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Exhibit 4.1    
    

[SPECIMEN UNIT CERTIFICATE]

	NUMBER	 	 	 	UNITS
	U-	 	 	 	 

PROSPECT ACQUISITION CORP.
  Incorporated Under the Laws of the State of Delaware

	 	 	CUSIP	 	 

SEE
REVERSE FOR

CERTAIN DEFINITIONS 

UNITS CONSISTING OF ONE SHARE OF COMMON STOCK AND

ONE WARRANT EACH TO PURCHASE ONE SHARE OF COMMON STOCK

This certifies that                        is the owner
of                        Units. 

Each
Unit ("Unit") consists of one (1) share of common stock, par value $0.0001 per share ("Common Stock"), of Prospect Acquisition Corp., a Delaware corporation (the "Company"), and one
warrant (each a "Warrant"). Each Warrant entitles the holder to purchase one (1) share of Common Stock for $7.50 per share (subject to adjustment). Each Warrant will become exercisable on the
later of (i) the Company's completion of a merger, capital stock exchange, asset acquisition or other similar business combination and (ii)
                         , 2009, and will expire unless
exercised before 5:00 p.m., New York time, on                        , 2012, or earlier upon redemption. The Common Stock and
Warrants comprising the Units represented by this certificate are not
transferable separately prior to                        , 2007 unless Citigroup Global Markets, Inc. elects to allow separate
trading earlier, subject to the Company's (i) filing of a Current
Report on Form 8-K with the Securities and Exchange Commission containing an audited balance sheet reflecting the Company's receipt of the gross proceeds of the Company's initial
public offering and (ii) issuance of a press release announcing when such separate trading will begin. The terms of the Warrants are governed by a Warrant Agreement, dated as of
                        , 2007, by and between the Company and Continental Stock Transfer & Trust Company, as Warrant
Agent, and are subject to the terms and provisions contained therein, all of which
terms and provisions the holder of this certificate consents to by acceptance hereof. Copies of the Warrant Agreement are on file at the office of the Warrant Agent at 17 Battery Place, New York, New
York 10004, and are available to any Warrant holder on written request and without cost. 

This
certificate is not valid unless countersigned by the Transfer Agent and Registrar of the Company. 

Witness
the facsimile seal of the Company and the facsimile signatures of its duly authorized officers. 

	Dated:	 	 
	, 2007	 	[Corporate Seal]

Delaware	 	 
 Authorized Officer

 
Prospect Acquisition Corp.

        The
Company will furnish without charge to each stockholder who so requests, a statement of the powers, designations, preferences and relative, participating, optional or other special
rights of each class of stock or series thereof of the Company and the qualifications, limitations, or restrictions of such preferences and/or rights. This certificate and the Units represented hereby
are issued and shall be held subject to the terms and conditions applicable to the securities underlying and comprising the Units. 

        The
following abbreviations, when used in the inscription on the face of this certificate, shall be construed as though they were written out in full according to applicable laws or
regulations: 

	 	TEN COM	 	as tenant in common	 	UNIF GIFT MIN ACT	 	 
 (Cust)	 	Custodian	 	 
 (Minor)
	

 	

TEN ENT	
 	

tenants by the entireties	
 	

Under Uniform Gifts to Minors Act:

 
 (State)	
 	

 	
 	

 
	

 	

JT TEN	
 	

as joint tenants with right of

survivorship and not as tenants

in common	
 	

 	
 	

 	
 	

 	
 	

 

Additional
abbreviations may also be used though not in the above list. 

For value received,                        hereby sells, assigns and transfers
unto                        

	PLEASE INSERT SOCIAL SECURITY OR OTHER

IDENTIFYING NUMBER OF ASSIGNEE	 	 
	

 
	
 	

 
	

 
 (PLEASE PRINT OR TYPEWRITE NAME AND ADDRESS, INCLUDING ZIP CODE, OF ASSIGNEE)

                        Units represented by the within Certificate, and do hereby irrevocably constitute and
appoint                        Attorney to transfer said Units on the books of
the within named Company with full power of substitution in the premises.

