (i)     26,454,280 1,361,655
Freddie Mac, 1.587%, 1/25/2030 (i)     19,346,318 1,175,654
Freddie Mac, 1.797%, 4/25/2030 (i)     14,430,646 1,091,615
Freddie Mac, 1.838%, 4/25/2030 (i)     20,077,463 1,553,078
Freddie Mac, 1.665%, 5/25/2030 (i)     12,033,779 873,132
Freddie Mac, 1.798%, 5/25/2030 (i)     26,880,424 2,090,485
Freddie Mac, 5.5%, 6/01/2030 - 9/01/2041      2,489,149 2,540,641
Freddie Mac, 1.113%, 6/25/2030 (i)     19,932,253 928,400
Freddie Mac, 1.341%, 6/25/2030 (i)     11,124,134 657,297
Freddie Mac, 1.375%, 6/25/2030 (i)     29,439,894 1,640,747
Freddie Mac, 1.597%, 8/25/2030 (i)     10,235,210 736,341
Freddie Mac, 1.168%, 9/25/2030 (i)     6,568,138 352,571
Freddie Mac, 1.08%, 11/25/2030 (i)     13,158,725 672,769
Freddie Mac, 0.322%, 1/25/2031 (i)     49,831,338 702,432
Freddie Mac, 0.536%, 1/25/2031 - 9/25/2031 (i)     120,996,513 3,379,040
Freddie Mac, 0.78%, 1/25/2031 (i)     19,512,958 750,425
Freddie Mac, 0.935%, 1/25/2031 (i)     14,681,587 668,341
Freddie Mac, 0.355%, 2/25/2031 (i)     18,431,877 398,082
Freddie Mac, 0.511%, 3/25/2031 (i)     40,043,489 954,925
Freddie Mac, 0.731%, 3/25/2031 (i)     17,260,719 647,115
Freddie Mac, 1.214%, 5/25/2031 - 7/25/2031 (i)     29,681,096 1,874,849
Freddie Mac, 0.938%, 7/25/2031 (i)     11,674,001 584,787
Freddie Mac, 0.507%, 8/25/2031 (i)     14,870,513 387,356
Freddie Mac, 0.855%, 9/25/2031 (i)     48,419,608 2,179,768
Freddie Mac, 0.349%, 11/25/2031 (i)     73,361,326 1,467,028
Freddie Mac, 0.496%, 12/25/2031 (i)     73,957,916 2,035,448
Freddie Mac, 0.567%, 12/25/2031 (i)     12,187,459 372,312
Freddie Mac, 0.766%, 2/25/2032 (i)     49,680,895 2,160,175
3
Portfolio of Investments (unaudited) – continued
Issuer     Shares/Par Value ($)
Bonds – continued
Mortgage-Backed – continued  
Freddie Mac, 0.32%, 6/25/2032 (i)   $ 116,203,070 $2,420,463
Freddie Mac, 4.897%, 11/15/2032      38,225 38,066
Freddie Mac, 0.154%, 11/25/2032 (i)     74,026,378 976,645
Freddie Mac, 0.266%, 5/25/2033 (i)     64,115,960 1,365,433
Freddie Mac, 0.128%, 8/25/2033 (i)     78,666,400 1,007,260
Freddie Mac, 0.176%, 10/25/2033 (i)     75,772,703 1,286,105
Freddie Mac, 5%, 5/01/2034 - 12/01/2054      13,169,318 13,034,104
Freddie Mac, 6%, 8/01/2034 - 10/01/2038      2,394,647 2,498,270
Freddie Mac, 0.905%, 9/25/2034 (i)     9,883,118 689,963
Freddie Mac, 0.055%, 1/25/2035 (i)     119,066,272 1,121,414
Freddie Mac, 0.247%, 1/25/2035 (i)     47,468,092 1,129,954
Freddie Mac, 5.5%, 2/15/2036 (i)     263,115 42,512
Freddie Mac, 6.5%, 5/01/2037      79,235 82,010
Freddie Mac, 4.5%, 12/15/2040 (i)     42,979 3,980
Freddie Mac, 1.75%, 8/15/2041      784,993 740,086
Freddie Mac, 4.847%, 8/15/2046      345,535 340,311
Freddie Mac, 2.5%, 3/25/2051 (i)     7,820,215 1,276,440
