IAB-Q3
 
Quarterly Report
July 31, 2026
MFS®  Inflation-Adjusted
Bond Fund  
 
Portfolio of Investments
7/31/26 (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 – 99.9%
Asset-Backed & Securitized – 3.2%
3650R Commercial Mortgage Trust, 2021-PF1, “XA”, 0.985%, 11/15/2054 (i)
 
$
14,310,326
$434,776
AREIT 2022-CRE6 Trust, “AS”, FLR, 5.271% (SOFR - 30 day + 1.65%), 1/20/2037 (n)
 
 
2,462,500
2,459,017
Babson CLO Ltd., 2021-3A, “B1R”, FLR, 5.359% (SOFR - 3mo. + 1.63%), 1/18/2035 (n)
 
 
3,000,000
3,004,521
BBCMS Mortgage Trust, 2021-C10, “XA”, 1.19%, 7/15/2054 (i)
 
 
11,473,693
507,401
BBCMS Mortgage Trust, 2021-C9, “XA”, 1.538%, 2/15/2054 (i)
 
 
7,591,144
418,964
Benchmark 2021-B23 Mortgage Trust, “XA”, 1.244%, 2/15/2054 (i)
 
 
24,610,569
986,822
Benchmark 2021-B24 Mortgage Trust, “XA”, 1.073%, 3/15/2054 (i)
 
 
14,262,694
488,921
Benchmark 2021-B27 Mortgage Trust, “XA”, 1.343%, 7/15/2054 (i)
 
 
19,966,971
827,224
Benchmark 2021-B28 Mortgage Trust, “XA”, 1.215%, 8/15/2054 (i)
 
 
24,030,508
1,040,877
BX Trust, 2026-CLS, “A”, 5.076%, 5/15/2043 (n)
 
 
3,035,000
3,040,695
Commercial Mortgage Pass-Through Certificates, 2021-BN31, “XA”, 1.278%, 2/15/2054 (i)
 
 
18,724,393
826,128
JPMorgan Mortgage Trust, 2026-NQM1, “A1”, 4.745%, 6/25/2066 (n)
 
 
1,183,595
1,165,502
Morgan Stanley Capital I Trust, 2021-L5, “XA”, 1.176%, 5/15/2054 (i)
 
 
8,916,612
377,553
Morgan Stanley Capital I Trust, 2021-L6, “XA”, 1.14%, 6/15/2054 (i)
 
 
10,470,670
369,115
Morgan Stanley Capital I Trust, 2021-L7, “XA”, 1.057%, 10/15/2054 (i)
 
 
25,866,353
889,363
Morgan Stanley Residential Mortgage Loan Trust, 2025-NQM3, “A1”, 5.53%, 5/25/2070 (n)
 
 
1,124,149
1,120,885
New Residential Mortgage Loan Trust, 2026-NQM2, “A1”, 4.743%, 12/25/2065 (n)
 
 
3,639,014
3,574,117
OBX Trust, 2025-NQM8, “A1”, 5.472%, 3/25/2065 (n)
 
 
757,848
756,038
Palmer Square Loan Funding, 2024-3A Ltd., “A2R”, FLR, 4.8% (SOFR - 3mo. + 1.15%), 8/08/2032 (n)
 
 
969,388
968,392
Palmer Square Loan Funding, 2025-1A Ltd., “A2”, FLR, 4.851% (SOFR - 3mo. + 1.2%), 2/15/2033 (n)
 
 
4,300,000
4,297,768
Palmer Square Loan Funding, 2025-2A Ltd., “A2”, FLR, 5.152% (SOFR - 3mo. + 1.4%), 7/15/2033 (n)
 
 
5,700,000
5,700,878
PMT Loan Trust, 2025-INV10, “A36”, FLR, 4.966% (SOFR - 1mo. + 1.35%), 10/01/2056 (n)
 
 
1,444,512
1,444,840
PMT Loan Trust, 2026-CNF1, “A26”, FLR, 4.816% (SOFR - 1mo. + 1.2%), 1/25/2057 (n)
 
 
1,355,757
1,352,750
PMT Loan Trust, 2026-INV2, “A35”, FLR, 4.766% (SOFR - 1mo. + 1.15%), 1/25/2057 (n)
 
 
7,346,981
7,290,106
Shackleton 2019-14A CLO Ltd., “BRR”, FLR, 5.279% (SOFR - 3mo. + 1.55%), 7/20/2034 (n)
 
 
3,996,016
3,996,735
Wells Fargo Commercial Mortgage Trust, 2021-C60, “XA”, 1.507%, 8/15/2054 (i)
 
 
8,322,484
482,817
 
 
 
