N-MFP2 0000798244 XXXXXXXX 2019-01-31 0000798244 CQT3VZHUKW04X1YLM325 S000000762 12 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 29 29 52531079.66 42487337.64 44486069.57 31880487.72 236890117.14 235807947.34 232172901.15 195784286.61 0.00 0.2214 0.1802 0.1915 0.1397 0.9983 0.9999 0.9994 0.8579 0.0000 609.74 225494329.09 225501759.80 158685.16 514821.20 225146233.50 225376241.5300 1.0000 0.0239 0.9990 0.9990 0.9990 0.9990 0.0000 C000002179 1000.00 105138537.20 105246695.0090 0.9990 0.9990 0.9990 0.9990 0.0000 3511454.82 1350960.86 791689.41 1640851.18 435223.24 3612557.86 920048.78 4250078.18 0.00 0.00 4753665.04 12811932.21 0.0168 Y For Class A during the period, MFS waived: $938 management fees; MFD waived: $23,594 12b-1 fees. C000002180 250.00 234615.43 234851.6210 0.9989 0.9988 0.9988 0.9990 0.0000 623.21 0.00 5.00 28345.15 400.00 11728.07 46.73 3250.51 0.00 0.00 5182.06 46823.73 0.0163 Y For Class 529B during the period, MFS waived: $2 management fees; MFD waived: $210 12b-1 fees. C000002181 250.00 6422478.05 6429024.6520 0.9990 0.9990 0.9990 0.9990 0.0000 52543.67 72516.32 264531.81 133052.22 45478.91 118351.05 55199.07 120036.59 0.00 0.00 406959.06 476731.35 0.0163 Y For Class 529C during the period, MFS waived: $55 management fees; MFD waived: $5,531 12b-1 fees. C000002182 1000.00 11283996.94 11295459.6050 0.9990 0.9990 0.9990 0.9990 0.0000 292827.61 165013.12 144585.69 138563.65 105997.91 158319.23 103445.09 280515.58 0.00 0.00 542556.21 852009.81 0.0168 Y For Class B during the period, MFS waived: $97 management fees; MFD waived: $9,764 12b-1 fees. C000002183 1000.00 21933209.75 21955524.7860 0.9990 0.9990 0.9990 0.9990 0.0000 464828.41 301911.29 561223.22 610400.92 310592.37 406451.16 17201.33 593351.84 0.00 0.00 1506058.82 2331368.15 0.0168 Y For Class C during the period, MFS waived: $191 management fees; MFD waived: $19,184 12b-1 fees. C000002184 1.00 8397182.66 8405616.4180 0.9990 0.9990 0.9990 0.9990 0.0000 25044.80 5.27 23496.63 1917.20 64577.07 66835.13 10531.27 0.00 0.00 0.00 175393.42 76334.11 0.0168 Y For Class R1 during the period, MFS waived: $71 management fees; MFD waived: $7,082 12b-1 fees. C000002186 1.00 35256446.92 35292503.4370 0.9990 0.9990 0.9990 0.9990 0.0000 305108.92 190757.14 25815.01 195817.62 126823.66 340726.86 33239.25 152102.36 0.00 0.00 590210.94 1446951.60 0.0168 Y For Class R2 during the period, MFS waived: $303 management fees; MFD waived: $15,232 12b-1 fees. C000002187 1.00 17118943.24 17136234.8740 0.9987 0.9987 0.9987 0.9990 0.0000 208589.69 314603.96 599.13 542585.83 42391.62 80000.20 33966.12 54022.91 0.00 0.00 299336.46 1007394.69 0.0168 Y For Class R3 during the period, MFS waived: $146 management fees; MFD waived: $3,677 12b-1 fees. C000002188 1.00 2743918.85 2746690.6740 0.9990 0.9990 0.9990 0.9990 0.0000 3723.69 797.00 0.00 0.09 967.42 814.03 0.00 57.32 0.00 0.00 4633.79 822.78 0.0168 Y For Class R4 during the period, MFS waived: $23 management fees. C000002189 250.00 16516565.43 16533200.0640 0.9990 0.9990 0.9990 0.9990 0.0000 166740.18 519438.46 199239.81 345930.25 231301.41 143467.86 216804.73 111490.26 0.00 0.00 948133.11 1148290.37 0.0163 Y For Class 529A during the period, MFS waived: $138 management fees; MFD waived: $3,486 12b-1 fees. C000206004 1.00 50174.96 50225.6500 0.9990 0.9990 0.9990 0.9990 0.0000 71.56 0.00 0.00 0.00 0.00 0.00 0.00 1.05 0.00 0.00 71.56 1.05 0.0175 N C000206005 1.00 50164.07 50214.7400 0.9990 0.9990 0.9990 0.9990 0.0000 68.42 0.00 0.00 0.00 0.00 0.00 0.00 1.04 0.00 0.00 68.42 1.04 0.0168 N Federal Farm Credit Bank Federal Farm Credit Bank 313312BN9 US313312BN93 U.S. Government Agency Debt Y 2019-02-06 2019-02-06 2019-02-06 N N N 0.0242 4998340.00 4998340.00 0.0222 N N Y N Federal Farm Credit Bank Federal Farm Credit Bank 313312BU3 US313312BU37 U.S. Government Agency Debt Y 2019-02-12 2019-02-12 2019-02-12 N N N 0.0242 10092627.00 10092627.00 0.0448 N N Y N Federal Farm Credit Bank Federal Farm Credit Bank 313312CQ1 US313312CQ16 U.S. Government Agency Debt Y 2019-03-04 2019-03-04 2019-03-04 N N N 0.0244 2494832.50 2494832.50 0.0111 N N Y N Federal Farm Credit Bank Federal Farm Credit Bank 313312CU2 US313312CU28 U.S. Government Agency Debt Y 2019-03-08 2019-03-08 2019-03-08 N N N 0.0244 10176203.40 10176203.40 0.0452 N N Y N Federal Farm Credit Bank Federal Farm Credit Bank 313312CX6 US313312CX66 U.S. Government Agency Debt Y 2019-03-11 2019-03-11 2019-03-11 N N N 0.0244 7082015.70 7082015.70 0.0315 N N Y N Federal Farm Credit Bank Federal Farm Credit Bank 313312DE7 US313312DE76 U.S. Government Agency Debt Y 2019-03-18 2019-03-18 2019-03-18 N N N 0.0244 4985000.00 4985000.00 0.0221 N N Y N Federal Farm Credit Bank Federal Farm Credit Bank 313312DG2 US313312DG25 U.S. Government Agency Debt Y 2019-03-20 2019-03-20 2019-03-20 N N N 0.0244 5981202.00 5981202.00 0.0266 N N Y N Federal Home Loan Bank Federal Home Loan Bank 313384BQ1 2549001DPIFGXC1TOL40 US313384BQ10 U.S. Government Agency Debt Y 2019-02-08 2019-02-08 2019-02-08 N N N 0.0242 8196187.00 8196187.00 0.0364 N N Y N Federal Home Loan Bank Federal Home Loan Bank 313384BV0 2549001DPIFGXC1TOL40 US313384BV05 U.S. Government Agency Debt Y 2019-02-13 2019-02-13 2019-02-13 N N N 0.0243 9592348.80 9592348.80 0.0426 N N Y N Federal Home Loan Bank Federal Home Loan Bank 313384BX6 2549001DPIFGXC1TOL40 US313384BX60 U.S. Government Agency Debt Y 2019-02-15 2019-02-15 2019-02-15 N N N 0.0243 9391267.40 9391267.40 0.0417 N N Y N Federal Home Loan Bank Federal Home Loan Bank 313384CK3 2549001DPIFGXC1TOL40 US313384CK31 U.S. Government Agency Debt Y 2019-02-27 2019-02-27 2019-02-27 N N N 0.0243 8684983.80 8684983.80 0.0386 N N Y N Federal Home Loan Bank Federal Home Loan Bank 313384CL1 2549001DPIFGXC1TOL40 US313384CL14 U.S. Government Agency Debt Y 2019-02-28 2019-02-28 2019-02-28 N N N 0.0243 10830545.95 10830545.95 0.0481 N N Y N Federal Home