X0306 4 2021-11-18 0 0001796022 StepStone Group Inc. STEP 0001585937 ARG Private Equity, LLC 6733 S. YALE AVE. TULSA OK 74136 0 0 1 0 0001394221 ARGO Holdings, LLC 6733 S. YALE AVE. TULSA OK 74136 0 0 1 0 0001163432 KAISER GEORGE B C/O FREDERIC DORWART, LAWYERS PLLC 124 EAST FOURTH STREET TULSA OK 74103 0 0 1 0 0001610279 Mitchell Steven R C/O ASPEN AEROGELS, INC. 30 FORBES ROAD, BUILDING B NORTHBOROUGH MA 01532 1 0 1 0 0001728668 Waldo Robert 6733 S. YALE AVE. TULSA, OK 74136 0 0 1 0 Class B Common Stock 2021-11-18 4 D 0 1330336 0.001 D 3662708 D Class A Common Stock 2021-11-18 4 C 0 1330336 A 1382836 D Class A Common Stock 2021-11-18 4 S 0 1330336 51.83 D 52500 D Class B Units 2021-11-18 4 C 0 1330336 D Class A Common Stock 1330336 3662708 D On November 18, 2021, the Reporting Person exchanged 1,330,336 Class B Units of StepStone Group LP for 1,330,336 shares of Class A Common Stock. In connection with the exchange, 1,330,336 shares of Class B Common Stock were automatically redeemed and cancelled. 27,500 of the Class A Common Stock securities are held of record by Steven R. Mitchell. Each of ARG Private Equity, LLC, ARGO Holdings, LLC, George Kaiser and Robert A. Waldo disclaims beneficial ownership of these securities to the extent it or he does not have a pecuniary interest therein. 25,000 of the Class A Common Stock securities are held of record by Robert A. Waldo. Each of ARG Private Equity, LLC, ARGO Holdings, LLC, George Kaiser and Steven R. Mitchell disclaims beneficial ownership of these securities to the extent it or he does not have a pecuniary interest therein. The remaining securities are held of record by ARGO Holdings, LLC. ARGO Holdings, LLC is managed by ARG Private Equity, LLC Steven R. Mitchell has a derivative interest in ARG Private Equity, LLC. Robert A. Waldo is a manager and Vice President of ARG Private Equity, LLC and has a derivative interest therein. George B. Kaiser is the sole member of ARG Private Equity, LLC. Each of Steven R. Mitchell, Robert A. Waldo and George B. Kaiser disclaims beneficial ownership of the securities reported herein for purposes of Rule 16a-1(a) under the Securities and Exchange Act of 1934, as amended, except to the extent of his pecuniary interest therein, if any. The Class B Units are exchangeable, on a one-for-one basis, for shares of Class A Common Stock of the Issuer. Upon exchange of a Class B Unit, the corresponding share of Class B Common Stock of the Issuer will be automatically redeemed and cancelled. On November 18, 2021, the Reporting Person sold shares of Class A Common Stock in a secondary offering of Class A Common Stock by certain selling stockholders of the Issuer. ARG Private Equity, LLC; By /s/ Frederic Dorwart, Manager 2021-11-19 ARGO Holdings, LLC; By ARG Private Equity, LLC, Manager; By /s/ Frederic Dorwart, Manager 2021-11-19 /s/ Frederic Dorwart, Attorney-in-fact for George B. Kaiser 2021-11-19 /s/ Steven R. Mitchell 2021-11-19 /s/ Robert A. Waldo 2021-11-19