<SEC-DOCUMENT>0001085146-16-004468-index.html : 20161011
<SEC-HEADER>0001085146-16-004468.hdr.sgml : 20161011
<ACCEPTANCE-DATETIME>20161011141243
ACCESSION NUMBER:		0001085146-16-004468
CONFORMED SUBMISSION TYPE:	SC 13G
PUBLIC DOCUMENT COUNT:		1
FILED AS OF DATE:		20161011
DATE AS OF CHANGE:		20161011

SUBJECT COMPANY:	

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			GULFPORT ENERGY CORP
		CENTRAL INDEX KEY:			0000874499
		STANDARD INDUSTRIAL CLASSIFICATION:	CRUDE PETROLEUM & NATURAL GAS [1311]
		IRS NUMBER:				731521290
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		SC 13G
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	005-51297
		FILM NUMBER:		161930789

	BUSINESS ADDRESS:	
		STREET 1:		14313 NORTH MAY AVENUE
		STREET 2:		SUITE 100
		CITY:			OKLAHOMA CITY
		STATE:			OK
		ZIP:			73134
		BUSINESS PHONE:		4058488807

	MAIL ADDRESS:	
		STREET 1:		14313 NORTH MAY AVENUE
		STREET 2:		SUITE 100
		CITY:			OKLAHOMA CITY
		STATE:			OK
		ZIP:			73134

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	WRT ENERGY CORP
		DATE OF NAME CHANGE:	19930328

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	WESTERN RESOURCE TECHNOLOGIES INC
		DATE OF NAME CHANGE:	19600201

FILED BY:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			Boston Partners
		CENTRAL INDEX KEY:			0001386060
		IRS NUMBER:				980202744
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		SC 13G

	BUSINESS ADDRESS:	
		STREET 1:		ONE BEACON STREET
		CITY:			BOSTON
		STATE:			MA
		ZIP:			02108
		BUSINESS PHONE:		2129089500

	MAIL ADDRESS:	
		STREET 1:		909 THIRD AVENUE
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10022

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	Robeco Investment Management, Inc.
		DATE OF NAME CHANGE:	20070111
</SEC-HEADER>
<DOCUMENT>
<TYPE>SC 13G
<SEQUENCE>1
<FILENAME>gpor_100716.htm
<DESCRIPTION>ROBECO INVESTMENT MANAGEMENT INC.
<TEXT>
Document 1 - file: gpor_100716.htm

</DOCUMENT>
</SEC-DOCUMENT>