Name of Reporting Persons:

Blackstone Capital Partners (Cayman) IV L.P.

Check the Appropriate Box if a Member of a Group

(a)  ¨        (b)  x

SEC Use Only

Citizenship or Place of Organization:

    Cayman Islands

NUMBER OF

SHARES

BENEFICIALLY

OWNED BY

EACH

REPORTING

PERSON

WITH

Sole Voting Power:

    0

Shared Voting Power:

    118,316,712(1)(2)

Sole Dispositive Power:

    118,316,712

Shared Dispositive Power:

    0

  9.

Aggregate Amount Beneficially Owned by Each Reporting Person:

    118,316,712(1)(2)

10.

Check Box if the Aggregate Amount in Row (9) Excludes Certain Shares (See Instructions)    ¨

11.

Percent of Class Represented by Amount in Row (9):

    30.3%(3)

12.

Type of Reporting Person (See Instructions):

    PN

Name of Reporting Persons:

Blackstone Capital Partners (Cayman) IV-A L.P.

Check the Appropriate Box if a Member of a Group

(a)  ¨        (b)  x

SEC Use Only

Citizenship or Place of Organization:

    Cayman Islands

NUMBER OF

SHARES

BENEFICIALLY

OWNED BY

EACH

REPORTING

PERSON

WITH

Sole Voting Power:

    0

Shared Voting Power:

    1,929,515(1)(2)

Sole Dispositive Power:

    1,929,515

Shared Dispositive Power:

    0

  9.

Aggregate Amount Beneficially Owned by Each Reporting Person:

    1,929,515(1)(2)

10.

Check Box if the Aggregate Amount in Row (9) Excludes Certain Shares (See Instructions)    ¨

11.

Percent of Class Represented by Amount in Row (9):

    0.5%(3)

12.

Type of Reporting Person (See Instructions):

    PN

Name of Reporting Persons:

Blackstone Family Investment Partnership (Cayman) IV-A L.P.

Check the Appropriate Box if a Member of a Group

(a)  ¨        (b)  x

SEC Use Only

Citizenship or Place of Organization:

    Cayman Islands

NUMBER OF

SHARES

BENEFICIALLY

OWNED BY

EACH

REPORTING

PERSON

WITH

Sole Voting Power:

    0

Shared Voting Power:

    3,120,870(1)(2)

Sole Dispositive Power:

    3,120,870

Shared Dispositive Power:

    0

  9.

Aggregate Amount Beneficially Owned by Each Reporting Person:

    3,120,870(1)(2)

10.

Check Box if the Aggregate Amount in Row (9) Excludes Certain Shares (See Instructions)    ¨

11.

Percent of Class Represented by Amount in Row (9):

    0.8%(3)

12.

Type of Reporting Person (See Instructions):

    PN

Name of Reporting Persons:

Blackstone Participation Partnership (Cayman) IV L.P.

Check the Appropriate Box if a Member of a Group

(a)  ¨        (b)  x

SEC Use Only

Citizenship or Place of Organization:

    Cayman Islands

NUMBER OF

SHARES

BENEFICIALLY

OWNED BY

EACH

REPORTING

PERSON

WITH

Sole Voting Power:

    0

Shared Voting Power:

    351,839(1)(2)

Sole Dispositive Power:

    351,839

Shared Dispositive Power:

    0

  9.

Aggregate Amount Beneficially Owned by Each Reporting Person:

    351,839(1)(2)

10.

Check Box if the Aggregate Amount in Row (9) Excludes Certain Shares (See Instructions)    ¨

11.

Percent of Class Represented by Amount in Row (9):

    0.1%(3)

12.

Type of Reporting Person (See Instructions):

    PN

Name of Reporting Persons:

Blackstone Management Associates (Cayman) IV L.P.

Check the Appropriate Box if a Member of a Group

(a)  ¨        (b)  x

SEC Use Only

Citizenship or Place of Organization:

    Cayman Islands

NUMBER OF

SHARES

BENEFICIALLY

OWNED BY

EACH

REPORTING

PERSON

WITH

Sole Voting Power:

    0

Shared Voting Power:

    120,246,227(1)(2)

Sole Dispositive Power:

    120,246,227

Shared Dispositive Power:

    0

  9.