Freddie Mac, 5.142%, 9/25/2052      4,997,472 4,877,488
Freddie Mac, 5.771%, 10/25/2053      589,533 597,811
Freddie Mac, 6.551%, 12/25/2053      4,480,475 4,461,237
Freddie Mac, 5.222%, 10/25/2054      9,503,548 9,488,650
Freddie Mac, 6.772%, 1/25/2055      2,469,332 2,456,823
Freddie Mac, 5.272%, 2/25/2055      7,765,480 7,761,146
Freddie Mac, 5.922%, 2/25/2055      4,445,723 4,469,755
Freddie Mac, 3.25%, 11/25/2061      4,344,726 3,945,029
Freddie Mac, UMBS, 2.5%, 3/01/2037 - 9/01/2052      24,571,058 20,159,365
Freddie Mac, UMBS, 2%, 2/01/2042 - 3/01/2052      17,605,059 14,067,046
Freddie Mac, UMBS, 3.5%, 12/01/2046 - 5/01/2052      3,386,552 3,042,183
Freddie Mac, UMBS, 3%, 2/01/2050 - 8/01/2052      29,095,033 24,821,152
Freddie Mac, UMBS, 1.5%, 4/01/2051 - 11/01/2051      5,868,854 4,330,718
Freddie Mac, UMBS, 4%, 5/01/2052      3,987,184 3,684,605
Freddie Mac, UMBS, 5%, 11/01/2052 - 12/01/2054      15,121,298 14,662,080
Freddie Mac, UMBS, 5.5%, 12/01/2052 - 8/01/2054      16,847,072 16,704,158
Freddie Mac, UMBS, 6%, 2/01/2053 - 5/01/2054      11,305,967 11,441,342
Freddie Mac, UMBS, 6.5%, 4/01/2054      490,519 506,032
Ginnie Mae, 3.5%, 8/20/2029 - 1/20/2043 (i)     5,909,505 660,590
Ginnie Mae, 5.5%, 3/15/2033 - 10/20/2053      2,673,270 2,683,844
Ginnie Mae, 4.5%, 7/20/2033 - 5/20/2054      34,545,656 33,174,996
Ginnie Mae, 5.657%, 8/20/2034      724,519 737,368
Ginnie Mae, 4%, 5/16/2039 - 7/20/2052      3,469,203 3,259,009
Ginnie Mae, 5%, 8/20/2039 - 5/20/2055      22,919,582 22,301,967
Ginnie Mae, 4%, 12/20/2039 - 9/20/2047 (i)     1,636,900 242,822
Ginnie Mae, 0.961%, 5/20/2041 (i)     2,796,263 222,513
Ginnie Mae, 4.539%, 9/20/2041      7,751,237 7,540,836
Ginnie Mae, 3.5%, 12/15/2041 - 5/20/2055      18,211,909 16,364,318
Ginnie Mae, 2.5%, 6/20/2042 - 5/20/2052      22,446,018 18,818,892
Ginnie Mae, 3%, 2/20/2043 - 10/20/2052      27,446,693 24,038,503
Ginnie Mae, 4.739%, 10/20/2045      7,305,481 7,069,152
Ginnie Mae, 4.889%, 7/20/2046      2,843,840 2,776,504
Ginnie Mae, 1.711%, 4/20/2047 (i)     481,516 56,614
Ginnie Mae, 4.689%, 10/20/2047      553,008 531,979
Ginnie Mae, 2%, 11/20/2050 (i)     190,635 21,453
Ginnie Mae, 2.5%, 2/20/2051 (i)     2,287,869 278,963
Ginnie Mae, 2%, 1/20/2052 - 11/20/2052      35,294,462 28,360,038
Ginnie Mae, 6%, 2/20/2054 - 11/20/2055      9,900,987 10,122,074
Ginnie Mae, 5.378%, 10/20/2054      4,335,480 4,295,295
Ginnie Mae, 5.478%, 3/20/2064      1,359,343 1,363,364
Ginnie Mae, 5.113%, 7/20/2064      1,082,493 1,083,924
Ginnie Mae, 5.183%, 10/20/2066      1,370,488 1,373,588
4
Portfolio of Investments (unaudited) – continued
Issuer     Shares/Par Value ($)
Bonds – continued
Mortgage-Backed – continued  
