Schedule 13G/A
 
UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549
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SCHEDULE 13G
(Amendment No. 1)
 
Under the Securities Exchange Act of 1934

United Therapeutics Corporation
(Name of Issuer)
 
Common Stock, par value $.01 per share and associated preferred stock purchase rights
(Title of Class of Securities)
 
91307C102
(CUSIP Number)
 

December 31, 2006
(Date of Event which Requires Filing of this Statement)
 


Check the appropriate box to designate the rule pursuant to which this Schedule is filed:

¨ Rule 13d-1(b)
 
ý Rule 13d-1(c)
 
¨ Rule 13d-1(d)
 

 
* The remainder of this cover page shall be filled out for a reporting person's initial filing on this form with respect to the subject class of securities, and for any subsequent amendment containing information which would alter disclosures provided in a prior cover page.
 
The information required in the remainder of this cover page shall not be deemed to be “filed” for the purpose of Section 18 of the Securities Exchange Act of 1934 (“Act”) or otherwise subject to the liabilities of that section of the Act but shall be subject to all other provisions of the Act (however, see the Notes).

 

 

 



 


 
CUSIP No. 91307C102
 
13G
 
Page 2 of 10 Pages


1
 
NAMES OF REPORTING PERSONS
I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY)
Ziff Asset Management, L.P.
2
 
CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (SEE INSTRUCTIONS)
(a) ¨
(b) ¨
 
3
 
SEC USE ONLY
 
4
 
CITIZENSHIP OR PLACE OF ORGANIZATION
 
Delaware
 
NUMBER OF
 
SHARES
 
BENEFICIALLY
 
OWNED BY
EACH
 
REPORTING
PERSON
 
WITH
 
5
 
SOLE VOTING POWER
 
0
6
 
SHARED VOTING POWER
 
1,550,815
7
 
SOLE DISPOSITIVE POWER
 
0
8
 
SHARED DISPOSITIVE POWER
 
1,550,815
9
 
AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
 
1,550,815
10
 
CHECK IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES (SEE INSTRUCTIONS)
 
o
 
11
 
PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)
 
6.7%
12
 
TYPE OF REPORTING PERSON (SEE INSTRUCTIONS)
 
PN

 
 



 


 
CUSIP No. 91307C102
 
13G
 
Page 3 of 10 Pages


1
 
NAMES OF REPORTING PERSONS
I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY)
PBK Holdings, Inc.
2
 
CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (SEE INSTRUCTIONS)
(a) ¨
(b) ¨
 
3
 
SEC USE ONLY
 
4
 
CITIZENSHIP OR PLACE OF ORGANIZATION
 
Delaware
 
NUMBER OF
 
SHARES
 
BENEFICIALLY
 
OWNED BY
EACH
 
REPORTING
PERSON
 
WITH
 
5
 
SOLE VOTING POWER
 
0
6
 
SHARED VOTING POWER
 
1,550,815
7
 
SOLE DISPOSITIVE POWER
 
0
8
 
SHARED DISPOSITIVE POWER
 
1,550,815
9
 
AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
 
1,550,815
10
 
CHECK IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES (SEE INSTRUCTIONS)
 
o
 
11
 
PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)
 
6.7%
12
 
TYPE OF REPORTING PERSON (SEE INSTRUCTIONS)
 
CO

 
 



 

 
CUSIP No. 91307C102
 
13G
 
Page 4 of 10 Pages


1
 
NAMES OF REPORTING PERSONS
I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY)
Philip B. Korsant
2
 
CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (SEE INSTRUCTIONS)
(a) ¨
(b) ¨
 
3
 
SEC USE ONLY
 
4
 
CITIZENSHIP OR PLACE OF ORGANIZATION
 
United States of America
 
NUMBER OF
 
SHARES
 
BENEFICIALLY
 
OWNED BY
EACH
 
REPORTING
PERSON
 
WITH
 
5
 
SOLE VOTING POWER
 
0
6
 
SHARED VOTING POWER
 
1,550,815
7
 
SOLE DISPOSITIVE POWER
 
0
8
 
SHARED DISPOSITIVE POWER
 
1,550,815
9
 
AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
 
1,550,815
10
 
CHECK IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES (SEE INSTRUCTIONS)
 
o
 
11
 
PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)
 
6.7%
12
 
TYPE OF REPORTING PERSON (SEE INSTRUCTIONS)
 
IN
 



 


 
CUSIP No. 91307C102
 
13G
 
Page 5 of 10 Pages


1
 
NAMES OF REPORTING PERSONS
I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY)
ZBI Equities, L.L.C.
2
 
CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (SEE INSTRUCTIONS)
(a) ¨
(b) ¨
 
3
 
SEC USE ONLY
 
4
 
CITIZENSHIP OR PLACE OF ORGANIZATION
 
Delaware
 
NUMBER OF
 
SHARES
 
BENEFICIALLY
 
OWNED BY
EACH
 
REPORTING
PERSON
 
WITH
 
5
 
SOLE VOTING POWER
 
0
6
 
SHARED VOTING POWER
 
1,550,815
7
 
SOLE DISPOSITIVE POWER
 
0
8
 
SHARED DISPOSITIVE POWER
 
1,550,815
9
 
AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
 
1,550,815
10
 
CHECK IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES (SEE INSTRUCTIONS)
 
o
 
11
 
PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)
 
