Nighthawk
Radiology Holdings, Inc.
|
(Name
of Issuer)
|
Common
Stock, $0.001 Par Value Per Share
|
(Title
of Class of Securities)
|
65411N105
|
(CUSIP
Number)
|
March
25, 2008
|
(Date
of Event Which Requires Filing of this
Statement)
|
o | Rule 13d-1(b) |
x | Rule 13d-1(c) |
o | Rule 13d-1(d) |
1
|
NAME
OF REPORTING PERSON
ACCIPITER
LIFE SCIENCES FUND, LP
|
||
2
|
CHECK
THE APPROPRIATE BOX IF A MEMBER OF A GROUP
|
(a) o
(b) o
|
|
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
301,030
shares
|
|
6
|
SHARED
VOTING POWER
0 shares
|
||
7
|
SOLE
DISPOSITIVE POWER
301,030
shares
|
||
8
|
SHARED
DISPOSITIVE POWER
0 shares
|
||
9
|
AGGREGATE
AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
301,030
shares
|
||
10
|
CHECK
BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN
SHARES
|
¨
|
|
11
|
PERCENT
OF CLASS REPRESENTED BY AMOUNT IN ROW (9)
1.0%
|
||
12
|
TYPE
OF REPORTING PERSON
PN
|
1
|
NAME
OF REPORTING PERSON
ACCIPITER
LIFE SCIENCES FUND (OFFSHORE), LTD.
|
||
2
|
CHECK
THE APPROPRIATE BOX IF A MEMBER OF A GROUP
|
(a) o
(b) o
|
|
3
|
SEC
USE ONLY
|
||
4
|
CITIZENSHIP
OR PLACE OF ORGANIZATION
CAYMAN
ISLANDS
|
||
NUMBER
OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH
|
5
|
SOLE
VOTING POWER
305,354
shares
|
|
6
|
SHARED
VOTING POWER
0 shares
|
||
7
|
SOLE
DISPOSITIVE POWER
305,354
shares
|
||
8
|
SHARED
DISPOSITIVE POWER
0 shares
|
||
9
|
AGGREGATE
AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
305,354
shares
|
||
10
|
CHECK
BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN
SHARES
|
¨
|
|
11
|
PERCENT
OF CLASS REPRESENTED BY AMOUNT IN ROW (9)
1.0%
|
||
12
|
TYPE
OF REPORTING PERSON
OO
|
1
|
NAME
OF REPORTING PERSON
ACCIPITER
LIFE SCIENCES FUND II, LP
|
||
2
|
CHECK
THE APPROPRIATE BOX IF A MEMBER OF A GROUP
|
(a) o
(b) o
|
|
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
231,625
shares
|
|
6
|
SHARED
VOTING POWER
0 shares
|
||
7
|
SOLE
DISPOSITIVE POWER
231,625
shares
|
||
8
|
SHARED
DISPOSITIVE POWER
0 shares
|
||
9
|
AGGREGATE
AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
231,625
shares
|
||
10
|
CHECK
BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN
SHARES
|
¨
|
|
11
|
PERCENT
OF CLASS REPRESENTED BY AMOUNT IN ROW (9)
0.8%
|
||
12
|
TYPE
OF REPORTING PERSON
PN
|
1
|
NAME
OF REPORTING PERSON
ACCIPITER
LIFE SCIENCES FUND II (OFFSHORE), LTD.