Ginnie Mae, 5.203%, 10/20/2066    $ 3,793,912 $3,803,434
Ginnie Mae, 5.249%, 1/20/2067      3,217,751 3,246,962
Ginnie Mae, 5.127%, 2/20/2067      2,107,036 2,124,981
Ginnie Mae, 5.174%, 3/20/2067      4,770,671 4,815,050
Ginnie Mae, 6.417%, 7/20/2067      5,726,619 5,802,594
Ginnie Mae, 4.883%, 11/20/2067      1,791,008 1,796,914
Ginnie Mae, 4.992%, 4/20/2068      9,153,015 9,222,195
Ginnie Mae, 5.425%, 5/20/2068      6,451,540 6,490,752
Ginnie Mae, 4.933%, 11/20/2068 - 3/20/2070      7,363,769 7,373,150
Ginnie Mae, 4.963%, 7/20/2070      6,591,834 6,554,415
Ginnie Mae, 4.728%, 12/20/2071      3,039,960 3,025,085
Ginnie Mae, 4.978%, 8/20/2074 - 1/20/2075      13,463,836 13,453,575
Ginnie Mae, 4.328%, 11/20/2074      4,520,098 4,482,287
Ginnie Mae, 4.928%, 2/20/2075      6,842,010 6,805,693
Ginnie Mae, TBA, 5.5%, 6/15/2055      7,250,000 7,197,607
Ginnie Mae, TBA, 6%, 6/15/2055      10,725,000 10,827,245
Ginnie Mae, TBA, 6.5%, 6/15/2055      6,625,000 6,764,423
UMBS, TBA, 2%, 6/01/2055      31,225,000 24,256,252
UMBS, TBA, 3%, 6/25/2055      12,350,000 10,506,653
        $1,158,625,072
Municipals – 0.3%
Massachusetts Educational Financing Authority, Education Loan Rev., Taxable, “A”, 2.682%, 7/01/2027    $ 2,165,000 $2,085,963
Michigan Finance Authority Tobacco Settlement Asset-Backed Rev., Taxable (2006 Sold Tobacco Receipts), “A-1”, 2.326%, 6/01/2030      79,719 79,719
Port of Oakland, CA, Senior Lien Refunding Rev., Taxable, “R”, 1.517%, 5/01/2026      1,413,570 1,375,059
West Virginia Tobacco Settlement Financing Authority Asset-Backed Refunding, Taxable, “A-1”, 1.647%, 6/01/2025      1,550,000 1,550,000
        $5,090,741
U.S. Government Agencies and Equivalents – 0.1%
Small Business Administration, 2.21%, 2/01/2033    $ 488,886 $455,569
Small Business Administration, 2.22%, 3/01/2033      745,811 692,843
Small Business Administration, 3.15%, 7/01/2033      713,680 681,435
Small Business Administration, 3.16%, 8/01/2033      299,122 285,847
Small Business Administration, 3.62%, 9/01/2033      262,386 253,629
        $2,369,323
U.S. Treasury Obligations – 28.0%
U.S. Treasury Bonds, 6%, 2/15/2026 (f)   $ 5,933,000 $6,004,845
U.S. Treasury Bonds, 6.375%, 8/15/2027      2,309,000 2,430,042
U.S. Treasury Bonds, 4.375%, 2/15/2038      2,078,000 2,042,041
U.S. Treasury Bonds, 3.125%, 2/15/2043      9,748,800 7,683,654
U.S. Treasury Bonds, 2.875%, 5/15/2043      27,528,200 20,790,243
U.S. Treasury Bonds, 4.75%, 11/15/2043      11,168,000 10,949,439
U.S. Treasury Bonds, 2.5%, 2/15/2045      97,983,000 67,416,897
U.S. Treasury Bonds, 4.75%, 2/15/2045      36,531,000 35,657,681
U.S. Treasury Bonds, 4.625%, 5/15/2054      37,560,000 35,727,483
U.S. Treasury Bonds, 4.625%, 2/15/2055      11,722,000 11,179,858
