N-MFP2 0000798244 XXXXXXXX 2017-08-31 0000798244 CQT3VZHUKW04X1YLM325 S000000762 10 N N 033-07638 Massachusetts Financial Services Company 801-17352 Deloitte & Touche LLP Boston MA Massachusetts Financial Services Company MFS Service Center, Inc 0000769188 084-01316 N N N Exempt Government N 31 31 49779271.66 77841210.00 96399786.84 95874627.13 252699442.34 250016193.10 262608692.86 283109389.71 0.00 0.1776 0.2756 0.3402 0.3385 0.9014 0.8850 0.9268 0.9997 0.0000 85.93 282080140.74 282079576.91 63650.50 398316.52 281744996.82 281975004.1740 1.0000 0.0100 0.9992 0.9992 0.9992 0.9992 0.0000 C000002179 1000.00 105909920.85 105994510.7740 0.9992 0.9992 0.9992 0.9992 0.0000 667301.43 1867023.22 503430.14 607095.53 191168.35 747768.41 791144.94 498974.76 0.00 0.00 2236191.54 4768171.40 0.0030 Y For Class A during the period, MFS waived: $716 management fees; MFD waived: $22,615 12b-1 fees. C000002180 250.00 347440.23 347780.3230 0.9990 0.9990 0.9990 0.9990 0.0000 774.99 3264.09 7505.00 7983.40 1353.00 0.00 0.00 3813.37 0.00 0.00 9632.99 15060.86 0.0025 Y For Class 529B during the period, MFS waived: $2 management fees; MFD waived: $296 12b-1 fees, $15 program manager fees. C000002181 250.00 6973290.94 6978523.0100 0.9992 0.9992 0.9992 0.9992 0.0000 64241.34 177317.45 178122.49 70799.45 133264.09 307390.14 18556.66 129917.35 0.00 0.00 381305.08 706456.45 0.0025 Y For Class 529C during the period, MFS waived: $48 management fees; MFD waived: $6,069 12b-1 fees, $303 program manager fees. C000002182 1000.00 17390966.04 17407828.3330 0.9990 0.9990 0.9990 0.9990 0.0000 21064.72 195593.45 145022.15 120599.88 368169.73 225161.63 58842.67 188990.23 0.00 0.00 676726.44 809646.97 0.0030 Y For Class B during the period, MFS waived: $117 management fees; MFD waived: $14,806 12b-1 fees. C000002183 1000.00 38550215.03 38581419.7200 0.9992 0.9992 0.9992 0.9992 0.0000 181614.24 481192.57 374547.40 220639.75 577454.27 187431.63 288104.19 259029.00 0.00 0.00 1427606.97 1412927.50 0.0030 Y For Class C during the period, MFS waived: $259 management fees; MFD waived: $32,739 12b-1 fees. C000002184 1.00 12375351.65 12385546.5750 0.9992 0.9992 0.9993 0.9993 0.0000 66814.99 8.31 1072857.04 708.43 726344.29 46312.63 109160.24 52048.10 0.00 0.00 1972519.02 195749.96 0.0030 Y For Class R1 during the period, MFS waived: $80 management fees; MFD waived: $10,126 12b-1 fees. C000002186 1.00 48155177.92 48194460.5120 0.9992 0.9992 0.9992 0.9992 0.0000 71292.27 34775.02 387602.46 419860.06 120780.62 231446.27 102456.81 15821.63 0.00 0.00 760865.94 1006228.58 0.0030 Y For Class R2 during the period, MFS waived: $324 management fees; MFD waived: $20,524 12b-1 fees. C000002187 1.00 35592911.77 35622807.9600 0.9992 0.9992 0.9992 0.9992 0.0000 49694.31 12789.50 1154831.29 364.95 386697.77 2504.39 40483.16 327692.85 0.00 0.00 1737879.36 343367.82 0.0030 Y For Class R3 during the period, MFS waived: $237 management fees; MFD waived: $7,475 12b-1 