$47,822,205
Consumer Services – 0.1%
Conservation Fund, 3.474%, 12/15/2029 
 
$
1,438,000
$1,358,364
Medical & Health Technology & Services – 0.2%
ProMedica Toledo Hospital, “B”, AGM, 5.325%, 11/15/2028 
 
$
2,421,000
$2,439,865
Mortgage-Backed – 6.2%
Fannie Mae, 4.5%, 3/15/2048 (i)
 
$
964,608
$222,258
Fannie Mae, 2%, 9/25/2050 (i)
 
 
980,683
128,532
Fannie Mae, 4%, 9/25/2050 (i)
 
 
1,948,011
371,797
Fannie Mae, 2.5%, 2/25/2051 (i)
 
 
1,354,941
183,468
Fannie Mae, 5.066%, 11/25/2053 
 
 
1,427,827
1,459,025
Fannie Mae, 5.616%, 11/25/2053 
 
 
3,254,151
3,363,889
Fannie Mae, 4.616%, 12/25/2054 
 
 
2,816,577
2,836,228
Fannie Mae, 5.016%, 12/25/2054 
 
 
922,952
934,460
Fannie Mae, 5.116%, 12/25/2054 
 
 
2,003,888
2,023,445
Fannie Mae, 4.916%, 1/25/2055 
 
 
3,871,728
3,908,198
Freddie Mac, 0.414%, 5/25/2029 (i)
 
 
25,340,874
275,400
Freddie Mac, 0.816%, 7/25/2029 (i)
 
 
28,847,080
647,132
Freddie Mac, 0.569%, 1/25/2030 (i)
 
 
7,337,985
132,070
Freddie Mac, 1.312%, 1/25/2030 (i)
 
 
13,280,343
521,487
Freddie Mac, 1.796%, 4/25/2030 (i)
 
 
3,519,182
210,358
Freddie Mac, 1.665%, 5/25/2030 (i)
 
 
6,326,494
367,547
Freddie Mac, 1.364%, 6/25/2030 (i)
 
 
9,559,072
412,954
Freddie Mac, 1.167%, 9/25/2030 (i)
 
 
3,529,812
151,393
Freddie Mac, 0.709%, 12/25/2030 (i)
 
 
1,816,180
47,562
Freddie Mac, 0.314%, 1/25/2031 (i)
 
 
29,303,232
313,814
Freddie Mac, 0.535%, 1/25/2031 (i)
 
 
54,980,294
1,213,129
1
Portfolio of Investments (unaudited) – continued
Issuer
 
 
Shares/Par
Value ($)
Bonds – continued
Mortgage-Backed – continued
Freddie Mac, 0.778%, 1/25/2031 (i)
 
$
11,388,256
$364,943
Freddie Mac, 0.934%, 1/25/2031 (i)
 
 
8,529,316
312,857
Freddie Mac, 0.504%, 3/25/2031 (i)
 
 
35,862,483
679,730
Freddie Mac, 1.212%, 5/25/2031 (i)
 
 
4,421,663
223,520
Freddie Mac, 0.938%, 7/25/2031 (i)
 
 
7,521,262
315,814
Freddie Mac, 0.536%, 9/25/2031 (i)
 
 
32,486,236
788,798
Freddie Mac, 0.854%, 9/25/2031 (i)
 
 
9,783,880
372,482
Freddie Mac, 0.348%, 11/25/2031 (i)
 
 
49,721,062
818,573
Freddie Mac, 0.495%, 12/25/2031 (i)
 
 
50,485,813
1,141,449
Freddie Mac, 0.566%, 12/25/2031 (i)
 
 
8,215,224
208,533
Freddie Mac, 0.265%, 5/25/2033 (i)
 
 
29,100,000
548,648
Freddie Mac, 0.905%, 9/25/2034 (i)
 
 
7,419,164
472,178
Freddie Mac, 0.246%, 1/25/2035 (i)
 
 
35,704,535
749,752
Freddie Mac, 2.5%, 11/25/2050 - 3/25/2051 (i)
 
 
4,825,901
780,645
Freddie Mac, 2%, 3/25/2051 - 3/25/2052 (i)
 
 
7,852,678
1,003,547
Freddie Mac, 3%, 10/25/2052 (i)
 
 
881,009
141,722
Freddie Mac, 5.616%, 11/25/2053 
 
 
3,603,705
3,688,023
Freddie Mac, 4.916%, 3/25/2054 
 
 
2,738,636
2,768,218
Freddie Mac, 4.716%, 9/25/2054 
 
 
1,682,751
1,695,056
Freddie Mac, 4.566%, 2/25/2055 
 
 
3,389,916
3,411,681
Freddie Mac, 2.36%, 8/15/2057 (i)
 