U.S. Treasury Notes, 2.75%, 2/15/2028      54,157,000 52,599,986
U.S. Treasury Notes, 3.625%, 3/31/2028 (f)     86,350,000 85,810,313
U.S. Treasury Notes, 1%, 7/31/2028      32,248,000 29,509,439
U.S. Treasury Notes, 2.375%, 5/15/2029      19,515,500 18,424,614
U.S. Treasury Notes, 1.625%, 8/15/2029      29,405,000 26,849,292
U.S. Treasury Notes, 1.75%, 11/15/2029      8,564,000 7,814,650
U.S. Treasury Notes, 3.5%, 4/30/2030      18,675,000 18,279,615
U.S. Treasury Notes, 4.125%, 8/31/2030      37,647,000 37,861,705
U.S. Treasury Notes, 1.625%, 5/15/2031      41,833,000 36,447,001
5
Portfolio of Investments (unaudited) – continued
Issuer     Shares/Par Value ($)
Bonds – continued
U.S. Treasury Obligations – continued
U.S. Treasury Notes, 1.375%, 11/15/2031    $ 11,425,300 $9,648,130
        $523,126,928
Total Bonds   $1,844,048,273
Mutual Funds (h) – 4.7%
Money Market Funds – 4.7%  
MFS Institutional Money Market Portfolio, 4.35% (v)     88,505,301 $88,505,301
 
Other Assets, Less Liabilities – (3.3)%   (62,053,309)
Net Assets – 100.0% $1,870,500,265
(f) All or a portion of the security has been segregated as collateral for open futures contracts and cleared swap agreements.      
(h) An affiliated issuer, which may be considered one in which the fund owns 5% or more of the outstanding voting securities, or a company which is under common control. At period end, the aggregate values of the fund's investments in affiliated issuers and in unaffiliated issuers were $88,505,301 and $1,844,048,273, respectively.      
(i) Interest only security for which the fund receives interest on notional principal (Par amount). Par amount shown is the notional principal and does not reflect the cost of the security.      
(n) Securities exempt from registration under Rule 144A of the Securities Act of 1933. These securities may be sold in the ordinary course of business in transactions exempt from registration, normally to qualified institutional buyers. At period end, the aggregate value of these securities was $121,355,463, representing 6.5% of net assets.      
(v) Affiliated issuer that is available only to investment companies managed by MFS. The rate quoted for the MFS Institutional Money Market Portfolio is the annualized seven-day yield of the fund at period end.      
The following abbreviations are used in this report and are defined:
AGM Assured Guaranty Municipal
CLO Collateralized Loan Obligation
CPI-U Consumer Price Index - Urban Consumers
FLR Floating Rate. Interest rate resets periodically based on the parenthetically disclosed reference rate plus a spread (if any). The period-end rate reported may not be the current rate. All reference rates are USD unless otherwise noted.