	Dated	 	 
	 	 
Notice: The signature to this assignment must correspond with the name as written upon the face of the certificate in every particular, without alteration or enlargement or any
change whatever.
	

Signatures(s) Guaranteed:	
 	

 
	

 
	
 	

 
	THE SIGNATURE(S) SHOULD BE GUARANTEED BY AN ELIGIBLE GUARANTOR INSTITUTION (BANKS, STOCKBROKERS, SAVINGS AND LOAN ASSOCIATIONS AND CREDIT UNIONS WITH MEMBERSHIP IN AN APPROVED SIGNATURE GUARANTEE MEDALLION
PROGRAM, PURSUANT TO S.E.C. RULE 17Ad-15).

2

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Exhibit 4.2    
    

[Specimen Common Stock Certificate]

	NUMBER	 	 	 	SHARES
	 
	 	 	 	 

PROSPECT ACQUISITION CORP.
  Incorporated Under the Laws of the State of Delaware

	 	 	 	 	COMMON STOCK	 	CUSIP	 	 

SEE
REVERSE FOR

CERTAIN DEFINITIONS 

This Certifies that                        is the registered holder
of                         

FULLY PAID AND NON-ASSESSABLE SHARES OF THE PAR VALUE OF $0.0001

EACH OF THE COMMON STOCK OF  

 PROSPECT ACQUISITION CORP.

transferable on the books of the Prospect Acquisition Corp. (the "Company") in person or by duly authorized attorney upon
surrender of this certificate properly endorsed.

The Company will be forced to liquidate if it is unable to complete a business combination
by                        , 2009, all as more fully described in the Company's final
prospectus dated                        , 2007.

This Certificate is not valid unless countersigned by the Transfer Agent and registered by the Registrar. Witness the seal of the Company and the facsimile signatures of its
duly authorized officers.

	Dated:	 	 
	 	 	 	 
	

 	
 	

 	
 	

Corporate Seal	
 	

 
	

 	
 	

 	
 	

Delaware	
 	

 
	

 
 CHIEF EXECUTIVE OFFICER	
 	

 	
 	

 
 SECRETARY

 
Prospect Acquisition Corp.

        The
Company will furnish without charge to each stockholder who so requests the powers, designations, preferences and relative participating, optional or other special rights of each
class of stock or series thereof of the Company and the qualifications, limitations, or restrictions of such preferences and/or rights. This certificate and the shares represented hereby are issued
and shall be held subject to all the provisions of the Certificate of Incorporation and all amendments thereto and resolutions of the Board of Directors providing for the issue of shares of Preferred
Stock (copies of which may be obtained from the secretary of the Company), to all of which the holder of this certificate by acceptance hereof assents. 

        The
following abbreviations, when used in the inscription on the face of this certificate, shall be construed as though they were written out in full according to applicable laws or
regulations: 

	 	TEN COM	 	as tenant in common	 	UNIF GIFT MIN ACT	 	 
 (Cust)	 	Custodian	 	 
 (Minor)
	

 	

TEN ENT	
 	

tenants by the entireties	
 	

Under Uniform Gifts to Minors Act:

 
 (State)	
 	

 	
 	

 
	

 	

JT TEN	
 	

as joint tenants with right of

survivorship and not as

tenants in common	
 	

 	
 	

 	
 	

 	
 	

 

        Additional
abbreviations may also be used though not in the above list. 

        For value received,                        hereby sell, assign and transfer
unto                        

	PLEASE INSERT SOCIAL SECURITY OR OTHER

IDENTIFYING NUMBER OF ASSIGNEE	 	 
	

 
	
 	

 
	

 
 (PLEASE PRINT OR TYPEWRITE NAME AND ADDRESS, INCLUDING ZIP CODE, OF ASSIGNEE)

                        shares of the capital stock represented by the within Certificate, and do hereby
irrevocably constitute and appoint                        Attorney to transfer said
stock on the books of the within named Company with full power of substitution in the premises.