|
||
2
|
CHECK
THE APPROPRIATE BOX IF A MEMBER OF A GROUP
|
(a) o
(b) o
|
|
3
|
SEC
USE ONLY
|
||
4
|
CITIZENSHIP
OR PLACE OF ORGANIZATION
CAYMAN
ISLANDS
|
||
NUMBER
OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH
|
5
|
SOLE
VOTING POWER
472,633
shares
|
|
6
|
SHARED
VOTING POWER
0 shares
|
||
7
|
SOLE
DISPOSITIVE POWER
472,633
shares
|
||
8
|
SHARED
DISPOSITIVE POWER
0 shares
|
||
9
|
AGGREGATE
AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
472,633
shares
|
||
10
|
CHECK
BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN
SHARES
|
¨
|
|
11
|
PERCENT
OF CLASS REPRESENTED BY AMOUNT IN ROW (9)
1.5%
|
||
12
|
TYPE
OF REPORTING PERSON
OO
|
1
|
NAME
OF REPORTING PERSON
ACCIPITER
LIFE SCIENCES FUND II (QP), LP
|
||
2
|
CHECK
THE APPROPRIATE BOX IF A MEMBER OF A GROUP
|
(a) o
(b) o
|
|
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
253,587
shares
|
|
6
|
SHARED
VOTING POWER
0 shares
|
||
7
|
SOLE
DISPOSITIVE POWER
253,587
shares
|
||
8
|
SHARED
DISPOSITIVE POWER
0 shares
|
||
9
|
AGGREGATE
AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
253,587
shares
|
||
10
|
CHECK
BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN
SHARES
|
¨
|
|
11
|
PERCENT
OF CLASS REPRESENTED BY AMOUNT IN ROW (9)
0.8%
|
||
12
|
TYPE
OF REPORTING PERSON
PN
|
1
|
NAME
OF REPORTING PERSON
CANDENS
CAPITAL, LLC
|
||
2
|
CHECK
THE APPROPRIATE BOX IF A MEMBER OF A GROUP
|
(a) o
(b) o
|
|
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 shares
|
|
6
|
SHARED
VOTING POWER
786,242
shares
|
||
7
|
SOLE
DISPOSITIVE POWER
0 shares
|
||
8
|
SHARED
DISPOSITIVE POWER
786,242
shares
|
||
9
|
AGGREGATE
AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
786,242
shares
|
||
10
|
CHECK
BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN
SHARES
|
¨
|
|
11
|
PERCENT
OF CLASS REPRESENTED BY AMOUNT IN ROW (9)
2.6%
|
||
12
|
TYPE
OF REPORTING PERSON
OO
|
1
|
NAME
OF REPORTING PERSON
ACCIPITER
CAPITAL MANAGEMENT, LLC
|
||
2
|
CHECK
THE APPROPRIATE BOX IF A MEMBER OF A GROUP
|
(a) o
(b) o
|
|
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 shares
|
|
6
|
SHARED
VOTING POWER
777,987
shares
|
||
7
|
SOLE
DISPOSITIVE POWER
0 shares
|
||
8
|
SHARED
DISPOSITIVE POWER
777,987
shares
|
||
9
|
AGGREGATE
AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
777,987
shares
|
||
10
|
CHECK
BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN
SHARES
|
¨
|
|
11
|
PERCENT
OF CLASS REPRESENTED BY AMOUNT IN ROW (9)
2.5%
|
||
12
|
TYPE
OF REPORTING PERSON
OO
|
1
|
NAME
OF REPORTING PERSON
GABE
HOFFMAN
|
||
2
|
CHECK
THE APPROPRIATE BOX IF A MEMBER OF A GROUP
|
(a) o
(b) o
|
|
3
|
SEC
USE ONLY
|
||
4
|
CITIZENSHIP
OR PLACE OF ORGANIZATION
USA
|
||
NUMBER
OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH
|
5
|
SOLE
VOTING POWER
0 shares
|
|
6
|
SHARED
VOTING POWER
1,564,229
shares
|
||
7
|
SOLE
DISPOSITIVE POWER
0 shares
|
||
8
|
SHARED
DISPOSITIVE POWER
1,564,229
shares
|
||
9
|
AGGREGATE
AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
1,564,229
shares
|
||
10
|
CHECK
BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN
SHARES
|
¨
|
|
11
|
PERCENT
OF CLASS REPRESENTED BY AMOUNT IN ROW (9)
5.1%
|
||
12
|
TYPE
OF REPORTING PERSON
IN
|
Item
1(b).
|
Address
of Issuer’s Principal Executive
Offices:
|
Item
2(a).
|
Name
of Person Filing:
|
Item
2(b).
|
Address
of Principal Business Office or, if None,
Residence:
|
Item
2(c).
|
Citizenship:
|
Item
2(d).
|
Title
of Class of Securities:
|
Item
2(e).
|
CUSIP
Number:
|
Item
3.
|
If
This Statement is Filed Pursuant to Rule 13d-1(b), or 13d-2(b) or (c),
Check Whether the Person Filing is
a:
|
|
|
/X/
|
Not
Applicable
|
|
(a)
|
/
/
|
Broker
or dealer registered under Section 15 of the Exchange
Act.
|
|
(b)
|
/
/
|
Bank
as defined in Section 3(a)(6) of the Exchange
Act.
|
|
(c)
|
/
/
|
Insurance
company as defined in Section 3(a)(19) of the Exchange
Act.
|
|
(d)
|
/
/
|
Investment
company registered under Section 8 of the Investment Company
Act.
|
|
(e)
|
/
/
|
An
investment adviser in accordance with Rule
13d-1(b)(1)(ii)(E).
|
|
(f)
|
/
/
|
An
employee benefit plan or endowment fund in accordance with Rule
13d-1(b)(1)(ii)(F).
|
|
(g)
|
/
/
|
A
parent holding company or control person in accordance with Rule
13d-1(b)(1)(ii)(G).
|
|
(h)
|
/
/
|
A
savings association as defined in Section 3(b) of the Federal Deposit
Insurance Act.
