Exhibit 99.3

Designated Filer: Warburg Pincus Private Equity IX, L.P.

Issuer & Ticker Symbol: Laredo Petroleum Holdings, Inc. [LPI]

Date of Event Requiring Statement: August 19, 2013

JOINT FILERS’ SIGNATURES

WARBURG PINCUS IX LLC
By: Warburg Pincus Partners LLC, its Sole Member
	By: Warburg Pincus & Co., its Managing Member
By:		/s/ Scott A. Arenare		Date:	August 19, 2013
		Name:	Scott A. Arenare
		Title:	Attorney-in-Fact*
WARBURG PINCUS PARTNERS LLC
By: Warburg Pincus & Co., its Managing Member
By:		/s/ Scott A. Arenare		Date:	August 19, 2013
		Name:	Scott A. Arenare
		Title:	Attorney-in-Fact*
WARBURG PINCUS LLC
By:		/s/ Scott A. Arenare		Date:	August 19, 2013
		Name:	Scott A. Arenare
		Title:	Managing Director
WARBURG PINCUS & CO.
By:		/s/ Scott A. Arenare		Date:	August 19, 2013
		Name:	Scott A. Arenare
		Title:	Attorney-in-Fact*
CHARLES R. KAYE
By:		/s/ Scott A. Arenare		Date:	August 19, 2013
		By: Scott A. Arenare, Attorney-in-Fact*
JOSEPH P. LANDY
By:		/s/ Scott A. Arenare		Date:	August 19, 2013
		By:  Scott A. Arenare, Attorney-in-Fact*

*The Power of Attorney given by each of Warburg Pincus & Co., Mr. Kaye and Mr. Landy was previously filed with the U.S. Securities & Exchange Commission on January 15, 2013 as an exhibit to a statement on Schedule 13D/A filed by Warburg Pincus Private Equity X, L.P. with respect to Talon Therapeutics, Inc. and is hereby incorporated by reference.