UNITED
STATES
SECURITIES
AND EXCHANGE COMMISSION
Washington,
D.C. 20549
|
OMB
APPROVAL
OMB
Number: 3235-0145
Expires:
February 28, 2009
Estimated
average burden
hours
per response 14.5
|
Warren
T. Lazarow, Esq.
O’Melveny
& Myers LLP
2765
Sand Hill Road
Menlo
Park, CA 94025
(650)
473-2600
|
Paul
S. Scrivano, Esq.
O’Melveny
& Myers LLP
Times
Square Tower
7
Times Square
New
York, NY 10036
(212)
326-2000
|
|
1.
|
Names
of Reporting Persons
|
|
Palo
Alto Investors, Inc.
|
|
2.
|
Check
the Appropriate Box if a Member of a Group (See
Instructions)
|
|
|
(a) |
|
|
(b)
|
X
|
|
3.
|
SEC
Use Only
|
|
4.
|
Source
of Funds (See Instructions)
|
AF
|
|
5.
|
Check
if Disclosure of Legal Proceedings Is Required Pursuant to Items 2(d) or
2(e)
____
|
|
6.
|
Citizenship
or Place of Organization
|
California
|
Number
of
Shares
Beneficially
Owned
by
Each
Reporting
Person
With
|
7. Sole
Voting
Power 0
|
8. Shared
Voting
Power 4,674,744
|
|
9. Sole
Dispositive
Power 0
|
|
10. Shared
Dispositive
Power 4,674,744
|
|
11.
|
Aggregate
Amount Beneficially Owned by Each Reporting Person
|
4,674,744
|
|
12.
|
Check
if the Aggregate Amount in Row (11) Excludes Certain Shares
(See Instructions)
|
|
13.
|
Percent
of Class Represented by Amount in Row (11)
9.3%
|
|
14.
|
Type
of Reporting Person (See Instructions)
|
CO,
HC
|
|
1.
|
Names
of Reporting Persons
|
|
Palo
Alto Investors, LLC
|
|
2.
|
Check
the Appropriate Box if a Member of a Group (See
Instructions)
|
|
|
(a) |
|
|
(b)
|
X |
|
3.
|
SEC
Use Only
|
|
4.
|
Source
of Funds (See Instructions)
|
AF
|
|
5.
|
Check
if Disclosure of Legal Proceedings Is Required Pursuant to Items 2(d) or
2(e)
____
|
|
6.
|
Citizenship
or Place of Organization
|
California
|
Number
of
Shares
Beneficially
Owned
by
Each
Reporting
Person
With
|
7. Sole
Voting
Power 0
|
8. Shared
Voting
Power 4,674,744
|
|
9. Sole
Dispositive
Power 0
|
|
10. Shared
Dispositive
Power 4,674,744
|
|
11.
|
Aggregate
Amount Beneficially Owned by Each Reporting Person
|
4,674,744
|
|
12.
|
Check
if the Aggregate Amount in Row (11) Excludes Certain Shares
(See Instructions)
|
|
13.
|
Percent
of Class Represented by Amount in Row (11) 9.3%
|
|
14.
|
Type
of Reporting Person (See Instructions)
|
IA,
OO
|
|
1.
|
Names
of Reporting Persons
|
|
William
Leland Edwards
|
|
2.
|
Check
the Appropriate Box if a Member of a Group (See
Instructions)
|
|
|
(a) |
|
|
(b)
|
X |
|
3.
|
SEC
Use Only
|
|
4.
|
Source
of Funds (See Instructions)
|
AF
|
|
5.
|
Check
if Disclosure of Legal Proceedings Is Required Pursuant to Items 2(d) or
2(e)
____
|
|
6.
|
Citizenship
or Place of Organization
|
USA
|
Number
of
Shares
Beneficially
Owned
by
Each
Reporting
Person
With
|
7. Sole
Voting
Power 28,000
|
8. Shared
Voting
Power 4,674,744
|
|
9. Sole
Dispositive
Power
28,000
|
|
10. Shared
Dispositive
Power
4,674,744
|
|
11.
|
Aggregate
Amount Beneficially Owned by Each Reporting Person
|
4,702,744
|
|
12.
|
Check
if the Aggregate Amount in Row (11) Excludes Certain Shares (See
Instructions)
|
|
13.
|
Percent
of Class Represented by Amount in Row (11) 9.4%
|
|
14.
|
Type
of Reporting Person (See Instructions)
|
IN,
HC
|
|
1.
|
Names
of Reporting Persons
|
|
Anthony
Joonkyoo Yun, MD
|
|
2.
|
Check
the Appropriate Box if a Member of a Group (See
Instructions)
|
|
|
(a) |
|
|
(b)
|
X |
|
3.
|
SEC
Use Only
|
|
4.
|
Source
of Funds (See Instructions)
|
AF
|
|
5.
|
Check
if Disclosure of Legal Proceedings Is Required Pursuant to Items 2(d) or
2(e) ____
|
|
6.
|
Citizenship
or Place of Organization
|
U.S.A.
