N-MFP3 0001107414 XXXXXXXX 2026-05-31 STATE STREET INSTITUTIONAL INVESTMENT TRUST 0001107414 549300P1E098W6ES7M39 State Street Federal Treasury Plus Money Market Fund 984500FCIE7E84F01E90 S000086382 1 N N 333-30810 SSGA Funds Management, Inc. 801-60103 Ernst & Young LLP Boston MA SSGA Funds Management, Inc. SS&C GIDS, Inc. 0000027048 084-00448 Y 0001094885 Treasury Plus Money Market Portfolio S000019934 N N Government N N 1 1 76520796776.95 76620796776.95 0.9818 0.9831 2026-05-01 85233519081.72 85558519081.72 0.9812 0.9850 2026-05-04 86325564791.72 86650564791.72 0.9814 0.9851 2026-05-05 85201077499.43 85526077499.43 0.9812 0.9849 2026-05-06 72955915411.32 73760915411.32 0.9755 0.9863 2026-05-07 70183573450.39 70183573450.39 0.9815 0.9815 2026-05-08 71299733624.69 71299733624.69 0.9788 0.9788 2026-05-11 74015248114.77 74015248114.77 0.9796 0.9796 2026-05-12 71761379084.78 71761379084.78 0.9790 0.9790 2026-05-13 70591911977.69 70591911977.69 0.9786 0.9786 2026-05-14 70424992496.50 70424992496.50 0.9784 0.9784 2026-05-15 72334842526.88 72334842526.88 0.9790 0.9790 2026-05-18 72465368351.47 72465368351.47 0.9791 0.9791 2026-05-19 72269887039.35 72269887039.35 0.9790 0.9790 2026-05-20 71265356192.85 71265356192.85 0.9787 0.9787 2026-05-21 70028798614.57 70028798614.57 0.9780 0.9780 2026-05-22 70668486174.03 70668486174.03 0.9784 0.9784 2026-05-26 73762757121.93 73762757121.93 0.9792 0.9792 2026-05-27 73301847911.75 73301847911.75 0.9790 0.9790 2026-05-28 76773156744.97 76773156744.97 0.9798 0.9798 2026-05-29 0.00 102361900.40 102361900.40 0.00 458384.67 101903515.73 101903542.1550 Y 1.0000 0.0370 2026-05-01 0.0370 2026-05-04 0.0370 2026-05-05 0.0369 2026-05-06 0.0369 2026-05-07 0.0368 2026-05-08 0.0368 2026-05-11 0.0368 2026-05-12 0.0368 2026-05-13 0.0368 2026-05-14 0.0367 2026-05-15 0.0367 2026-05-18 0.0366 2026-05-19 0.0365 2026-05-20 0.0365 2026-05-21 0.0365 2026-05-22 0.0366 2026-05-26 0.0366 2026-05-27 0.0367 2026-05-28 0.0369 2026-05-29 1.0000 2026-05-01 1.0000 2026-05-04 1.0000 2026-05-05 1.0000 2026-05-06 1.0000 2026-05-07 1.0000 2026-05-08 1.0000 2026-05-11 1.0000 2026-05-12 1.0000 2026-05-13 1.0000 2026-05-14 1.0000 2026-05-15 1.0000 2026-05-18 1.0000 2026-05-19 1.0000 2026-05-20 1.0000 2026-05-21 0.9999 2026-05-22 1.0000 2026-05-26 0.9999 2026-05-27 0.9999 2026-05-28 1.0000 2026-05-29 N N Advantage Class C000251885 1000000.00 101903515.73 101903542.1550 1.0000 2026-05-01 1.0000 2026-05-04 1.0000 2026-05-05 1.0000 2026-05-06 1.0000 2026-05-07 1.0000 2026-05-08 1.0000 2026-05-11 1.0000 2026-05-12 1.0000 2026-05-13 1.0000 2026-05-14 1.0000 2026-05-15 1.0000 2026-05-18 1.0000 2026-05-19 1.0000 2026-05-20 1.0000 2026-05-21 0.9999 2026-05-22 1.0000 2026-05-26 0.9999 2026-05-27 0.9999 2026-05-28 1.0000 2026-05-29 2434302.93 68790.58 2026-05-01 762808.27 553890.40 2026-05-04 457201.02 206715.33 2026-05-05 639094.55 167274.57 2026-05-06 927810.44 568800.00 2026-05-07 230451.44 487484.85 2026-05-08 1297699.18 40436.24 2026-05-11 346663.89 108492.21 2026-05-12 60000.01 1452121.32 2026-05-13 851383.25 456379.20 2026-05-14 140405.19 208615.04 2026-05-15 540000.01 433764.65 2026-05-18 615497.47 709555.07 2026-05-19 1095828.30 896191.08 2026-05-20 148811.18 173090.41 2026-05-21 1207500.33 348709.05 2026-05-22 28933.45 256246.66 2026-05-26 415000.00 555543.18 2026-05-27 1217990.00 198025.00 2026-05-28 400100.00 1300655.32 2026-05-29 13817480.91 9190780.16 0.0331 2026-05-01 0.0331 2026-05-04 0.0331 2026-05-05 0.0330 2026-05-06 0.0330 2026-05-07 0.0329 2026-05-08 0.0329 2026-05-11 0.0329 2026-05-12 0.0329 2026-05-13 0.0329 2026-05-14 0.0328 2026-05-15 0.0328 2026-05-18 0.0327 2026-05-19 0.0326 2026-05-20 0.0326 2026-05-21 0.0326 2026-05-22 0.0327 2026-05-26 0.0327 2026-05-27 0.0328 2026-05-28 0.0330 2026-05-29 Y 6573.00 Broker-dealer 0.999 0.00 N State Street Treasury Plus Money Market Portfolio State Street Treasury Plus Money Market Portfolio FSSgAK1AW 5493008OWE0VKOXO4934 FSSgAK1AW Investment Company Y 2026-06-01 2026-06-01 2026-06-01 N N N 0.0000 102361900.40 102361900.40 1.0000 N Y Y N STATE STREET INSTITUTIONAL INVESTMENT TRUST 2026-06-05 /s/ Chad Hallett Chad Hallett Deputy Treasurer