	Dated	 	 
	 	 
Notice: The signature to this assignment must correspond with the name as written upon the face of the certificate in every particular, without alteration or enlargement or any
change whatever.
	

Signatures(s) Guaranteed:	
 	

 
	

 
	
 	

 
	THE SIGNATURE(S) SHOULD BE GUARANTEED BY AN ELIGIBLE GUARANTOR INSTITUTION (BANKS, STOCKBROKERS, SAVINGS AND LOAN ASSOCIATIONS AND CREDIT UNIONS WITH MEMBERSHIP IN AN APPROVED SIGNATURE GUARANTEE MEDALLION
PROGRAM, PURSUANT TO S.E.C. RULE 17Ad-15).

The holder of this certificate shall be entitled to receive funds from the Company's trust account only in the event of a liquidation of the Company upon failure to consummate
a business combination or if the holder seeks to convert his, her or its respective shares into cash upon a business combination which he, she or it voted against and which is actually completed by
the Company. In no other circumstances shall the holder have any right or interest of any kind in or to the trust account.

2

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Exhibit 4.3    
    

[Form of Warrant Certificate]

[Face]

	NUMBER	 	 	 	WARRANTS
	 
	 	 	 	 

THIS WARRANT WILL BE VOID IF NOT EXERCISED PRIOR TO

5:00 P.M. NEW YORK CITY TIME,                        , 2012

PROSPECT ACQUISITION CORP.
  Incorporated Under the Laws of the State of Delaware

	 	 	CUSIP	 	 

WARRANT CERTIFICATE

        This Warrant Certificate certifies that                        , or registered assigns,
is the registered holder of                        warrants (the  "Warrants") to purchase shares of Common Stock, $.0001 par value (the "Common Stock"), of Prospect
Acquisition Corp., a Delaware corporation (the "Company"). Each Warrant entitles the holder, upon exercise during the period set forth in the Warrant
Agreement referred to below, to purchase from the Company that number of fully paid and non-assessable shares of Common Stock (each, a "Warrant
Share") as set forth below at the exercise price (the "Exercise Price") as determined pursuant to the Warrant Agreement payable
in lawful money of the United States of America upon surrender of this Warrant Certificate and payment of the Exercise Price at the office or agency of the Warrant Agent, but only subject to the
conditions set forth herein and in the Warrant Agreement. Defined terms used in this Warrant Certificate but not defined herein shall have the meanings given to them in the Warrant Agreement. 

        Each
Warrant is initially exercisable for one fully paid and non-assessable share of Common Stock. The number of Warrant Shares issuable upon exercise of the Warrants is
subject to adjustment upon the occurrence of certain events set forth in the Warrant Agreement. 

        The
initial Exercise Price per share of Common Stock for any Warrant is equal to $7.50 per share. The Exercise Price is subject to adjustment upon the occurrence of certain events set
forth in the Warrant Agreement. 

        Warrants
may be exercised only during the Warrant Exercise Period subject to the conditions set forth in the Warrant Agreement and to the extent not exercised by the end of such Warrant
Exercise Period such Warrants shall become void. 

        Reference
is hereby made to the further provisions of this Warrant Certificate set forth on the reverse hereof and such further provisions shall for all purposes have the same effect as
though fully set forth at this place. 

        This
Warrant Certificate shall not be valid unless countersigned by the Warrant Agent, as such term is used in the Warrant Agreement. 

        This
Warrant Certificate shall be governed and construed in accordance with the internal laws of the State of New York, without regard to conflicts of laws principles thereof. 

	 	 	 	 	PROSPECT ACQUISITION CORP.
	

