13G HTML File DOCUMENT TYPE SC 13G
TEXT


SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549
SCHEDULE 13G
Under the Securities Exchange Act of 1934


Name of Issuer: MARINUS PHARMACEUTICALS, INC.
_____________________________________________________
Title of Class
of Securities: Common Stock

CUSIP Number: 56854Q101

1) NAME AND I.R.S. IDENTIFICATION NO. OF REPORTING PERSON

Prudential Financial, Inc. 22-3703799

2.) MEMBER OF A GROUP: (a) N/A
(b) N/A

3) SEC USE ONLY:



4) PLACE OF ORGANIZATION: New Jersey

NUMBER OF SHARES BENEFICIALLY OWNED BY REPORTING PERSON WITH:

5) Sole Voting Power: 0 See Exhibit A
6) Shared Voting Power: 2,696,553 See Exhibit A
7) Sole Dispositive Power: 0 See Exhibit A
8) Shared Dispositive Power: 2,696,553 See Exhibit A

9) AGGREGATE AMOUNT BENEFICIALLY OWNED: 2,696,553 See Exhibit A

10) AGGREGATE AMOUNT IN ROW (9) EXCLUDES SHARES: Not Applicable

11) PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9): 6.7 See Exhibit A

12) TYPE OF REPORTING PERSON: HC

ITEM 1(a). NAME OF ISSUER:

MARINUS PHARMACEUTICALS, INC.

ITEM 1(b). ADDRESS OF ISSUER'S EXECUTIVE OFFICES:

170 N RADNOR CHESTER RD
SUITE 250
RADNOR, PA 19087


ITEM 2(a). NAME OF PERSON FILING:

Prudential Financial, Inc.

ITEM 2(b). ADDRESS OF PRINCIPAL BUSINESS OFFICE:

751 Broad Street
Newark, New Jersey 07102-3777

ITEM 2(c). CITIZENSHIP:

New Jersey

ITEM 2(d). TITLE OF CLASS OF SECURITIES:

Common Stock

ITEM 2(e). CUSIP NUMBER:

56854Q101

ITEM 3. The Person filing this statement is a Parent Holding Company as
defined in Section 240.13d-1(b)(1)(ii)(G) of the Securities Exchange
Act of 1934.

ITEM 4. OWNERSHIP:

(a) Number of Shares
Beneficially Owned: 2,696,553
See Exhibit A

(b) Percent of Class: 6.7


(c) Powers                No. Of Shares
----------- --------------------
Sole power to vote or 0 See Exhibit A to direct the vote
Shared power to vote or 2,696,553 See Exhibit A to direct the vote
Sole power to dispose or 0 See Exhibit A to direct disposition
Shared power to dispose 2,696,553 See Exhibit A or to direct disposition

ITEM 5. OWNERSHIP OF 5% OR LESS OF A CLASS:

Not Applicable

ITEM 6. OWNERSHIP OF MORE THAN 5% ON BEHALF OF
ANOTHER PERSON:
Our clients may have the right to receive or the power to direct the receipt of
dividends from, or the proceeds from the sale of, such securities which are the
subject of this filing.

ITEM 7. IDENTIFICATION AND CLASSIFICATION OF THE
SUBSIDIARY WHICH ACQUIRED THE SECURITY BEING
REPORTED ON BY THE ULTIMATE PARENT COMPANY:

See Exhibit A

ITEM 8. IDENTIFICATION AND CLASSIFICATION OF
MEMBERS OF THE GROUP:

Not Applicable

ITEM 9. NOTICE OF DISSOLUTION OF GROUP:

Not Applicable

ITEM 10. CERTIFICATION:

By signing below, Prudential Financial, Inc. certifies that, to the best of its
knowledge and belief, the securities referred to above were acquired
and are held in the ordinary course of business and were not acquired
and are not held for the purpose of or with the effect of changing or
influencing the control of the issuer of the securities and were not acquired
and are not held in connection with or as a participant in any transaction
having that purpose or effect.


The filing of this statement should not be construed as an admission that
Prudential Financial, Inc. is, for purposes of Sections 13 or 16 of the Securities
Exchange Act of 1934, the beneficial owner of such shares.


SIGNATURE

After reasonable inquiry and to the best of its knowledge and belief,
Prudential Financial, Inc. certifies that the information set forth in this
statement is true, complete and correct.

PRUDENTIAL FINANCIAL, INC.

By: Richard Baker
Second Vice President

Date: 01/19/2018
As of: 12/31/2017

Exhibit A
--------------

ITEM 4. OWNERSHIP:

Through its parent/subsidiary relationship, Prudential Financial, Inc. may be
deemed the beneficial owner of the same securities as the Item 7 listed
subsidiaries and may have direct or indirect voting and/or investment
discretion over 2,696,553 shares.

These shares were acquired in the ordinary course of business, and not with the
purpose or effect of changing or influencing control of the Issuer.  The filing
of this statement should not be construed as an admission that Prudential
Financial, Inc. is, for the purposes of Sections 13 or 16 of the Securities
Exchange Act of 1934, the beneficial owner of these shares.


ITEM 7. IDENTIFICATION/CLASSIFICATION:

Prudential Financial, Inc. is a Parent Holding Company and the indirect parent
of the following subsidiaries, who are the beneficial owners of the number and
percentage of securities which are the subject of this filing as set forth next
to their names:



Subsidiaries Number of Shares Percentage
The Prudential Insurance Company of America IC 0 0
Prudential Retirement Insurance and Annuity Company IC 0 0
Jennison Associates LLC IA 2,696,553 6.67
PGIM, Inc. IA 0 0
Quantitative Management Associates LLC IA 0 0