N-MFP3 0001060517 XXXXXXXX 2026-07-31 UBS Series Funds 0001060517 54930058UKPXVB81RJ71 UBS Select 100% US Treasury Preferred Fund 529900FTKZBAKZ4ON106 S000084283 2 N N 333-52965 UBS ASSET MANAGEMENT (AMERICAS) LLC 801-34910 Ernst & Young LLP New York NY UBS ASSET MANAGEMENT (AMERICAS) LLC BNY Mellon Investment Servicing (US) Inc. 0000849542 084-01761 Y 0001403166 100 [percent symbol] US Treasury Master Fund S000085171 N N Government N Y 1 1 18552492750.72 18552492750.72 0.9996 0.9996 2026-07-01 18616339566.28 18616339566.28 0.9996 0.9996 2026-07-02 19339139047.23 19339139047.23 0.9996 0.9996 2026-07-06 18994618467.83 18994618467.83 0.9995 0.9995 2026-07-07 19119811240.39 19119811240.39 0.9995 0.9995 2026-07-08 19036453247.36 19036453247.36 0.9995 0.9995 2026-07-09 19182255616.26 19182255616.26 0.9995 0.9995 2026-07-10 19375340013.99 19375340013.99 0.9995 0.9995 2026-07-13 19049724615.55 19049724615.55 0.9995 0.9995 2026-07-14 19112476786.92 19112476786.92 0.9995 0.9995 2026-07-15 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0.0371 2026-07-22 0.0372 2026-07-23 0.0372 2026-07-24 0.0372 2026-07-27 0.0373 2026-07-28 0.0373 2026-07-29 0.0373 2026-07-30 0.0374 2026-07-31 1.0000 2026-07-01 1.0000 2026-07-02 1.0000 2026-07-06 1.0000 2026-07-07 1.0000 2026-07-08 1.0000 2026-07-09 1.0000 2026-07-10 1.0000 2026-07-13 1.0000 2026-07-14 1.0000 2026-07-15 1.0000 2026-07-16 1.0000 2026-07-17 1.0000 2026-07-20 1.0000 2026-07-21 1.0000 2026-07-22 0.9999 2026-07-23 0.9999 2026-07-24 0.9999 2026-07-27 1.0000 2026-07-28 1.0001 2026-07-29 1.0001 2026-07-30 1.0001 2026-07-31 N N Class P C000248580 1.00 582000183.30 581986849.2000 1.0000 2026-07-01 1.0000 2026-07-02 1.0000 2026-07-06 1.0000 2026-07-07 1.0000 2026-07-08 1.0000 2026-07-09 1.0000 2026-07-10 1.0000 2026-07-13 1.0000 2026-07-14 1.0000 2026-07-15 1.0000 2026-07-16 1.0000 2026-07-17 1.0000 2026-07-20 1.0000 2026-07-21 1.0000 2026-07-22 0.9999 2026-07-23 0.9999 2026-07-24 0.9999 2026-07-27 1.0000 2026-07-28 1.0001 2026-07-29 1.0001 2026-07-30 1.0001 2026-07-31 12674463.36 7280770.26 2026-07-01 5802781.87 2405408.05 2026-07-02 18571291.52 6800696.87 2026-07-06 12418680.03 4772672.93 2026-07-07 8791050.21 9167161.99 2026-07-08 3778200.35 4102498.54 2026-07-09 7463994.97 5459270.79 2026-07-10 2021347.25 8185540.30 2026-07-13 12894859.17 4949594.35 2026-07-14 10354747.03 4971349.24 2026-07-15 10365973.88 7507158.86 2026-07-16 4719595.51 10107925.46 2026-07-17 7123740.02 16724925.25 2026-07-20 3878397.59 6916116.07 2026-07-21 6192208.36 15275960.16 2026-07-22 8041817.70 7906336.82 2026-07-23 4709504.26 6195590.69 2026-07-24 4018072.23 10276739.57 2026-07-27 5064372.18 8504500.71 2026-07-28 6197530.40 8305803.50 2026-07-29 13848752.95 5736470.89 2026-07-30 8773649.23 2127365.79 