Aggregate Amount Beneficially Owned by Each Reporting Person:

    120,246,227(1)(2)

10.

Check Box if the Aggregate Amount in Row (9) Excludes Certain Shares (See Instructions)    ¨

11.

Percent of Class Represented by Amount in Row (9):

    30.8%(3)

12.

Type of Reporting Person (See Instructions):

    PN

Name of Reporting Persons:

Blackstone Family Investment Partnership (Cayman) IV-A SMD L.P.

Check the Appropriate Box if a Member of a Group

(a)  ¨        (b)  x

SEC Use Only

Citizenship or Place of Organization:

    Cayman Islands

NUMBER OF

SHARES

BENEFICIALLY

OWNED BY

EACH

REPORTING

PERSON

WITH

Sole Voting Power:

    0

Shared Voting Power:

    2,591,244(1)(2)

Sole Dispositive Power:

    2,591,244

Shared Dispositive Power:

    0

  9.

Aggregate Amount Beneficially Owned by Each Reporting Person:

    2,591,244(1)(2)

10.

Check Box if the Aggregate Amount in Row (9) Excludes Certain Shares (See Instructions)    ¨

11.

Percent of Class Represented by Amount in Row (9):

    0.7%(3)

12.

Type of Reporting Person (See Instructions):

    PN

Name of Reporting Persons:

Blackstone Family GP L.L.C.

Check the Appropriate Box if a Member of a Group

(a)  ¨        (b)  x

SEC Use Only

Citizenship or Place of Organization:

    Delaware

NUMBER OF

SHARES

BENEFICIALLY

OWNED BY

EACH

REPORTING

PERSON

WITH

Sole Voting Power:

    0

Shared Voting Power:

    2,591,244(1)(2)

Sole Dispositive Power:

    2,591,244

Shared Dispositive Power:

    0

  9.

Aggregate Amount Beneficially Owned by Each Reporting Person:

    2,591,244(1)(2)

10.

Check Box if the Aggregate Amount in Row (9) Excludes Certain Shares (See Instructions)    ¨

11.

Percent of Class Represented by Amount in Row (9):

    0.7%(3)

12.

Type of Reporting Person (See Instructions):

    OO

Name of Reporting Persons:

BCP IV GP L.L.C.

Check the Appropriate Box if a Member of a Group

(a)  ¨        (b)  x

SEC Use Only

Citizenship or Place of Organization:

    Delaware

NUMBER OF

SHARES

BENEFICIALLY

OWNED BY

EACH

REPORTING

PERSON

WITH

Sole Voting Power:

    0

Shared Voting Power:

    3,472,709(1)(2)

Sole Dispositive Power:

    123,718,936

Shared Dispositive Power:

    0

  9.

Aggregate Amount Beneficially Owned by Each Reporting Person:

    123,718,936(1)(2)

10.

Check Box if the Aggregate Amount in Row (9) Excludes Certain Shares (See Instructions)    ¨

11.

Percent of Class Represented by Amount in Row (9):

    31.7%(3)

12.

Type of Reporting Person (See Instructions):

    OO

Name of Reporting Persons:

Blackstone LR Associates (Cayman) IV Ltd.

Check the Appropriate Box if a Member of a Group

(a)  ¨        (b)  x

SEC Use Only

Citizenship or Place of Organization:

    Cayman Islands

NUMBER OF

SHARES

BENEFICIALLY

OWNED BY

EACH

REPORTING

PERSON

WITH

Sole Voting Power:

    0

Shared Voting Power:

    120,246,227(1)(2)

Sole Dispositive Power:

    0

Shared Dispositive Power:

    0

  9.

Aggregate Amount Beneficially Owned by Each Reporting Person:

    120,246,227(1)(2)

10.

Check Box if the Aggregate Amount in Row (9) Excludes Certain Shares (See Instructions)    ¨

11.

Percent of Class Represented by Amount in Row (9):

    30.8%(3)

12.

Type of Reporting Person (See Instructions):

    OO

Name of Reporting Persons:

Blackstone Holdings III L.P.

Check the Appropriate Box if a Member of a Group

(a)  ¨        (b)  x

SEC Use Only

Citizenship or Place of Organization:

    Quebec, Canada

NUMBER OF

SHARES

BENEFICIALLY

OWNED BY

EACH

REPORTING

PERSON

WITH

Sole Voting Power:

    0

Shared Voting Power:

    123,718,936(1)(2)

Sole Dispositive Power:

    123,718,936

Shared Dispositive Power:

    0

  9.