fees. C000002188 1.00 3248574.47 3251139.7740 0.9992 0.9992 0.9992 0.9992 0.0000 8625.27 606.90 0.00 0.15 7826.12 19070.75 260.31 1279.68 0.00 0.00 23245.06 20962.53 0.0030 Y For Class R4 during the period, MFS waived: $22 management fees. C000002189 250.00 13201147.92 13210987.1930 0.9993 0.9992 0.9992 0.9992 0.0000 124734.67 193716.65 164081.64 348484.00 160104.37 109862.57 61928.36 136836.92 0.00 0.00 534429.89 897674.63 0.0025 Y For Class 529A during the period, MFS waived: $90 management fees; MFD waived: $2,839 12b-1 fees, $568 program manager fees. Federal Farm Credit Bank Federal Farm Credit Bank 313313LD8 US313313LD84 U.S. Government Agency Debt Y 2017-09-01 2017-09-01 2017-09-01 N N N 0.0001 1000000.00 1000000.00 0.0035 N Y Y N Federal Farm Credit Bank Federal Farm Credit Bank 313313LR7 US313313LR70 U.S. Government Agency Debt Y 2017-09-13 2017-09-13 2017-09-13 N N N 0.0101 2499167.50 2499167.50 0.0089 N N Y N Federal Farm Credit Bank Federal Farm Credit Bank 313313LX4 US313313LX49 U.S. Government Agency Debt Y 2017-09-19 2017-09-19 2017-09-19 N N N 0.0101 7996000.00 7996000.00 0.0284 N N Y N Federal Farm Credit Bank Federal Farm Credit Bank 313313LZ9 US313313LZ96 U.S. Government Agency Debt Y 2017-09-21 2017-09-21 2017-09-21 N N N 0.0101 3198220.80 3198220.80 0.0114 N N Y N Federal Farm Credit Bank Federal Farm Credit Bank 313313ML9 US313313ML91 U.S. Government Agency Debt Y 2017-10-02 2017-10-02 2017-10-02 N N N 0.0102 3996520.00 3996520.00 0.0142 N N Y N Federal Farm Credit Bank Federal Farm Credit Bank 313313MM7 US313313MM74 U.S. Government Agency Debt Y 2017-10-03 2017-10-03 2017-10-03 N N N 0.0102 9991020.00 9991020.00 0.0355 N N Y N Federal Farm Credit Bank Federal Farm Credit Bank 313313MW5 US313313MW56 U.S. Government Agency Debt Y 2017-10-12 2017-10-12 2017-10-12 N N N 0.0103 4494825.00 4494825.00 0.0160 N N Y N Federal Farm Credit Bank Federal Farm Credit Bank 313313NA2 US313313NA28 U.S. Government Agency Debt Y 2017-10-16 2017-10-16 2017-10-16 N N N 0.0103 7091032.70 7091032.70 0.0252 N N Y N Federal Farm Credit Bank Federal Farm Credit Bank 313313NE4 US313313NE40 U.S. Government Agency Debt Y 2017-10-20 2017-10-20 2017-10-20 N N N 0.0103 11409290.63 11409290.63 0.0405 N N Y N Federal Farm Credit Bank Federal Farm Credit Bank 313313PH5 US313313PH52 U.S. Government Agency Debt Y 2017-11-16 2017-11-16 2017-11-16 N N N 0.0104 4989235.00 4989235.00 0.0177 N N N N Federal Home Loan Bank Federal Home Loan Bank 313385LH7 US313385LH75 U.S. Government Agency Debt Y 2017-09-05 2017-09-05 2017-09-05 N N N 0.0101 15175315.35 15175315.35 0.0539 N N Y N Federal Home Loan Bank Federal Home Loan Bank 313385LL8 US313385LL87 U.S. Government Agency Debt Y 2017-09-08 2017-09-08 2017-09-08 N N N 0.0101 1611687.27 1611687.27 0.0057 N N Y N Federal Home Loan Bank Federal Home Loan Bank 313385LP9 US313385LP91 U.S. Government Agency Debt Y 2017-09-11 2017-09-11 2017-09-11 N N N 0.0101 3998888.00 3998888.00 0.0142 N N