|
|
(i)
|
/
/
|
A
church plan that is excluded from the definition of an investment company
under Section 3(c)(14) of the Investment Company
Act.
|
Item
4.
|
Ownership
|
Item
5.
|
Ownership
of Five Percent or Less of a Class.
|
Item
6.
|
Ownership
of More than Five Percent on Behalf of Another
Person.
|
Item
7.
|
Identification
and Classification of the Subsidiary Which Acquired the Security Being
Reported on by the Parent Holding Company or Control
Person.
|
Item
8.
|
Identification
and Classification of Members of the
Group.
|
Item
9.
|
Notice
of Dissolution of Group.
|
Item
10.
|
Certifications.
|
Dated:
April 4, 2008
|
ACCIPITER
LIFE SCIENCES FUND, LP
|
|
By:
|
Candens
Capital, LLC
its
general partner
|
|
By:
|
/s/
Gabe Hoffman
|
|
Gabe
Hoffman, Managing Member
|
ACCIPITER
LIFE SCIENCES FUND II, LP
|
||
By:
|
Candens
Capital, LLC
its
general partner
|
|
By:
|
/s/
Gabe Hoffman
|
|
Gabe
Hoffman, Managing Member
|
ACCIPITER
LIFE SCIENCES FUND (OFFSHORE), LTD.
|
||
By:
|
Accipiter
Capital Management, LLC
its
investment manager
|
|
By:
|
/s/
Gabe Hoffman
|
|
Gabe
Hoffman, Managing Member
|
ACCIPITER
LIFE SCIENCES FUND II (OFFSHORE), LTD.
|
||
By:
|
Accipiter
Capital Management, LLC
its
investment manager
|
|
By:
|
/s/
Gabe Hoffman
|
|
Gabe
Hoffman, Managing Member
|
ACCIPITER
LIFE SCIENCES FUND II (QP), LP
|
||
By:
|
Candens
Capital, LLC
its
general partner
|
|
By:
|
/s/
Gabe Hoffman
|
|
Gabe
Hoffman, Managing Member
|
ACCIPITER
CAPITAL MANAGEMENT, LLC
|
||
By:
|
/s/
Gabe Hoffman
|
|
Gabe
Hoffman, Managing Member
|
CANDENS
CAPITAL, LLC
|
||
By:
|
/s/
Gabe Hoffman
|
|
Gabe
Hoffman, Managing Member
|
/s/
Gabe Hoffman
|
|
GABE
HOFFMAN
|
|
(a)
|
Joint
Filing Agreement dated April 4, 2008 among Accipiter Life Sciences Fund,
LP, Accipiter Life Sciences Fund II, LP, Accipiter Life Sciences Fund
(Offshore), Ltd., Accipiter Life Sciences Fund II (Offshore), Ltd.,
Accipiter Life Sciences Fund II (QP), LP, Accipiter Capital Management,
LLC, Candens Capital, LLC and Gabe
Hoffman.
|
Dated:
April 4, 2008
|
ACCIPITER
LIFE SCIENCES FUND, LP
|
|
By:
|
Candens
Capital, LLC
its
general partner
|
|
By:
|
/s/
Gabe Hoffman
|
|
Gabe
Hoffman, Managing Member
|
ACCIPITER
LIFE SCIENCES FUND II, LP
|
||
By:
|
Candens
Capital, LLC
its
general partner
|
|
By:
|
/s/
Gabe Hoffman
|
|
Gabe
Hoffman, Managing Member
|
ACCIPITER
LIFE SCIENCES FUND (OFFSHORE), LTD.
|
||
By:
|
Accipiter
Capital Management, LLC
its
investment manager
|
|
By:
|
/s/
Gabe Hoffman
|
|
Gabe
Hoffman, Managing Member
|
ACCIPITER
LIFE SCIENCES FUND II (OFFSHORE), LTD.
|
||
By:
|
Accipiter
Capital Management, LLC
its
investment manager
|
|
By:
|
/s/
Gabe Hoffman
|
|
Gabe
Hoffman, Managing Member
|
ACCIPITER
LIFE SCIENCES FUND II (QP), LP
|
||
By:
|
Candens
Capital, LLC
its
general partner
|
|
By:
|
/s/
Gabe Hoffman
|
|
Gabe
Hoffman, Managing Member
|
ACCIPITER
CAPITAL MANAGEMENT, LLC
|
||
By:
|
/s/
Gabe Hoffman
|
|
Gabe
Hoffman, Managing Member
|
CANDENS
CAPITAL, LLC
|
||
By:
|
/s/
Gabe Hoffman
|
|
Gabe
Hoffman, Managing Member
|
/s/
Gabe Hoffman
|
|
GABE
HOFFMAN
|