MFS Institutional Money Market Portfolio Fund Information and Unaudited Holdings as of March 31, 2020 Weighted Average Maturity: 19 days Weighted Average Life: 19 days Final Maturity Date Maturity Date Coupon Rate Issuer Category of Investment CUSIP Principal Amount (a) (b) (c) Value 3M Co. Non-Financial Company Commercial Paper 88580CD60 50,000,000 04/06/20 04/06/20 1.70000% 49,993,083.50 American Honda Finance Corp. Non-Financial Company Commercial Paper 02665JD80 100,842,000 04/08/20 04/08/20 1.80000% 100,826,201.08 American Honda Finance Corp. Non-Financial Company Commercial Paper 02665JEM8 25,000,000 05/21/20 05/21/20 1.67300% 24,955,729.25 Apple, Inc. Non-Financial Company Commercial Paper 03785DD78 65,000,000 04/07/20 04/07/20 1.58000% 64,988,877.85 Apple, Inc. Non-Financial Company Commercial Paper 03785DDM5 100,000,000 04/21/20 04/21/20 1.15100% 99,925,333.00 Apple, Inc. Non-Financial Company Commercial Paper 03785DDP8 50,000,000 04/23/20 04/23/20 1.15100% 49,959,111.00 Apple, Inc. Non-Financial Company Commercial Paper 03785DDU7 29,000,000 04/28/20 04/28/20 1.05100% 28,971,128.76 Bank of Montreal Certificate of Deposit 06367BFA2 147,000,000 04/06/20 04/06/20 1.70000% 147,034,023.15 Bank of Montreal Certificate of Deposit 06367BKF5 106,000,000 04/02/20 04/02/20 0.10000% 105,999,587.66 U.S. Treasury Repurchase Agreement, if BOFA Securities Repurchase Agreement collateralized only by U.S. Treasuries 4F9949D 250,000,000 04/01/20 04/01/20 0.01000% 250,000,000.00 (including Strips) and cash Canadian Imperial Bank of Commerce Financial Company Commercial Paper 13608AEK8 90,000,000 05/19/20 05/19/20 1.61200% 89,864,637.30 Chevron Corp. Non-Financial Company Commercial Paper 16677JET9 24,000,000 05/27/20 05/27/20 1.25200% 23,952,439.92 Chevron Corp. Non-Financial Company Commercial Paper 16677JDM5 54,755,000 04/21/20 04/21/20 1.95200% 54,694,951.83 Chevron Corp. Non-Financial Company Commercial Paper 16677JD60 50,000,000 04/06/20 04/06/20 1.05000% 49,990,716.50 Chevron Corp. Non-Financial Company Commercial Paper 16677JDE3 100,000,000 04/14/20 04/14/20 1.45100% 99,926,733.00 Coca-Cola Co. Non-Financial Company Commercial Paper 19121AD65 60,000,000 04/06/20 04/06/20 1.15000% 59,995,170.00 Coca-Cola Co. Non-Financial Company Commercial Paper 19121ADN8 11,500,000 04/22/20 04/22/20 1.95100% 11,491,074.74 Exxon Mobil Corp. Non-Financial Company Commercial Paper 30229ADT3 105,900,000 04/27/20 04/27/20 2.04300% 105,756,002.48 Exxon Mobil Corp. Non-Financial Company Commercial Paper 30229ADM8 40,000,000 04/21/20 04/21/20 0.92100% 39,960,800.00 Exxon Mobil Corp. Non-Financial Company Commercial Paper 30229ADP1 50,400,000 04/23/20 04/23/20 2.00200% 50,344,487.42 Exxon Mobil Corp. Non-Financial Company Commercial Paper 30229ADQ9 15,880,000 04/24/20 04/24/20 2.00200% 15,861,505.04 Exxon Mobil Corp. Non-Financial Company Commercial Paper 30229ADG1 50,000,000 04/16/20 04/16/20 2.00100% 49,964,511.00 Federal Home Loan Banks U.S. Government Agency Debt 313384XD6 10,517,000 05/22/20 05/22/20 0.00000% 10,515,957.03 Federal Home Loan Banks U.S. Government Agency Debt 313384WV7 96,200,000 05/14/20 05/14/20 0.00000% 96,191,956.72 Federal Home Loan Banks U.S. Government Agency Debt 313384WM7 27,715,000 05/06/20 05/06/20 1.57000% 27,713,113.72 Federal Home Loan Banks U.S. Government Agency Debt 313384VX4 50,000,000 04/22/20 04/22/20 1.28000% 49,997,958.50 Federal Home Loan Banks U.S. Government Agency Debt 313384YQ6 88,500,000 06/26/20 06/26/20 0.01900% 88,485,201.03 Federal Home Loan Banks U.S. Government Agency Debt 313384VH9 562,435,000 04/08/20 04/08/20 1.16900% 562,427,345.26 Federal Home Loan Banks U.S. Government Agency Debt 313384VB2 25,300,000 04/02/20 04/02/20 1.00000% 25,299,950.92 Federal Home Loan Banks U.S. Government Agency Debt 313384VC0 207,718,000 04/03/20 04/03/20 1.52500% 207,717,191.98 Federal Home Loan Banks U.S. Government Agency Debt 313384VF3 100,000,000 04/06/20 04/06/20 1.56000% 99,999,028.00 Federal Home Loan Banks U.S. Government Agency Debt 