SOFR Secured Overnight Financing Rate
TBA To Be Announced
UMBS Uniform Mortgage-Backed Security
Derivative Contracts at 5/31/25
Futures Contracts
Description Long/
Short 		Currency Contracts Notional
Amount 		Expiration
Date 		Value/Unrealized
Appreciation
(Depreciation)
Asset Derivatives
Interest Rate Futures 
U.S. Treasury Note 10 yr Long USD 877 $97,127,750 September – 2025 $174,758
U.S. Treasury Note 2 yr Long USD 1,169 242,494,438 September – 2025 351,963
U.S. Treasury Note 5 yr Long USD 2,570 278,041,875 September – 2025 415,112
U.S. Treasury Ultra Bond 30 yr Long USD 16 1,857,000 September – 2025 823
U.S. Treasury Ultra Note 10 yr Long USD 248 27,911,625 September – 2025 112,883
            $1,055,539
Cleared Swap Agreements
Maturity
Date 		Notional
Amount 		Counterparty Cash Flows
to Receive/
Frequency 		Cash Flows
to Pay/
Frequency 		Unrealized
Appreciation
(Depreciation) 		  Net Unamortized
Upfront Payments
(Receipts) 		  Value
Asset Derivatives          
Interest Rate Swaps           
5/08/27 USD 56,427,000 centrally cleared Daily SOFR / Annually 3.5595% / Annually $171,492   $—   $171,492
6
Portfolio of Investments (unaudited) – continued
Cleared Swap Agreements − continued
Maturity
Date 		Notional
Amount 		Counterparty Cash Flows
to Receive/
Frequency 		Cash Flows
to Pay/
Frequency 		Unrealized
Appreciation
(Depreciation) 		  Net Unamortized
Upfront Payments
(Receipts) 		  Value
Liability Derivatives          
Interest Rate Swaps           
5/24/26 USD 96,000,000 centrally cleared Daily SOFR / Annually 4.7585% / Annually $(672,241)   $—   $(672,241)
12/26/26 USD 23,950,000 centrally cleared Daily SOFR / Annually 4.1635% / Annually (109,503)   —   (109,503)
12/26/29 USD 45,500,000 centrally cleared Daily SOFR / Annually 4.085% / Annually (888,059)   —   (888,059)
            $(1,669,803)   $—   $(1,669,803)
Inflation Swaps           
5/14/30 USD 61,400,000 centrally cleared CPI-U / At Maturity 2.539% / At Maturity $(46,083)   $—   $(46,083)
            $(1,715,886)   $—   $(1,715,886)
At May 31, 2025, the fund had cash collateral of $514,103 and other liquid securities with an aggregate value of $11,286,656 to cover any collateral or margin obligations for certain derivative contracts.
See attached supplemental information. For more information see notes to financial statements as disclosed in the most recent semiannual or annual report.
7
Supplemental Information
5/31/25 (unaudited)
The fund is an investment company and accordingly follows the investment company accounting and reporting guidance of the Financial Accounting Standards Board (FASB) Accounting Standards Codification Topic 946 Financial Services - Investment Companies.
(1) Investment Valuations
Subject to its oversight, the fund's Board of Trustees has delegated primary responsibility for determining or causing to be determined the value of the fund’s investments to MFS as the fund's adviser, pursuant to the fund’s valuation policy and procedures which have been adopted by the adviser and approved by the Board. In accordance with Rule 2a-5 under the Investment Company Act of 1940, the Board of Trustees designated the adviser as the “valuation designee” of the fund. If the adviser, as valuation designee, determines that reliable market quotations are not readily available for an investment, the investment is valued at fair value as determined in good faith by the adviser in accordance with the adviser’s fair valuation policy and procedures.
Under the fund's valuation policy and procedures, debt instruments and floating rate loans, including restricted debt instruments, are generally valued at an evaluated or composite bid as provided by a third-party pricing service. Short-term instruments with a maturity at issuance of 60 days or less may be valued at amortized cost, which approximates market value. Futures contracts are generally valued at last posted settlement price on their primary exchange as provided by a third-party pricing service. Futures contracts for which there were no trades that day for a particular position are generally valued at the closing bid quotation on their primary exchange as provided by a third-party pricing service. Swap agreements are generally valued using valuations provided by a third-party pricing service, which for cleared swaps includes an evaluation of any trading activity at the clearinghouses. Open-end investment companies are generally valued at net asset value per share. The values of foreign securities and other assets and liabilities expressed in foreign currencies are converted to U.S. dollars using the mean of bid and asked prices for rates provided by a third-party pricing service.