 
1,084,507
119,119
Ginnie Mae, 2.415%, 7/20/2050 (i)
 
 
2,375,420
258,285
Ginnie Mae, 2.5%, 10/20/2050 (i)
 
 
2,265,994
343,708
Ginnie Mae, 2.578%, 5/20/2051 (i)
 
 
1,687,694
200,418
Ginnie Mae, 2.515%, 6/20/2051 (i)
 
 
3,272,508
374,238
Ginnie Mae, 2.378%, 7/20/2051 (i)
 
 
890,969
91,968
Ginnie Mae, 4.921%, 10/20/2053 
 
 
6,483,644
6,566,377
Ginnie Mae, 4.971%, 10/20/2053 
 
 
6,300,824
6,389,879
Ginnie Mae, 4.721%, 11/20/2053 
 
 
5,338,355
5,400,414
Ginnie Mae, 4.821%, 12/20/2053 
 
 
6,319,485
6,383,007
Ginnie Mae, 4.571%, 3/20/2054 
 
 
5,938,994
5,955,115
Ginnie Mae, 4.771%, 6/20/2054 
 
 
2,742,278
2,753,318
Ginnie Mae, 4.671%, 10/20/2054 
 
 
1,437,493
1,443,249
Ginnie Mae, 5.121%, 5/20/2055 
 
 
1,367,801
1,388,194
Ginnie Mae, 7.571%, 5/20/2055 
 
 
952,370
967,456
Ginnie Mae, 6.142%, 6/20/2055 
 
 
2,440,672
2,347,156
Ginnie Mae, 6.217%, 6/20/2055 
 
 
1,218,543
1,159,550
Ginnie Mae, 4.621%, 12/20/2064 
 
 
1,628,014
1,635,371
Ginnie Mae, 4.421%, 8/20/2065 
 
 
2,521,024
2,520,386
Ginnie Mae, 4.54%, 1/20/2067 
 
 
860,616
864,361
Ginnie Mae, 4.071%, 5/20/2067 
 
 
2,448,303
2,442,339
Ginnie Mae, 4.121%, 8/20/2067 
 
 
1,533,323
1,529,886
Ginnie Mae, 4.271%, 8/20/2074 
 
 
1,030,324
1,032,372
 
 
 
$92,376,481
Municipals – 0.0%
Colorado Health Facilities Authority Rev., Taxable (Covenant Living Communities and Services), “B”, 2.8%, 12/01/2026 
 
$
380,000
$376,926
U.S. Treasury Inflation Protected Securities – 90.2%
U.S. Treasury Bonds, 3.625%, 4/15/2028 
 
$
55,746,675
$56,803,799
U.S. Treasury Bonds, 1.125%, 1/15/2033 
 
 
79,694,183
74,518,400
U.S. Treasury Bonds, 0.75%, 2/15/2042 
 
 
109,735,359
80,514,632
U.S. Treasury Bonds, 0.625%, 2/15/2043 
 
 
38,497,230
26,879,667
U.S. Treasury Bonds, 0.75%, 2/15/2045 
 
 
56,508,719
38,295,468
U.S. Treasury Bonds, 1%, 2/15/2048 
 
 
26,283,858
17,757,515
U.S. Treasury Bonds, 0.125%, 2/15/2052 
 
 
43,635,793
21,128,949
U.S. Treasury Bonds, 2.125%, 2/15/2054 
 
 
44,760,792
37,018,065
U.S. Treasury Bonds, 2.375%, 2/15/2056 
 
 
5,548,098
4,843,214
U.S. Treasury Notes, 0.5%, 1/15/2028 
 
 
5,672,303
5,513,331
2
Portfolio of Investments (unaudited) – continued
Issuer
 
 
Shares/Par
Value ($)
Bonds – continued
U.S. Treasury Inflation Protected Securities – continued
U.S. Treasury Notes, 0.875%, 1/15/2029 (f)
 
$
117,800,416
$114,068,777
U.S. Treasury Notes, 0.125%, 1/15/2030 
 
 
12,686,520
11,847,383
U.S. Treasury Notes, 1.625%, 4/15/2030 
 
 
59,646,624
58,482,303
U.S. Treasury Notes, 0.125%, 7/15/2030 
 
 
154,017,091
142,971,255
U.S. Treasury Notes, 1.125%, 10/15/2030 
 
 
64,219,600
61,850,244
U.S. Treasury Notes, 0.125%, 1/15/2031 
 
 
183,133,465
167,873,893
U.S. Treasury Notes, 0.125%, 1/15/2032 (f)
 