 	
 	

 	
 	

By:	
 	

 
 David A. Minella

Chief Executive Officer
	

Countersigned:

Dated:                        , 20 

CONTINENTAL STOCK TRANSFER & TRUST COMPANY,

as Warrant Agent	
 	

 	
 	

 
	

By:	
 	

 
 Authorized Signatory	
 	

 	
 	

 

 
[Form of Warrant Certificate]

[Reverse]

        The
Warrants evidenced by this Warrant Certificate are part of a duly authorized issue of Warrants entitling the holder on exercise to receive shares of Common Stock, par value $0.0001
per share, of the Company (the "Common Stock"), and are issued or to be issued pursuant to a Warrant Agreement dated as of
[                        ], 2007 (the "Warrant Agreement"), duly executed
and delivered by the Company to Continental Stock
Transfer & Trust Company, a New York corporation, as warrant agent (the "Warrant Agent"), which Warrant Agreement is hereby incorporated by
reference in and made a part of this instrument and is hereby referred to for a description of the rights, limitation of rights, obligations, duties and immunities thereunder of the Warrant Agent, the
Company and the holders (the words "holders" or "holder" meaning the registered holders or registered holder) of the Warrants. A copy of the Warrant Agreement may be obtained by the holder hereof upon
written request to the Company. Defined terms used in this Warrant Certificate but not defined herein shall have the meanings given to them in the Warrant Agreement. 

        Warrants
may be exercised at any time during the Warrant Exercise Period set forth in the Warrant Agreement. The holder of Warrants evidenced by this Warrant Certificate may exercise
them by surrendering this Warrant Certificate, with the form of election to purchase set forth hereon properly completed and executed, together with payment of the Exercise Price as specified in the
Warrant Agreement, at the principal corporate trust office of the Warrant Agent. In the event that upon any exercise of Warrants evidenced hereby the number of Warrants exercised shall be less than
the total number of Warrants evidenced hereby, there shall be issued to the holder hereof or his assignee a new Warrant Certificate evidencing the number of Warrants not exercised. No adjustment shall
be made for any dividends on any Common Stock issuable upon exercise of this Warrant. 

        Notwithstanding
anything else in this Warrant Certificate or the Warrant Agreement, no Warrant may be exercised unless at the time of exercise (i) a registration statement
covering the Warrant Shares to be issued upon exercise is effective under the Act and (ii) a prospectus thereunder relating to the Warrant Shares is current. In no event shall the Warrants be
settled on a net cash basis during the Warrant Exercise Period nor shall the Company be required to issue unregistered shares upon the exercise of any Warrant. 

        Once
the Warrants become exercisable and there is an effective registration statement covering the shares of Common Stock issuable upon exercise of the Warrants available and current
throughout the 30-day redemption period defined below, the Company may redeem the outstanding Warrants (except with respect to the sponsors' Warrants held by a sponsor or its permitted
transferee) in whole and not in part at a price of $0.01 per Warrant upon a minimum of 30 days' prior written notice of redemption (the "30-day redemption
period'') and if, and only if, the last sale price of the Company's Common Stock equals or exceeds $14.50 per share for any 20 trading days within a 30-trading day
period ending three business days before the notice of redemption is sent. If the Company calls the Warrants for redemption, it will have the option to require all holders that wish to exercise
Warrants to do so on a "cashless basis." In such event, each holder would pay the exercise price by surrendering the Warrants for that number of shares of Common Stock equal to the quotient obtained
by dividing (x) the product of the number of shares of Common Stock underlying the Warrants, multiplied by the difference between the exercise price of the Warrants and the "fair market value"
(defined below) by (y) the fair market value. The "fair market value" shall mean the average reported last sale price of the Common Stock for the
ten trading days ending on the third trading day prior to the date on which the notice of redemption is sent to the holders of Warrants. 

        The
Warrant Agreement provides that upon the occurrence of certain events the number of Warrant Shares set forth on the face hereof may, subject to certain conditions, be adjusted. No
fractions of a share of Common Stock will be issued upon the exercise of any Warrant, but the Company will pay the cash value thereof determined as provided in the Warrant Agreement. 

        Warrant
Certificates, when surrendered at the principal corporate trust office of the Warrant Agent by the registered holder thereof in person or by legal representative or attorney duly
authorized in writing, may be exchanged, in the manner and subject to the limitations provided in the Warrant Agreement, but without payment of any service charge, for another Warrant Certificate or
Warrant Certificates of like tenor evidencing in the aggregate a like number of Warrants. 