6.7%
12
 
TYPE OF REPORTING PERSON (SEE INSTRUCTIONS)
 
IA

 
 


Page 6 of 10 Pages
 

Item 1. (a)    Name of Issuer
 
United Therapeutics Corporation
 
Item 1. (b)    Address of Issuer’s Principal Executive Offices
 
1110 Spring Street
Silver Spring, MD 20910
 
Item 2. (a)    Name of Person Filing
 
This Schedule 13G is being filed on behalf of the following persons (the “Reporting Persons”)*:
 
(i)
Ziff Asset Management, L.P. (“ZAM”);
(ii)
PBK Holdings, Inc. (“PBK”);
(iii)
Philip B. Korsant; and
(iv)
 
ZBI Equities, L.L.C. (“ZBI”).
 
* Attached as Exhibit A is a copy of an agreement among the Reporting Persons that this Schedule 13G is being filed on behalf of each of them.
 
Item 2. (b)    Address of Principal Business Office or, if None, Residence
 
Ziff Asset Management, L.P.
283 Greenwich Avenue
Greenwich, CT 06830
 
PBK Holdings, Inc.
283 Greenwich Avenue
Greenwich, CT 06830
 
Philip B. Korsant
283 Greenwich Avenue
Greenwich, CT 06830
 
ZBI Equities, L.L.C.
283 Greenwich Avenue
Greenwich, CT 06830
 
Item 2. (c)    Citizenship
 
See Item 4 of the attached cover pages.
 
Item 2. (d)    Title of Class of Securities
 
Common Stock, par value $.01 per share and associated preferred stock purchase rights (the “Common Stock”)
 
Item 2. (e)    CUSIP Number
 
91307C102
 
 


Page 7 of 10 Pages
 

Item 3.
 
Not applicable as this Schedule 13G is filed pursuant to Rule 13d-1(c).
 
Item 4.                Ownership
 
(a)
 
Amount beneficially owned:
 
 
See Item 9 of the attached cover pages.
 
(b)
 
Percent of class:
 
 
See Item 11 of the attached cover pages.
 
(c)
 
Number of shares as to which such person has:
 
 
(i)
 
Sole power to vote or to direct the vote:
 
 
 
 
See Item 5 of the attached cover pages.
 
  (ii)
Shared power to vote or to direct the vote:
 
   
See Item 6 of the attached cover pages.
 
 
(iii)
 
Sole power to dispose or to direct the disposition:
 
   
See Item 7 of the attached cover pages.
 
 
(iv)
 
Shared power to dispose or to direct the disposition:
 
   
See Item 8 of the attached cover pages.
 
Item 5.                Ownership of Five Percent or Less of a Class
 
Not Applicable.
 
Item 6.                Ownership of More than Five Percent on Behalf of Another Person
 
ZAM is the owner of record of the shares of Common Stock reported herein. Each of PBK, Philip B. Korsant, and ZBI may be deemed to beneficially own the Common Stock reported herein as a result of the direct or indirect power to vote or dispose of such stock.
 
Item 7.         Identification and Classification of the Subsidiary Which Acquired the Security Being Reported on by the Parent Holding Company
 
Not Applicable.
 
 
 


Page 8 of 10 Pages
 

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 I certify that, to the best of my knowledge and belief, the securities referred to above 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.
 
 
 


Page 9 of 10 Pages
 


SIGNATURE


After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

Dated: February 12, 2007

 
ZIFF ASSET MANAGEMENT, L.P.
By: PBK Holdings, Inc., its general partner
 
 
By:
/s/ DAVID GRAY
 
Name:
David Gray
 
Title:
 
Vice President
 
 
PBK HOLDINGS, INC.
 
 
 
By:
/s/ DAVID GRAY
 
Name:
David Gray
 
Title:
 
Vice President
 
   
   
/s/ PHILIP B. KORSANT
 
Philip B. Korsant


 
ZBI EQUITIES, L.L.C.
By: PBK Holdings, Inc., its sole member
 
 
By:
/s/ DAVID GRAY
 
Name:
David Gray
 
Title:
 
Vice President
 
 
 


Page 10 of 10 Pages
 

EXHIBIT A


The undersigned, Ziff Asset Management, L.P., a Delaware limited partnership, PBK Holdings, Inc., a Delaware corporation, Philip B. Korsant, and ZBI Equities, L.L.C., a Delaware limited liability company, hereby agree and acknowledge that the information required by this Schedule 13G, to which this Agreement is attached as an exhibit, is filed on behalf of each of them. The undersigned further agree that any further amendments or supplements thereto shall also be filed on behalf of each of them.

Dated: February 12, 2007

 
ZIFF ASSET MANAGEMENT, L.P.
By: PBK Holdings, Inc., its general partner
 
 
By:
/s/ DAVID GRAY
 
Name:
David Gray
 
Title:
 
Vice President
 
 
PBK HOLDINGS, INC.
 
 
 
By:
/s/ DAVID GRAY
 
Name:
David Gray
 
Title:
 
Vice President
 
   
   
/s/ PHILIP B. KORSANT
 
Philip B. Korsant


 
ZBI EQUITIES, L.L.C.
By: PBK Holdings, Inc., its sole member
 
 
By:
/s/ DAVID GRAY
 
Name:
David Gray
 
Title:
 
Vice President