|
Number
of
Shares
Beneficially
Owned
by
Each
Reporting
Person
With
|
7. Sole
Voting
Power 0
|
8. Shared
Voting
Power 4,674,744
|
|
9. Sole
Dispositive
Power 0
|
|
10. Shared
Dispositive
Power 4,674,744
|
|
11.
|
Aggregate
Amount Beneficially Owned by Each Reporting Person
|
4,674,744
|
|
12.
|
Check
if the Aggregate Amount in Row (11) Excludes Certain Shares (See
Instructions)
|
|
13.
|
Percent
of Class Represented by Amount in Row (11) 9.3%
|
|
14.
|
Type
of Reporting Person (See Instructions)
|
IN,
HC
|
|
1.
|
Names
of Reporting Persons
|
|
Palo
Alto Small Cap Master Fund, L.P.
|
|
2.
|
Check
the Appropriate Box if a Member of a Group (See
Instructions)
|
|
|
(a) |
|
|
(b)
|
X |
|
3.
|
SEC
Use Only
|
|
4.
|
Source
of Funds (See Instructions)
|
AF
|
|
5.
|
Check
if Disclosure of Legal Proceedings Is Required Pursuant to Items 2(d) or
2(e)
____
|
|
6.
|
Citizenship
or Place of Organization
|
Cayman
Islands
|
Number
of
Shares
Beneficially
Owned
by
Each
Reporting
Person
With
|
7. Sole
Voting
Power 0
|
8. Shared
Voting
Power 3,257,172
|
|
9. Sole
Dispositive
Power 0
|
|
10. Shared
Dispositive
Power 3,257,172
|
|
11.
|
Aggregate
Amount Beneficially Owned by Each Reporting Person
|
3,257,172
|
|
12.
|
Check
if the Aggregate Amount in Row (11) Excludes Certain Shares (See
Instructions)
|
|
13.
|
Percent
of Class Represented by Amount in
Row (11) 6.5%
|
|
14.
|
Type
of Reporting Person (See Instructions)
|
PN
|
|
1.
|
Names
of Reporting Persons
|
|
Palo
Alto Small Cap Fund, L.P.
|
|
2.
|
Check
the Appropriate Box if a Member of a Group (See
Instructions)
|
|
|
(a) |
|
|
(b)
|
X |
|
3.
|
SEC
Use Only
|
|
4.
|
Source
of Funds (See Instructions)
|
AF
|
|
5.
|
Check
if Disclosure of Legal Proceedings Is Required Pursuant to Items 2(d) or
2(e)
____
|
|
6.
|
Citizenship
or Place of Organization
|
Delaware
|
Number
of
Shares
Beneficially
Owned
by
Each
Reporting
Person
With
|
7. Sole
Voting
Power 0
|
8. Shared
Voting
Power 2,776,413
|
|
9. Sole
Dispositive
Power 0
|
|
10. Shared
Dispositive
Power 2,776,413
|
|
11.
|
Aggregate
Amount Beneficially Owned by Each Reporting Person
|
2,776,413
|
|
12.
|
Check
if the Aggregate Amount in Row (11) Excludes Certain Shares (See Instructions)
|
|
13.
|
Percent
of Class Represented by Amount
in Row (11)
5.5%
|
|
14.
|
Type
of Reporting Person (See Instructions)
|
PN
|
Exhibit
B
|
Agreement,
dated as of January 12, 2010, between Gastar Exploration Ltd. and Palo
Alto Investors, LLC and certain of its affiliates listed on the signature
pages thereto
|
PALO
ALTO INVESTORS, INC.
By: /s/ Mark
Shamia
Mark
Shamia, Chief Operating Officer
|
PALO
ALTO INVESTORS, LLC
By: /s/ Mark
Shamia
Mark
Shamia, Chief Operating Officer
|
PALO
ALTO SMALL CAP MASTER FUND, L.P.
By: Palo
Alto Investors, LLC, General Partner
By: Palo
Alto Investors, Manager
By: /s/ Mark
Shamia
Mark
Shamia, Chief Operating Officer
|
PALO
ALTO SMALL CAP FUND, L.P.
By: Palo
Alto Investors, LLC, General Partner
By: Palo
Alto Investors, Manager
By: /s/ Mark
Shamia
Mark
Shamia, Chief Operating Officer
|
/s/ Anthony Joonkyoo
Yun
Anthony
Joonkyoo Yun, MD
|
/s/ William Leland
Edwards
William
Leland Edwards
|
Exhibit
|
Exhibit
Name
|
|
A
|
Agreement
Regarding Joint Filing of Statement on Schedule 13D or
13G
|
|
B
|
Agreement,
dated as of January 12, 2010, between Gastar Exploration Ltd. and Palo
Alto Investors, LLC and certain of its affiliates listed on the signature
pages thereto
|
|
By:
|
Palo
Alto Investors, LLC,
|
|
its
general partner
|
|
By:
|
Palo
Alto Investors,
|
|
its
manager
|
|
By:
|
Palo
Alto Investors, LLC,
|
|
its
general partner
|
|
By:
|
Palo
Alto Investors,
|
|
its
manager
|