Aggregate Amount Beneficially Owned by Each Reporting Person:

    123,718,936(1)(2)

10.

Check Box if the Aggregate Amount in Row (9) Excludes Certain Shares (See Instructions)    ¨

11.

Percent of Class Represented by Amount in Row (9):

    31.7%(3)

12.

Type of Reporting Person (See Instructions):

    PN

Name of Reporting Persons:

Blackstone Holdings III GP L.P.

Check the Appropriate Box if a Member of a Group

(a)  ¨        (b)  x

SEC Use Only

Citizenship or Place of Organization:

    Delaware

NUMBER OF

SHARES

BENEFICIALLY

OWNED BY

EACH

REPORTING

PERSON

WITH

Sole Voting Power:

    0

Shared Voting Power:

    123,718,936(1)(2)

Sole Dispositive Power:

    123,718,936

Shared Dispositive Power:

    0

  9.

Aggregate Amount Beneficially Owned by Each Reporting Person:

    123,718,936(1)(2)

10.

Check Box if the Aggregate Amount in Row (9) Excludes Certain Shares (See Instructions)    ¨

11.

Percent of Class Represented by Amount in Row (9):

    31.7%(3)

12.

Type of Reporting Person (See Instructions):

    PN

Name of Reporting Persons:

Blackstone Holdings III GP Management L.L.C.

Check the Appropriate Box if a Member of a Group

(a)  ¨        (b)  x

SEC Use Only

Citizenship or Place of Organization:

    Delaware

NUMBER OF

SHARES

BENEFICIALLY

OWNED BY

EACH

REPORTING

PERSON

WITH

Sole Voting Power:

    0

Shared Voting Power:

    123,718,936(1)(2)

Sole Dispositive Power:

    123,718,936

Shared Dispositive Power:

    0

  9.

Aggregate Amount Beneficially Owned by Each Reporting Person:

    123,718,936(1)(2)

10.

Check Box if the Aggregate Amount in Row (9) Excludes Certain Shares (See Instructions)    ¨

11.

Percent of Class Represented by Amount in Row (9):

    31.7%(3)

12.

Type of Reporting Person (See Instructions):

    OO

Name of Reporting Persons:

The Blackstone Group L.P.

Check the Appropriate Box if a Member of a Group

(a)  ¨        (b)  x

SEC Use Only

Citizenship or Place of Organization:

    Delaware

NUMBER OF

SHARES

BENEFICIALLY

OWNED BY

EACH

REPORTING

PERSON

WITH

Sole Voting Power:

    0

Shared Voting Power:

    123,718,936(1)(2)

Sole Dispositive Power:

    123,718,936

Shared Dispositive Power:

    0

  9.

Aggregate Amount Beneficially Owned by Each Reporting Person:

    123,718,936(1)(2)

10.

Check Box if the Aggregate Amount in Row (9) Excludes Certain Shares (See Instructions)    ¨

11.

Percent of Class Represented by Amount in Row (9):

    31.7%(3)*

12.

Type of Reporting Person (See Instructions):

    PN

Name of Reporting Persons:

Blackstone Group Management L.L.C.

Check the Appropriate Box if a Member of a Group

(a)  ¨        (b)  x

SEC Use Only

Citizenship or Place of Organization:

    Delaware

NUMBER OF

SHARES

BENEFICIALLY

OWNED BY

EACH

REPORTING

PERSON

WITH

Sole Voting Power:

    0

Shared Voting Power:

    123,718,936(1)(2)

Sole Dispositive Power:

    123,718,936

Shared Dispositive Power:

    0

  9.

Aggregate Amount Beneficially Owned by Each Reporting Person:

    123,718,936(1)(2)

10.

Check Box if the Aggregate Amount in Row (9) Excludes Certain Shares (See Instructions)    ¨

11.

Percent of Class Represented by Amount in Row (9):

    31.7%(3)

12.