Y N Federal Home Loan Bank Federal Home Loan Bank 313385LR5 US313385LR57 U.S. Government Agency Debt Y 2017-09-13 2017-09-13 2017-09-13 N N N 0.0101 6888705.30 6888705.30 0.0245 N N Y N Federal Home Loan Bank Federal Home Loan Bank 313385MD5 US313385MD52 U.S. Government Agency Debt Y 2017-09-25 2017-09-25 2017-09-25 N N N 0.0101 11292462.90 11292462.90 0.0401 N N Y N Federal Home Loan Bank Federal Home Loan Bank 313385ME3 US313385ME36 U.S. Government Agency Debt Y 2017-09-26 2017-09-26 2017-09-26 N N N 0.0101 7748618.72 7748618.72 0.0275 N N Y N Federal Home Loan Bank Federal Home Loan Bank 313385MF0 US313385MF01 U.S. Government Agency Debt Y 2017-09-27 2017-09-27 2017-09-27 N N N 0.0102 6895018.20 6895018.20 0.0245 N N Y N Federal Home Loan Bank Federal Home Loan Bank 313385MQ6 US313385MQ65 U.S. Government Agency Debt Y 2017-10-06 2017-10-06 2017-10-06 N N N 0.0103 2657387.88 2657387.88 0.0094 N N Y N Federal Home Loan Mortgage Corp. Federal Home Loan Mortgage Corp. 313397LL3 S6XOOCT0IEG5ABCC6L87 US313397LL34 U.S. Government Agency Debt Y 2017-09-08 2017-09-08 2017-09-08 N N N 0.0101 11547759.30 11547759.30 0.0410 N N Y N Federal Home Loan Mortgage Corp. Federal Home Loan Mortgage Corp. 313397LP4 S6XOOCT0IEG5ABCC6L87 US313397LP48 U.S. Government Agency Debt Y 2017-09-11 2017-09-11 2017-09-11 N N N 0.0101 5653427.91 5653427.91 0.0201 N N Y N Federal Home Loan Mortgage Corp. Federal Home Loan Mortgage Corp. 313397LS8 S6XOOCT0IEG5ABCC6L87 US313397LS86 U.S. Government Agency Debt Y 2017-09-14 2017-09-14 2017-09-14 N N N 0.0101 2998917.00 2998917.00 0.0106 N N Y N Federal Home Loan Mortgage Corp. Federal Home Loan Mortgage Corp. 313397LZ2 S6XOOCT0IEG5ABCC6L87 US313397LZ20 U.S. Government Agency Debt Y 2017-09-21 2017-09-21 2017-09-21 N N N 0.0101 13466508.46 13466508.46 0.0478 N N Y N Federal Home Loan Mortgage Corp. Federal Home Loan Mortgage Corp. 313397MD0 S6XOOCT0IEG5ABCC6L87 US313397MD09 U.S. Government Agency Debt Y 2017-09-25 2017-09-25 2017-09-25 N N N 0.0101 1848766.05 1848766.05 0.0066 N N Y N Federal Home Loan Mortgage Corp. Federal Home Loan Mortgage Corp. 313397MP3 S6XOOCT0IEG5ABCC6L87 US313397MP39 U.S. Government Agency Debt Y 2017-10-05 2017-10-05 2017-10-05 N N N 0.0103 8991414.00 8991414.00 0.0319 N N Y N Federal Home Loan Mortgage Corp. Federal Home Loan Mortgage Corp. 313397NB3 S6XOOCT0IEG5ABCC6L87 US313397NB34 U.S. Government Agency Debt Y 2017-10-17 2017-10-17 2017-10-17 N N N 0.0103 6941027.55 6941027.55 0.0246 N N Y N Federal Home Loan Mortgage Corp. Federal Home Loan Mortgage Corp. 313397NE7 S6XOOCT0IEG5ABCC6L87 US313397NE72 U.S. Government Agency Debt Y 2017-10-20 2017-10-20 2017-10-20 N N N 0.0103 4993125.00 4993125.00 0.0177 N N Y N Federal National Mortgage Assoc. Federal National Mortgage Assoc. 313589LD3 B1V7KEBTPIMZEU4LTD58 US313589LD32 U.S. Government Agency Debt Y 2017-09-01 2017-09-01 2017-09-01 N N N 0.0001 1385000.00 1385000.00 0.0049 N Y Y N Federal National Mortgage Assoc. Federal National Mortgage Assoc. 