Under the fund’s valuation policy and procedures, market quotations are not considered to be readily available for debt instruments, floating rate loans, and many types of derivatives. These investments are generally valued at fair value based on information from third-party pricing services or otherwise determined by the adviser in accordance with the adviser’s fair valuation policy and procedures. Securities and other assets generally valued on the basis of information from a third-party pricing service may also be valued at a broker/dealer bid quotation. In determining values, third-party pricing services can utilize both transaction data and market information such as yield, quality, coupon rate, maturity, type of issue, trading characteristics, spreads and other market data. Pricing services generally value debt instruments assuming orderly transactions of institutional round lot sizes, but a fund may hold or transact in such securities in smaller, odd lot sizes. In instances where a fund holds an odd lot size position in a debt instrument, such position will typically be valued using the pricing agent’s institutional round lot price for the debt instrument. Odd lots may trade at lower prices than institutional round lots, and the fund may receive different prices when it sells odd lot positions than it would receive for sales of institutional round lot positions. An investment may also be valued at fair value if the adviser determines that the investment’s value has been materially affected by events occurring after the close of the exchange or market on which the investment is principally traded (such as foreign exchange or market) and prior to the determination of the fund’s net asset value, or after the halt of trading of a specific security where trading does not resume prior to the close of the exchange or market on which the security is principally traded. The adviser generally relies on third-party pricing services or other information (such as the correlation with price movements of similar securities in the same or other markets; the type, cost and investment characteristics of the security; the business and financial condition of the issuer; and trading and other market data) to assist in determining whether to fair value and at what value to fair value an investment. The value of an investment for purposes of calculating the fund’s net asset value can differ depending on the source and method used to determine value. When fair valuation is used, the value of an investment used to determine the fund’s net asset value may differ from quoted or published prices for the same investment. There can be no assurance that the fund could obtain the fair value assigned to an investment if it were to sell the investment at the same time at which the fund determines its net asset value per share.
Various inputs are used in determining the value of the fund's assets or liabilities. These inputs are categorized into three broad levels. In certain cases, the inputs used to measure fair value may fall into different levels of the fair value hierarchy. In such cases, an investment's level within the fair value hierarchy is based on the lowest level of input that is significant to the fair value measurement. The fund's assessment of the significance of a particular input to the fair value measurement in its entirety requires judgment, and considers factors specific to the investment. Level 1 includes unadjusted quoted prices in active markets for identical assets or liabilities. Level 2 includes other significant observable market-based inputs (including quoted prices for similar securities, interest rates, prepayment speed, and credit risk).
8
Supplemental Information (unaudited) – continued
Level 3 includes significant unobservable inputs, which may include the adviser's own assumptions in determining the fair value of investments. Other financial instruments are derivative instruments, such as futures contracts and swap agreements. The following is a summary of the levels used as of May 31, 2025 in valuing the fund's assets and liabilities:
Financial Instruments Level 1 Level 2 Level 3 Total
U.S. Treasury Bonds & U.S. Government Agencies & Equivalents $— $525,496,251 $— $525,496,251
Municipal Bonds — 5,090,741 — 5,090,741
U.S. Corporate Bonds — 2,573,524 — 2,573,524
Residential Mortgage-Backed Securities — 1,177,268,618 — 1,177,268,618
Commercial Mortgage-Backed Securities — 60,091,467 — 60,091,467
Asset-Backed Securities (including CDOs) — 73,527,672 — 73,527,672
Investment Companies 88,505,301 — — 88,505,301
Total $88,505,301 $1,844,048,273 $— $1,932,553,574
Other Financial Instruments        
Futures Contracts – Assets $1,055,539 $— $— $1,055,539
Swap Agreements – Assets — 171,492 — 171,492
Swap Agreements – Liabilities — (1,715,886) — (1,715,886)
(2) Investments in Affiliated Issuers
An affiliated issuer may be considered one in which the fund owns 5% or more of the outstanding voting securities, or a company which is under common control. For the purposes of this report, the following were affiliated issuers for the period ended May 31, 2025:
Affiliated Issuers Beginning
Value 		Purchases Sales
Proceeds 		Realized
Gain
(Loss) 		Change in
Unrealized
Appreciation or
Depreciation 		Ending
Value
MFS Institutional Money Market Portfolio $24,511,411 $380,733,112 $316,720,900 $(18,322) $— $88,505,301
Affiliated Issuers Dividend
Income 		Capital Gain
Distributions
MFS Institutional Money Market Portfolio $1,114,296 $—
9