Type of Reporting Person (See Instructions):

    OO

Name of Reporting Persons:

Steven A. Schwarzman

Check the Appropriate Box if a Member of a Group

(a)  ¨        (b)  x

SEC Use Only

Citizenship or Place of Organization:

    United States

NUMBER OF

SHARES

BENEFICIALLY

OWNED BY

EACH

REPORTING

PERSON

WITH

Sole Voting Power:

    0

Shared Voting Power:

    126,310,180(1)(2)

Sole Dispositive Power:

    126,310,180

Shared Dispositive Power:

    0

  9.

Aggregate Amount Beneficially Owned by Each Reporting Person:

    126,310,180(1)(2)

10.

Check Box if the Aggregate Amount in Row (9) Excludes Certain Shares (See Instructions)    ¨

11.

Percent of Class Represented by Amount in Row (9):

    32.7%(3)

12.

Type of Reporting Person (See Instructions):

    IN

(a).

(b).

(a).

(b).

(c).

(i) Blackstone Capital Partners (Cayman) IV L.P.

c/o The Blackstone Group L.P.

345 Park Avenue

New York, NY 10154

Citizenship: Cayman Islands

(ii) Blackstone Capital Partners (Cayman) IV-A L.P.

c/o The Blackstone Group L.P.

345 Park Avenue

New York, NY 10154

Citizenship: Cayman Islands

(iii) Blackstone Family Investment Partnership (Cayman) IV-A L.P.

c/o The Blackstone Group L.P.

345 Park Avenue

New York, NY 10154

Citizenship: Cayman Islands

(iv) Blackstone Participation Partnership (Cayman) IV L.P.

c/o The Blackstone Group L.P.

345 Park Avenue

New York, NY 10154

Citizenship: Cayman Islands

(v) Blackstone Management Associates (Cayman) IV L.P.

c/o The Blackstone Group L.P.

345 Park Avenue

New York, NY 10154

Citizenship: Cayman Islands

(vi) Blackstone Family Investment Partnership (Cayman) IV-A SMD L.P.

c/o The Blackstone Group L.P.

345 Park Avenue

New York, NY 10154

Citizenship: Cayman Islands

(vii) Blackstone Family GP L.L.C.

c/o The Blackstone Group L.P.

345 Park Avenue

New York, NY 10154

Citizenship: State of Delaware

(viii) BCP IV GP L.L.C.

c/o The Blackstone Group L.P.

345 Park Avenue

New York, NY 10154

Citizenship: State of Delaware

(ix) Blackstone LR Associates (Cayman) IV Ltd.

c/o The Blackstone Group L.P.

345 Park Avenue

New York, NY 10154

Citizenship: Cayman Islands

(x) Blackstone Holdings III L.P.

c/o The Blackstone Group L.P.

345 Park Avenue

New York, NY 10154

Citizenship: Quebec, Canada

(xi) Blackstone Holdings III GP L.P.

c/o The Blackstone Group L.P.

345 Park Avenue

New York, NY 10154

Citizenship: State of Delaware

(xii) Blackstone Holdings III GP Management L.L.C.

c/o The Blackstone Group L.P.

345 Park Avenue

New York, NY 10154

Citizenship: State of Delaware

(xiii) The Blackstone Group L.P.

345 Park Avenue

New York, NY 10154

Citizenship: State of Delaware

(xiv) Blackstone Group Management L.L.C.

c/o The Blackstone Group L.P.

345 Park Avenue

New York, NY 10154

Citizenship: State of Delaware

(xv) Steven A. Schwarzman

c/o The Blackstone Group L.P.

345 Park Avenue

New York, NY 10154

Citizenship: United States

The foregoing persons are hereinafter sometimes collectively referred to as the “Reporting Persons.”

Blackstone Capital Partners (Cayman) IV L.P. (“BCP Cayman IV”) directly holds 118,316,712 Common Shares. Blackstone Capital Partners (Cayman) IV-A L.P. (“BCP Cayman IV-A”) directly holds 1,929,515 Common Shares. Blackstone Family Investment Partnership (Cayman) IV-A L.P. (“BFIP”) directly holds 3,120,870 Common Shares. Blackstone Family Investment Partnership (Cayman) IV-A SMD L.P. (“BFIP SMD”) directly holds 2,591,244 Common Shares. Blackstone Participation Partnership (Cayman) IV L.P. (“BPP”, together with BCP Cayman IV, BCP Cayman IV-A, BFIP and BFIP SMD, the “Blackstone Funds”) directly holds 351,839 Common Shares.