 
108,395,459
97,209,802
U.S. Treasury Notes, 0.625%, 7/15/2032 
 
 
12,108,180
11,102,037
U.S. Treasury Notes, 1.375%, 7/15/2033 
 
 
72,370,367
68,530,463
U.S. Treasury Notes, 1.75%, 1/15/2034 
 
 
137,450,667
132,457,393
U.S. Treasury Notes, 1.875%, 7/15/2034 
 
 
41,696,419
40,471,376
U.S. Treasury Notes, 1.875%, 1/15/2036 
 
 
76,927,223
73,287,436
 
 
 
$1,343,425,402
Total Bonds
$1,487,799,243
Mutual Funds (h) – 0.5%
Money Market Funds – 0.5%
MFS Institutional Money Market Portfolio, 3.73% (v)
 
 
7,543,903
$7,545,412
 
Other Assets, Less Liabilities – (0.4)%
(5,531,684
)
Net Assets – 100.0%
$1,489,812,971
 
(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 $7,545,412 and
$1,487,799,243, 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 $40,172,244,
representing 2.7% 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
 
Derivative Contracts at 7/31/26
Futures Contracts
Description
Long/
Short
Currency
Contracts
Notional
Amount
Expiration
Date
Value/Unrealized
Appreciation
(Depreciation)
Liability Derivatives
Interest Rate Futures 
U.S. Treasury Note 5 yr
Long
USD
371
$39,317,305
September – 2026
$(154,927
)
 
3
Portfolio of Investments (unaudited) – continued
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 
4/30/29
USD
75,740,000
centrally cleared
1-day SOFR / Annually
3.637% / Annually
$963,034
$—
$963,034
1/14/31
USD
46,157,000
centrally cleared
1-day SOFR / Annually
3.511% / Annually
1,167,348
—
1,167,348
 
 
 
 
 
 
$2,130,382
$—
$2,130,382
Inflation Swaps 
2/05/27
USD
80,400,000
centrally cleared
CPI-U / At Maturity
2.755% / At Maturity
$455,260
$—
$455,260
3/20/27
USD
76,800,000
centrally cleared
CPI-U / At Maturity
3.291% / At Maturity
73,426
—
73,426
 
 
 
 
 
 
$528,686
$—
$528,686
 
 
 
 
 
 
$2,659,068
$—
$2,659,068
Liability Derivatives
Inflation Swaps 
10/14/26
USD
84,400,000
centrally cleared
3.17% / At Maturity
CPI-U / At Maturity
$(213,661
)
$—
$(213,661
)
5/14/27
USD
37,860,000
centrally cleared
CPI-U / At Maturity
3.487% / At Maturity
(150,156
)
—
(150,156
)
7/13/27
USD
22,561,000
centrally cleared
CPI-U / At Maturity
2.151% / At Maturity
(349,745
)
—
(349,745
)
5/21/46
USD
11,609,000
centrally cleared
CPI-U / At Maturity
2.519% / At Maturity
(120,020
)
—
(120,020
)
5/20/56
USD
14,960,000
centrally cleared
CPI-U / At Maturity
2.463% / At Maturity
(160,700
)
—
(160,700
)
 
 
 
 
 
 
$(994,282
)
$—
$(994,282
)
At July 31, 2026, the fund had liquid securities collateral with an aggregate value of $5,905,700 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.
4
Supplemental Information
7/31/26 (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).
5
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 July 31, 2026 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
$—
$1,343,425,402
$—
$1,343,425,402
Municipal Bonds
—
376,926
—
376,926
U.S. Corporate Bonds
—
3,798,229
—
3,798,229
Residential Mortgage-Backed Securities
—
109,080,719
—
109,080,719
Commercial Mortgage-Backed Securities
—
13,149,673
—
13,149,673
Asset-Backed Securities (including CDOs)
—
17,968,294
—
17,968,294
Investment Companies
7,545,412
—
—
7,545,412
Total
$7,545,412
$1,487,799,243
$—
$1,495,344,655
Other Financial Instruments
Futures Contracts – Liabilities
$(154,927
)
$—
$—
$(154,927
)
Swap Agreements – Assets
—
2,659,068
—
2,659,068
Swap Agreements – Liabilities
—
(994,282
)
—
(994,282
)
For further information regarding security characteristics, see the Portfolio of Investments.
(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. The following were affiliated issuers for the period ended July 31, 2026:
 
Affiliated Issuers
Beginning
Value
Purchases
Sales
Proceeds
Realized
Gain
(Loss)
Change in
Unrealized
Appreciation or
Depreciation
Ending
Value
MFS Institutional Money Market Portfolio
$39,079,284
$204,993,714
$236,520,010
$(6,597
)
$(979
)
$7,545,412
 
Affiliated Issuers
Dividend
Income
Capital Gain
Distributions
MFS Institutional Money Market Portfolio
$393,562
$—
6