313384VG1 150,000,000 04/07/20 04/07/20 1.57000% 149,998,249.50 Federal Home Loan Banks U.S. Government Agency Debt 313384YV5 31,000,000 07/01/20 07/01/20 0.03000% 30,992,947.50 Federal Home Loan Banks U.S. Government Agency Debt 313384VN6 274,900,000 04/13/20 04/13/20 0.76700% 274,893,586.58 Federal Home Loan Banks U.S. Government Agency Debt 313384VQ9 69,450,000 04/15/20 04/15/20 1.57000% 69,448,109.57 Federal Home Loan Mortgage Corp. U.S. Government Agency Debt 313396VH3 192,200,000 04/08/20 04/08/20 0.00000% 192,197,384.16 U.S. Government Agency Repurchase Agreement, collateralized only by U.S. Goldman Sachs Repurchase Agreement 4F9978D 41,100,000 04/01/20 04/01/20 0.00000% 41,100,000.00 Government Agency securities, U.S. Treasuries, and cash U.S. Treasury Repurchase Agreement, if J.P. Morgan Repurchase Agreement collateralized only by U.S. Treasuries 4F9992D 123,165,000 04/01/20 04/01/20 0.01000% 123,165,000.00 (including Strips) and cash J.P. Morgan Securities, LLC Financial Company Commercial Paper 46640PD91 13,000,000 04/09/20 04/09/20 1.50000% 12,997,097.75 J.P. Morgan Securities, LLC Financial Company Commercial Paper 46640PD83 90,760,000 04/08/20 04/08/20 1.75000% 90,743,037.86 J.P. Morgan Securities, LLC Financial Company Commercial Paper 46640PDV2 7,000,000 04/29/20 04/29/20 1.25100% 6,992,669.46 J.P. Morgan Securities, LLC Financial Company Commercial Paper 46640PDH3 152,705,000 04/17/20 04/17/20 1.50100% 152,616,087.51 Merck & Co., Inc. Non-Financial Company Commercial Paper 58934ADE3 50,000,000 04/14/20 04/14/20 1.30100% 49,970,075.00 Merck & Co., Inc. Non-Financial Company Commercial Paper 58934ADL7 100,000,000 04/20/20 04/20/20 1.33100% 99,897,389.00 Merck & Co., Inc. Non-Financial Company Commercial Paper 58934ADM5 25,000,000 04/21/20 04/21/20 1.33100% 24,972,583.25 Merck & Co., Inc. Non-Financial Company Commercial Paper 58934AE51 64,230,000 05/05/20 05/05/20 1.30200% 64,113,663.41 Merck & Co., Inc. Non-Financial Company Commercial Paper 58934ADQ6 17,300,000 04/24/20 04/24/20 1.85200% 17,278,317.39 Page 1 of 2 Mizuho Bank Ltd. Financial Company Commercial Paper 60689FE53 50,000,000 05/05/20 05/05/20 1.65700% 49,949,687.50 Mizuho Bank Ltd. Financial Company Commercial Paper 60689FFH6 29,500,000 06/17/20 06/17/20 1.61900% 29,423,939.27 National Bank of Canada Financial Company Commercial Paper 63307LDD0 25,000,000 04/13/20 04/13/20 1.75100% 24,990,069.50 National Bank of Canada Financial Company Commercial Paper 63307LE49 114,000,000 05/04/20 05/04/20 1.65200% 113,860,033.08 Nestle Capital Corp. Non-Financial Company Commercial Paper 64105GDP6 74,842,000 04/23/20 04/23/20 1.59100% 74,783,665.15 Nestle Capital Corp. Non-Financial Company Commercial Paper 64105GDQ4 50,000,000 04/24/20 04/24/20 1.59100% 49,959,333.50 Nestle Capital Corp. Non-Financial Company Commercial Paper 64105GDT8 50,000,000 04/27/20 04/27/20 1.59100% 49,954,250.00 Novartis Finance Corp. Non-Financial Company Commercial Paper 6698M4D66 34,000,000 04/06/20 04/06/20 0.48200% 33,995,925.78 Novartis Finance Corp. Non-Financial Company Commercial Paper 6698M4E57 50,000,000 05/05/20 05/05/20 1.15100% 49,938,604.00 Novartis Finance Corp. Non-Financial Company Commercial Paper 6698M4DV1 20,000,000 04/29/20 04/29/20 1.55200% 19,979,377.80 Novartis Finance Corp. Non-Financial Company Commercial Paper 6698M4D17 33,943,000 04/01/20 04/01/20 0.00000% 33,942,610.67 Novartis Finance Corp. Non-Financial Company Commercial Paper 6698M4DU3 50,000,000 04/28/20 04/28/20 1.15100% 49,950,222.00 PepsiCo, Inc. Non-Financial Company Commercial Paper 71344TDQ2 22,100,000 04/24/20 04/24/20 1.56100% 22,080,994.00 Siemens Capital Co. LLC Non-Financial Company Commercial Paper 82619TDQ7 100,000,000 04/24/20 04/24/20 0.85100% 99,912,000.00 Siemens Capital Co. LLC Non-Financial Company Commercial Paper 82619TD12 5,916,000 04/01/20 04/01/20 0.00000% 5,915,789.63 Siemens Capital Co. LLC Non-Financial Company Commercial Paper 82619TD38 95,590,000 04/03/20 04/03/20 0.40000% 95,579,803.41 Siemens Capital Co.