N-MFP2 0001060517 XXXXXXXX 2021-02-28 0001060517 S000067420 1 N N 333-52965 UBS ASSET MANAGEMENT (AMERICAS), INC. 801-34910 Ernst & Young LLP New York NY UBS ASSET MANAGEMENT (AMERICAS) INC. BNY Mellon Investment Servicing (US) Inc. 0000849542 084-01761 Y 0001403166 ESG Prime Master Fund S000068192 N N Prime N 1 1 160827962.11 164242023.02 158952084.65 161569379.63 166127927.91 181241686.90 194351877.98 201568988.64 0.00 0.3800 0.3837 0.3458 0.3312 0.3925 0.4234 0.4228 0.4132 0.0000 0.00 199712260.87 0.00 0.00 32075.16 199680185.71 199571252.3580 0.0000 0.0014 1.0005 1.0005 1.0005 1.0005 0.0000 C000216777 1000000.00 199680185.71 199571252.3580 1.0005 1.0005 1.0005 1.0005 0.0000 2461770.99 10328341.80 1405374.23 1391811.13 18131967.00 5499268.44 37023712.99 51074713.42 0.00 0.00 59022825.21 68294134.79 0.0006 N ESG Prime Master Fund ESG Prime Master Fund 0001403166 935LYUII3 Investment Company Y 2021-03-01 2021-03-01 2021-03-01 N N N 0.0000 199712260.87 199712260.87 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 2021-03-05 /s/Rose Ann Bubloski Rose Ann Bubloski Vice President