Loan Mortgage Corp. Federal Home Loan Mortgage Corp. 313396CC5 S6XOOCT0IEG5ABCC6L87 US313396CC52 U.S. Government Agency Debt Y 2019-02-20 2019-02-20 2019-02-20 N N N 0.0243 5992434.00 5992434.00 0.0266 N N Y N Federal Home Loan Mortgage Corp. Federal Home Loan Mortgage Corp. 313396CR2 S6XOOCT0IEG5ABCC6L87 US313396CR22 U.S. Government Agency Debt Y 2019-03-05 2019-03-05 2019-03-05 N N N 0.0244 7084855.70 7084855.70 0.0315 N N Y N Federal Home Loan Mortgage Corp. Federal Home Loan Mortgage Corp. 313396DW0 S6XOOCT0IEG5ABCC6L87 US313396DW08 U.S. Government Agency Debt Y 2019-04-03 2019-04-03 2019-04-03 N N N 0.0244 9162583.60 9162583.60 0.0407 N N N N Federal Home Loan Mortgage Corp. Federal Home Loan Mortgage Corp. 313396DX8 S6XOOCT0IEG5ABCC6L87 US313396DX80 U.S. Government Agency Debt Y 2019-04-04 2019-04-04 2019-04-04 N N N 0.0244 9161976.40 9161976.40 0.0407 N N N N Federal Home Loan Mortgage Corp. Federal Home Loan Mortgage Corp. 313396EL3 S6XOOCT0IEG5ABCC6L87 US313396EL34 U.S. Government Agency Debt Y 2019-04-17 2019-04-17 2019-04-17 N N N 0.0245 10591775.00 10591775.00 0.0470 N N N N Federal Home Loan Mortgage Corp. Federal Home Loan Mortgage Corp. 313396ET6 S6XOOCT0IEG5ABCC6L87 US313396ET69 U.S. Government Agency Debt Y 2019-04-24 2019-04-24 2019-04-24 N N N 0.0245 3480865.50 3480865.50 0.0155 N N N N Federal National Mortgage Assoc. Federal National Mortgage Assoc. 313588BL8 B1V7KEBTPIMZEU4LTD58 US313588BL84 U.S. Government Agency Debt Y 2019-02-04 2019-02-04 2019-02-04 N N N 0.0242 1499701.50 1499701.50 0.0067 N N Y N Federal National Mortgage Assoc. Federal National Mortgage Assoc. 313588BN4 B1V7KEBTPIMZEU4LTD58 US313588BN41 U.S. Government Agency Debt Y 2019-02-06 2019-02-06 2019-02-06 N N N 0.0242 2499170.00 2499170.00 0.0111 N N Y N Federal National Mortgage Assoc. Federal National Mortgage Assoc. 313588BT1 B1V7KEBTPIMZEU4LTD58 US313588BT11 U.S. Government Agency Debt Y 2019-02-11 2019-02-11 2019-02-11 N N N 0.0242 2498340.00 2498340.00 0.0111 N N Y N Federal National Mortgage Assoc. Federal National Mortgage Assoc. 313588CB9 B1V7KEBTPIMZEU4LTD58 US313588CB93 U.S. Government Agency Debt Y 2019-02-19 2019-02-19 2019-02-19 N N N 0.0243 3898335.92 3898335.92 0.0173 N N Y N Federal National Mortgage Assoc. Federal National Mortgage Assoc. 313588CH6 B1V7KEBTPIMZEU4LTD58 US313588CH63 U.S. Government Agency Debt Y 2019-02-25 2019-02-25 2019-02-25 N N N 0.0243 9584707.20 9584707.20 0.0426 N N Y N Federal National Mortgage Assoc. Federal National Mortgage Assoc. 313588CJ2 B1V7KEBTPIMZEU4LTD58 US313588CJ20 U.S. Government Agency Debt Y 2019-02-26 2019-02-26 2019-02-26 N N N 0.0243 9184728.00 9184728.00 0.0408 N N Y N Federal National Mortgage Assoc. Federal National Mortgage Assoc. 313588CS2 B1V7KEBTPIMZEU4LTD58 US313588CS29 U.S. Government Agency Debt Y 2019-03-06 2019-03-06 2019-03-06 N N N 0.0244 5587680.00 5587680.00 0.0248 N N Y N Federal National Mortgage Assoc. Federal National Mortgage Assoc. 