X0306 4 2021-04-09 0 0001333835 Casa Systems Inc CASA 0001802372 Bruckner Scott C/O CASA SYSTEMS, INC. 100 OLD RIVER ROAD ANDOVER MA 01810 0 1 0 0 CFO Common Stock 2021-04-09 4 M 0 14098 A 99866 D Common Stock 2021-04-09 4 F 0 6259 9.87 D 93607 D Restricted Stock Units 2021-04-09 4 M 0 14098 0.00 D Common Stock 14098 0 D Restricted stock units ("RSUs") converted into common stock, $0.001 par value per share (the "Common Stock"), of Casa Systems, Inc. (the "Company") on a one-for-one basis upon vesting of the units. Shares withheld by the Company to satisfy tax withholding requirements on vesting of RSUs. No shares were sold. Each RSU represents the right to receive one share of Common Stock upon vesting, subject to the reporting person's continued service relationship with the Company and the other terms and conditions set forth in the applicable RSU agreement. In the sole discretion of the Company's board of directors, the Company may, with respect to any applicable vesting date, deliver to the reporting person Common Stock or cash having a fair market value equal to the number of shares of Common Stock underlying the portion of the RSU that vested on such date, payable within 30 days of the vesting date, less applicable taxes. The RSUs are scheduled to vest based upon the Company's level of achievement of pre-established performance parameters, as approved by the Company's Board of Directors, related to either or both of (i) the Company's relative Total Shareholder Return ("TSR") performance against the TSR of the companies listed in the Russell 2000 Index, and (ii) the absolute stock price performance of the Company's common stock, in each case, measured over the three-year period beginning on February 25, 2020 and ending on February 25, 2023, and subject to the other terms and conditions set forth in the applicable RSU agreement. The RSUs have no expiration date. /s/ Timothy Rodenberger, as Attorney-in-Fact 2021-04-13