2026-07-31 177705030.07 163679857.09 0.0356 2026-07-01 0.0356 2026-07-02 0.0356 2026-07-06 0.0356 2026-07-07 0.0356 2026-07-08 0.0356 2026-07-09 0.0356 2026-07-10 0.0356 2026-07-13 0.0356 2026-07-14 0.0356 2026-07-15 0.0356 2026-07-16 0.0357 2026-07-17 0.0357 2026-07-20 0.0357 2026-07-21 0.0357 2026-07-22 0.0358 2026-07-23 0.0358 2026-07-24 0.0358 2026-07-27 0.0359 2026-07-28 0.0359 2026-07-29 0.0359 2026-07-30 0.0360 2026-07-31 Y 28550.00 Retail investor 0.0703 0.00 N Class T C000250059 5000000.00 10039258468.47 10039066008.5600 1.0000 2026-07-01 1.0000 2026-07-02 1.0000 2026-07-06 1.0000 2026-07-07 1.0000 2026-07-08 1.0000 2026-07-09 1.0000 2026-07-10 1.0000 2026-07-13 1.0000 2026-07-14 1.0000 2026-07-15 1.0000 2026-07-16 1.0000 2026-07-17 1.0000 2026-07-20 1.0000 2026-07-21 1.0000 2026-07-22 0.9999 2026-07-23 0.9999 2026-07-24 0.9999 2026-07-27 1.0000 2026-07-28 1.0001 2026-07-29 1.0001 2026-07-30 1.0001 2026-07-31 575299871.63 357358786.36 2026-07-01 86156464.28 43143350.15 2026-07-02 353093430.04 8196865.60 2026-07-06 18596130.01 15960301.36 2026-07-07 5861573.29 54003198.65 2026-07-08 180224285.21 159663301.23 2026-07-09 25106931.29 21082807.16 2026-07-10 1730241.54 23058202.56 2026-07-13 5998868.61 32908840.81 2026-07-14 152749799.93 253251763.34 2026-07-15 11449498.42 7659747.44 2026-07-16 30960266.97 12514005.53 2026-07-17 12249275.84 14370766.39 2026-07-20 20538520.63 14006292.60 2026-07-21 515390495.53 11759144.22 2026-07-22 7533961.39 19827748.17 2026-07-23 17934561.53 45974264.22 2026-07-24 26475181.29 76803787.79 2026-07-27 1096945.58 6233095.65 2026-07-28 35100050.66 14806374.98 2026-07-29 14723848.89 8463485.18 2026-07-30 14049757.20 37983639.38 2026-07-31 2112319959.76 1239029768.77 0.0356 2026-07-01 0.0356 2026-07-02 0.0356 2026-07-06 0.0356 2026-07-07 0.0356 2026-07-08 0.0356 2026-07-09 0.0356 2026-07-10 0.0356 2026-07-13 0.0356 2026-07-14 0.0356 2026-07-15 0.0356 2026-07-16 0.0357 2026-07-17 0.0357 2026-07-20 0.0357 2026-07-21 0.0357 2026-07-22 0.0358 2026-07-23 0.0358 2026-07-24 0.0358 2026-07-27 0.0359 2026-07-28 0.0359 2026-07-29 0.0359 2026-07-30 0.0360 2026-07-31 Y 468584.00 Retail investor 0.0645 0.00 Retail investor 0.0614 0.00 N 100 [percent symbol] US Treasury Master Fund 100 [percent symbol] US Treasury Master Fund 902656883 5299000M97HC3J8TJ387 0001403166 Investment Company Y 2026-08-03 2026-08-03 2026-08-03 N N N 0.0000 10655271052.95 10655271052.95 1.0000 N Y Y N The master-feeder funds are parties to a written daily liquidity agreement; consistent with SEC staff interpretative guidance, ownership interests in the master fund are categorized as a Daily Liquid Asset/Weekly Liquid Asset by the feeder funds. UBS Series Funds 2026-08-07 /s/Rose Ann Bubloski Rose Ann Bubloski Vice President