313589LH4 B1V7KEBTPIMZEU4LTD58 US313589LH46 U.S. Government Agency Debt Y 2017-09-05 2017-09-05 2017-09-05 N N N 0.0101 11560716.62 11560716.62 0.0410 N N Y N Federal National Mortgage Assoc. Federal National Mortgage Assoc. 313589LJ0 B1V7KEBTPIMZEU4LTD58 US313589LJ02 U.S. Government Agency Debt Y 2017-09-06 2017-09-06 2017-09-06 N N N 0.0101 4749339.75 4749339.75 0.0169 N N Y N Federal National Mortgage Assoc. Federal National Mortgage Assoc. 313589ML4 B1V7KEBTPIMZEU4LTD58 US313589ML49 U.S. Government Agency Debt Y 2017-10-02 2017-10-02 2017-10-02 N N N 0.0102 20808880.51 20808880.51 0.0739 N N Y N Federal National Mortgage Assoc. Federal National Mortgage Assoc. 313589MM2 B1V7KEBTPIMZEU4LTD58 US313589MM22 U.S. Government Agency Debt Y 2017-10-03 2017-10-03 2017-10-03 N N N 0.0102 3996408.00 3996408.00 0.0142 N N Y N Federal National Mortgage Assoc. Federal National Mortgage Assoc. 313589NC3 B1V7KEBTPIMZEU4LTD58 US313589NC31 U.S. Government Agency Debt Y 2017-10-18 2017-10-18 2017-10-18 N N N 0.0103 9287733.30 9287733.30 0.0330 N N Y N Federal National Mortgage Assoc. Federal National Mortgage Assoc. 313589NK5 B1V7KEBTPIMZEU4LTD58 US313589NK56 U.S. Government Agency Debt Y 2017-10-25 2017-10-25 2017-10-25 N N N 0.0101 4393334.00 4393334.00 0.0156 N N Y N Goldman Sachs Group, Inc. (The) Goldman Sachs & Co. 1.050000% FOR8UP27PHTHYVLBNG30 0000769993 318991007_1.05_0901 U.S. Government Agency Repurchase Agreement, collateralized only by U.S. Government Agency securities, U.S. Treasuries, and cash Y N U.S. Treasury Bill N.A. 2017-09-14 0.00 100.00 99.96 U.S. Treasuries (including strips) FNMA 2020-02-28 1.500000 2291000.00 2291878.22 Agency Debentures and Agency Strips FMAC 2032-07-15 6.250000 94000.00 135546.36 Agency Debentures and Agency Strips USTR 2021-05-15 8.125000 100.00 125.92 U.S. Treasuries (including strips) USTR 2022-11-15 7.625000 600.00 787.80 U.S. Treasuries (including strips) USTR 2046-08-15 2.250000 11200000.00 10078300.52 U.S. Treasuries (including strips) USTR 2019-06-30 1.625000 500.00 504.08 U.S. Treasuries (including strips) Y 2017-09-01 2017-09-01 2017-09-01 N N N 0.0105 12262000.00 12262000.00 0.0435 N Y Y N U.S. Treasury Bill U.S. Treasury Bill 912796KL2 N.A. US912796KL23 U.S. Treasury Debt Y 2017-09-14 2017-09-14 2017-09-14 N N N 0.0090 12492017.77 12492017.77 0.0443 N Y Y N U.S. Treasury Bill U.S. Treasury Bill 912796LT4 N.A. US912796LT40 U.S. Treasury Debt Y 2017-09-07 2017-09-07 2017-09-07 N N N 0.0089 9798561.56 9798561.56 0.0348 N Y Y N U.S. Treasury Bill U.S. Treasury Bill 912796LY3 N.A. US912796LY35 U.S. Treasury Debt Y 2017-10-19 2017-10-19 2017-10-19 N N N 0.0113 11572769.49 11572769.49 0.0411 N Y Y N U.S. Treasury Bill U.S. Treasury Bill 912796NS4 N.A. US912796NS49 U.S. Treasury Debt Y 2018-02-15 2018-02-15 2018-02-15 N N N 0.0107 10399039.22 10399039.22 0.0369 N Y Y N MFS Series Trust I 2017-09-07 /S/Kino Clark Kino Clark Assistant Treasurer