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* Plunkett Debora A (Last) (First) (Middle) 50 MINUTEMAN ROAD (Street) ANDOVER MA 01810 (City) (State) (Zip)	2. Date of Event Requiring Statement (Month/Day/Year) 10/27/2021	3. Issuer Name and Ticker or Trading Symbol MERCURY SYSTEMS INC [ MRCY ]
		4. Relationship of Reporting Person(s) to Issuer (Check all applicable) X Director 10% Owner Officer (give title below) Other (specify below)	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)
	Date Exercisable	Expiration Date	Title	Amount or Number of Shares

Explanation of Responses:

Remarks:

No securities are beneficially owned.

	/s/ Michelle McCarthy, Attorney-in-Fact for Debora Plunkett	10/29/2021
	** 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.

LIMITED POWER OF ATTORNEY
FOR
MERCURY SYSTEMS, INC.
SECTION 16(a) FILINGS
Know all by these presents, that the undersigned hereby constitutes
and appoints each of
Michael D. Ruppert, the Chief Financial Officer, Christopher C.
Cambria, the General Counsel,
and Michelle M. McCarthy, the Chief Accounting Officer, of Mercury
Systems, Inc., acting
singly, the undersigned's true and lawful attorney-in-fact to:
(1) prepare, execute in the undersigned's name and on the
undersigned's behalf, and
submit to the U.S. Securities and Exchange Commission (the "SEC") a
Form ID,
including amendments thereto, and any other documents necessary or
appropriate
to obtain codes and passwords enabling the undersigned to make
electronic filings
with the SEC of reports required by Section 16(a) of the Securities
Exchange Act
of 1934, as amended (the "Exchange Act"), or any rule or regulation
of the SEC;
(2) execute for and on behalf of the undersigned, in the
undersigned's capacity as an
officer, director, and/or shareholder of Mercury Systems, Inc. (the
"Company"),
Forms 3, 4, 5, and 144 and amendments thereto, in accordance with
Section 16(a)
of the Exchange Act and the rules thereunder;
(3) do and perform any and all acts for and on behalf of the
undersigned which may
be necessary or desirable to complete and execute any such Form 3, 4,
5 or 144,
or amendments thereto, and timely file such form with the SEC and any
stock
exchange or similar authority; and
(4) take any other action of any type whatsoever which, in the
opinion of such
attorney-in-fact, may be necessary or desirable in connection with
the foregoing
authority, it being understood that the documents executed by each
such attorneyin-
fact on behalf of the undersigned pursuant to this Limited Power of
Attorney
shall be in such form and shall contain such terms and conditions as
such
attorney-in-fact may approve, provided, however, that the undersigned
does not
grant to each such power-of-attorney the right to engage in any
transactions
involving the securities of the Company on behalf of the undersigned,
including
without limitation, the right to purchase or sell any securities of
the Company.
The undersigned hereby grants to each such attorney-in-fact full
power and authority to
do and perform any and every act and thing whatsoever requisite,
necessary, or proper to be done
in the exercise of any of the rights and powers herein granted, as
fully to all intents and purposes
as the undersigned might or could do if personally present, with full
power of substitution or
revocation, hereby ratifying and confirming all that each such
attorney-in-fact, or each such
attorney-in-fact's substitute or substitutes (any such substitute
also being referred to herein as an
"attorney-in-fact"), shall lawfully do or cause to be done by virtue
of this Limited Power of
Attorney and the rights and powers herein granted. The undersigned
acknowledges that each
attorney-in-fact, in serving in such capacity at the request of the
undersigned or such attorney-infact,
is not assuming, nor is the Company assuming, any of the
undersigned's responsibilities to
comply with Section 16 of the Exchange Act.
The undersigned agrees that each such attorney-in-fact shall not be
liable for any error of
judgment or for any act done or omitted to be done or for any mistake
of fact or law except for
each such attorney-in-fact's own bad faith, and the undersigned
agrees to indemnify and to hold
each such attorney-in-fact han-nless against any loss, claim, damage,
liability, or cost incurred on
each such attorney-in-fact's part arising out of or in connection
with acts undertaken or omitted
to be taken as an attorney-in-fact hereunder.
This Limited Power of Attorney shall remain in full force and effect
until the undersigned
is no longer required to file Forms 3, 4, 5, and 144 with respect to
the undersigned's holdings of
and transactions in securities of Mercury Systems, Inc., unless
earlier revoked by the
undersigned in a signed writing delivered to the foregoing attorneys-
in-fact. This Limited Power
of Attorney may be filed with the SEC as a confirming statement of
the authority granted herein.
IN WITNESS WHEREOF, the undersigned has caused this Limited Power of
Attorney to
be executed as of this 27th day of October, 2021.
By: /s/ Debora A Plunkett
Name: Debora A. Plunkett
Title: Member of the Board of Directors
Affix Notary Stamp
The Commonwealth of Massachusetts
On this 27 day of October 2021 before me the
undersigned notary public, Debora A. Plunkett
personally appeared before me, and proved to me through
satisfactory evidence all identification, which were
personally known, to be the person whose name is
signed on the preceding or attached document in my presence.
/s/ Ann M. Cronin
Ann M. Cronin, Notary Public
.../ My Commission Expires November 25, 2027