313588CY9 B1V7KEBTPIMZEU4LTD58 US313588CY96 U.S. Government Agency Debt Y 2019-03-12 2019-03-12 2019-03-12 N N N 0.0244 5784920.00 5784920.00 0.0257 N N Y N Federal National Mortgage Assoc. Federal National Mortgage Assoc. 313588CZ6 B1V7KEBTPIMZEU4LTD58 US313588CZ61 U.S. Government Agency Debt Y 2019-03-13 2019-03-13 2019-03-13 N N N 0.0244 4986665.00 4986665.00 0.0221 N N Y N Goldman Sachs & Co. LLC Goldman Sachs & Co. LLC 2.530000% FOR8UP27PHTHYVLBNG30 0000769993 318991007_2.53_0201 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 254900HROIFWPRGM1V77 2036-05-15 3.022258 0.10 0.06 U.S. Treasuries (including strips) FHLB 2019-04-22 2.351000 2563000.00 2549082.91 Agency Debentures and Agency Strips U.S. Treasury Bill 254900HROIFWPRGM1V77 2031-08-15 2.677052 10.23 7.13 U.S. Treasuries (including strips) U.S. Treasury Bill 254900HROIFWPRGM1V77 2041-08-15 3.023788 1800.00 909.20 U.S. Treasuries (including strips) U.S. Treasury Bill 254900HROIFWPRGM1V77 2037-02-15 3.023788 1.20 0.70 U.S. Treasuries (including strips) Y 2019-02-01 2019-02-01 2019-02-01 N N N 0.0253 2500000.00 2500000.00 0.0111 N Y Y N JPMorgan Chase JPMorgan Chase 2.550000% 8I5DZWZKVSZI1NUHU748 0001168163 446199002_2.55_0201 U.S. Treasury Repurchase Agreement, if collateralized only by U.S. Treasuries (including Strips) and cash Y N U.S. Treasury Bill 254900HROIFWPRGM1V77 2046-08-15 2.250000 15826400.00 13748676.66 U.S. Treasuries (including strips) U.S. Treasury Bill 254900HROIFWPRGM1V77 2027-01-15 2.375000 400.00 561.41 U.S. Treasuries (including strips) U.S. Treasury Bill 254900HROIFWPRGM1V77 2020-08-15 8.750000 300.00 339.91 U.S. Treasuries (including strips) Y 2019-02-01 2019-02-01 2019-02-01 N N N 0.0255 13479000.00 13479000.00 0.0599 N Y Y N U.S. Treasury Bill U.S. Treasury Bill 912796QW2 254900HROIFWPRGM1V77 US912796QW24 U.S. Treasury Debt Y 2019-02-07 2019-02-07 2019-02-07 N N N 0.0230 1999243.34 1999243.34 0.0089 N Y Y N U.S. Treasury Bill U.S. Treasury Bill 912796QY8 254900HROIFWPRGM1V77 US912796QY89 U.S. Treasury Debt Y 2019-02-21 2019-02-21 2019-02-21 N N N 0.0238 5692582.08 5692582.08 0.0253 N Y Y N U.S. Treasury Bill U.S. Treasury Bill 912796QZ5 254900HROIFWPRGM1V77 US912796QZ54 U.S. Treasury Debt Y 2019-03-07 2019-03-07 2019-03-07 N N N 0.0239 2195117.23 2195117.23 0.0097 N Y Y N U.S. Treasury Bill U.S. Treasury Bill 912796UM9 254900HROIFWPRGM1V77 US912796UM95 U.S. Treasury Debt Y 2019-02-05 2019-02-05 2019-02-05 N N N 0.0228 9636587.55 9636587.55 0.0428 N Y Y N U.S. Treasury Bill U.S. Treasury Bill 912796UN7 254900HROIFWPRGM1V77 US912796UN78 U.S. Treasury Debt Y 2019-02-12 2019-02-12 2019-02-12 N N N 0.0235 899364.06 899364.06 0.0040 N Y Y N U.S. Treasury Bill U.S. Treasury Bill 912796UR8 254900HROIFWPRGM1V77 US912796UR82 U.S. Treasury Debt Y 2019-03-05 2019-03-05 2019-03-05 N N N 0.0242 5588143.46 5588143.46 0.0248 N Y Y N MFS Series Trust I 2019-02-06 /s/Kino Clark Kino Clark Assistant Treasurer