SEC FORM 3

SEC Form 3

FORM 3

UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

INITIAL STATEMENT OF BENEFICIAL OWNERSHIP OF SECURITIES

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934
or Section 30(h) of the Investment Company Act of 1940

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1. Name and Address of Reporting Person^*

McCarthy Shaun N.

(Last)

(First)

(Middle)

C/O CASA SYSTEMS, INC.

100 OLD RIVER ROAD

(Street)

ANDOVER

01810

(City)

(State)

(Zip)

2. Date of Event Requiring Statement (Month/Day/Year)
08/15/2018

3. Issuer Name and Ticker or Trading Symbol
Casa Systems Inc [ CASA ]

4. Relationship of Reporting Person(s) to Issuer
(Check all applicable)

	Director	10% Owner
X	Officer (give title below)	Other (specify below)
	Interim CFO

5. If Amendment, Date of Original Filed (Month/Day/Year)

6. Individual or Joint/Group Filing (Check Applicable Line)

X	Form filed by One Reporting Person
	Form filed by More than One Reporting Person

Table I - Non-Derivative Securities Beneficially Owned
1. Title of Security (Instr. 4)	2. Amount of Securities Beneficially Owned (Instr. 4)	3. Ownership Form: Direct (D) or Indirect (I) (Instr. 5)	4. Nature of Indirect Beneficial Ownership (Instr. 5)

Table II - Derivative Securities Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 4)	2. Date Exercisable and Expiration Date (Month/Day/Year)		3. Title and Amount of Securities Underlying Derivative Security (Instr. 4)		4. Conversion or Exercise Price of Derivative Security	5. Ownership Form: Direct (D) or Indirect (I) (Instr. 5)	6. Nature of Indirect Beneficial Ownership (Instr. 5)
1. Title of Derivative Security (Instr. 4)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares	4. Conversion or Exercise Price of Derivative Security	5. Ownership Form: Direct (D) or Indirect (I) (Instr. 5)	6. Nature of Indirect Beneficial Ownership (Instr. 5)
Stock option (right to buy)	⁽¹⁾	06/10/2024	Common Stock	31,925	$2.29	D
Restricted Stock Units⁽²⁾	⁽³⁾	⁽³⁾	Common Stock	5,405	$0.00	D

Explanation of Responses:

1. The option is currently vested as to 30,360 shares, and the remaining 1,565 shares are scheduled to vest on August 31, 2018.

2. Each Restricted Stock Unit ("RSU") represents the right to receive one share of common stock, $0.001 par value per share (the "Common Stock") of Casa Systems, Inc. (the "Company") 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.

3. The RSUs are scheduled to vest as to 25% of the original number of RSUs on June 14, 2019, and as to an additional 25% upon completion of each year thereafter.

Remarks:

Exhibit 24.1 - Limited Power of Attorney for Section 16 Reporting Obligations

	/s/ Todd Keebaugh, attorney-in-fact	08/22/2018
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* If the form is filed by more than one reporting person, see Instruction 5 (b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.