        Upon
due presentation for registration of transfer of this Warrant Certificate at the office of the Warrant Agent a new Warrant Certificate or Warrant Certificates of like tenor and
evidencing in the aggregate a like number of Warrants shall be issued to the transferee(s) in exchange for this Warrant Certificate, subject to the limitations provided in the Warrant Agreement,
without charge except for any tax or other governmental charge imposed in connection therewith. 

        The
Company and the Warrant Agent may deem and treat the registered holder(s) thereof as the absolute owner(s) of this Warrant Certificate (notwithstanding any notation of ownership or
other writing hereon made by anyone), for the purpose of any exercise hereof, of any distribution to the holder(s) hereof, and for all other purposes, and neither the Company nor the Warrant Agent
shall be affected by any notice to the contrary. Neither the Warrants nor this Warrant Certificate entitles any holder hereof to any rights of a stockholder of the Company. 

2

 
Election
to Purchase 

(To
Be Executed Upon Exercise Of Warrant) 

The
undersigned hereby irrevocably elects to exercise the right, represented by this Warrant Certificate, to
receive                        shares of Common Stock and herewith tenders payment for such shares
to the order of Prospect Acquisition Corp. in the amount of $                        in accordance with the terms hereof. The
undersigned requests that a certificate for such shares be registered in the name
of                        , whose address
is                        and that such shares be delivered
to                        whose address
is                        . If said number of shares is less than all of the shares of
Common Stock purchasable hereunder, the undersigned requests that a new Warrant Certificate representing the remaining balance of such shares be registered in the name
of                        , whose
address is                        , and that such Warrant Certificate be delivered
to                        , whose address
is                        . 

In
the event that the Warrant has been called for redemption by the Company pursuant to Section 6(b) of the Warrant Agreement and the Company has required cashless exercise pursuant to
Section 6(d) of the Warrant Agreement, the number of shares that a Warrant is exercisable for shall be determined in accordance with Section 6(d) of the Warrant Agreement. 

In
the event that the Warrant is a Sponsors' Warrant (as such term is defined in the Warrant Agreement), such Warrant may be exercised, to the extent allowed by the Warrant Agreement, through cashless
exercise pursuant to Section 6(d) of the Warrant Agreement, in which case, (i) the number of shares that a Sponsors' Warrant is exercisable for would be determined in accordance with
Section 6(d) of the Warrant Agreement and (ii) the holder of the Sponsors' Warrant will complete the following: 

        The
undersigned hereby irrevocably elects to exercise the right, represented by its Sponsors' Warrant Certificate, through the cashless exercise provision of Section 6(d) of the
Warrant Agreement, to receive                        shares of Common Stock. If said number of shares is less than all of the
shares of Common Stock purchasable hereunder (after giving effect to the cashless
exercise), the undersigned requires that a new Sponsors' Warrant Certificate representing the balance of such shares be registered in the name
of                        , whose address
is                        , and
that such Sponsors' Warrant Certificate be delivered to                        , whose address
is                        . 

	Dated:	 	 
	 	 
	

 	
 	

 	
 	

 
 (SIGNATURE)
	

 	
 	

 	
 	

 
 
 
 (ADDRESS)
	

 	
 	

 	
 	

 
 (TAX IDENTIFICATION NUMBER)
	

Signatures(s) Guaranteed:	
 	

 
	

 
	
 	

 
	THE SIGNATURE(S) SHOULD BE GUARANTEED BY AN ELIGIBLE GUARANTOR INSTITUTION (BANKS, STOCKBROKERS, SAVINGS AND LOAN ASSOCIATIONS AND CREDIT UNIONS WITH MEMBERSHIP IN AN APPROVED SIGNATURE GUARANTEE MEDALLION
PROGRAM, PURSUANT TO S.E.C. RULE 17Ad-15).

3

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Exhibit 4.3

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