The general partner of BFIP SMD is Blackstone Family GP L.L.C., which is wholly owned by Blackstone’s senior managing directors and controlled by Mr. Stephen A. Schwarzman, its founder. The general partner of BCP Cayman IV and BCP Cayman IV-A is Blackstone Management Associates (Cayman) IV L.P. (“BMA”). Blackstone LR Associates (Cayman) IV Ltd (“BLRA”) and BCP IV GP L.L.C (“BCP IV”) are the general partners of BMA. BCP IV is the general partner of BFIP and BPP. Blackstone Holdings III L.P. is the sole member of BCP IV. The general partner of Blackstone Holdings III L.P. is Blackstone Holdings III GP L.P. The general partner of Blackstone Holdings III GP L.P. is Blackstone Holdings III GP Management L.L.C. The sole member of Blackstone Holdings III GP Management L.L.C. is The Blackstone Group L.P. The general partner of The Blackstone Group L.P. is Blackstone Group Management L.L.C. Blackstone Group Management L.L.C. is wholly owned by Blackstone’s senior managing directors and controlled by its founder, Stephen A. Schwarzman. Mr. Stephen A. Schwarzman is director and controlling person of BLRA.

Each of such Blackstone entities and Mr. Schwarzman may be deemed to beneficially own the Common Shares beneficially owned by the Blackstone Funds directly or indirectly controlled by it or him, but each disclaims beneficial ownership of such Common Shares.

(d).

(e).

As of December 31, 2011, each of the Reporting Persons may be deemed to be the beneficial owner of the Common Shares listed on such Reporting Person’s respective reporting page. BCP Cayman IV directly holds 118,316,712 Common Shares. BCP Cayman IV-A directly holds 1,929,515 Common Shares. BFIP directly holds 3,120,870 Common Shares. BFIP SMD directly holds 2,591,244 Common Shares. BPP directly holds 351,839 Common Shares.

The Quarterly Report on Form 10-Q of the Company for the period ended September 30, 2011, filed with the Securities and Exchange Commission on November 10, 2011, indicated that there were 389,867,068 outstanding Common Shares as of November 1, 2011. Based on this number of outstanding Common Shares, each of the Reporting Persons may be deemed to be the beneficial owner of the percentage of shares of the total number of outstanding Common Shares as listed on such Reporting Person’s respective reporting page.

If this statement is being filed to report the fact that as of the date hereof the reporting person has ceased to be the beneficial owner of more than five percent of the class of securities, check the following:  ¨

Not Applicable.

Not Applicable.

(1) The Reporting Persons are making this single, joint filing because they may be deemed to constitute a “group” within the meaning of Section 13(d)(3) of the Act. The Joint Filing Agreement among the Reporting Persons to file this Schedule 13G jointly in accordance with Rule 13d-1(k) of the Act is attached hereto as Exhibit 99.1.

(2) Given the terms of the Shareholders Agreement (the “Shareholders Agreement”) dated May 10, 2011 among the Company and each of the Blackstone Investors (as defined below) and the Warburg Pincus Investors (as defined below), each of the Reporting Persons may be deemed to be a member of a “group” within the meaning of Section 13(d)(3) of the Act. Each Reporting Person expressly disclaims beneficial ownership with respect to any Common Shares other than the Common Shares owned of record by such Reporting Person.

Investor Funds

Blackstone Investors

1.      Blackstone Capital Partners (Cayman) IV L.P.

2.      Blackstone Capital Partners (Cayman) IV-A L.P.

3.      Blackstone Family Investment Partnership (Cayman) IV-A L.P.

4.      Blackstone Family Investment Partnership (Cayman) IV-A SMD L.P.

5.      Blackstone Participation Partnership (Cayman) IV L.P.

Warburg Pincus Investors

1.      Warburg Pincus International Partners, L.P.

2.      Warburg Pincus Netherlands International Partners I, C.V.

3.      WP-WPIP Investors, L.P.

4.      Warburg Pincus Private Equity VIII, L.P.

5.      Warburg Pincus Netherlands Private Equity VIII I, C.V.

6.      WP-WP VIII Investors, L.P.

Not Applicable.

Not Applicable.