UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

SCHEDULE 13G

(Rule 13d-102)

x

Rule 13d-1(b)

o

Rule 13d-1(c)

o

Rule 13d-1(d)

CUSIP No. 247361108

1.

Names of Reporting Persons. I.R.S. Identification Nos. of above persons (entities only)
Susquehanna Investment Group

2.

Check the Appropriate Box if a Member of a Group (See Instructions)

(a)

o

(b)

x

3.

SEC Use Only

4.

Citizenship or Place of Organization
Pennsylvania

Number of
Shares
Beneficially
Owned by
Each
Reporting
Person With

5.

Sole Voting Power
7,155,155*

6.

Shared Voting Power
8,573,952*

7.

Sole Dispositive Power
7,155,155*

8.

Shared Dispositive Power
8,573,952*

9.

Aggregate Amount Beneficially Owned by Each Reporting Person
8,573,952*

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)
2.0%**

12.

Type of Reporting Person (See Instructions)
BD, PN

*The reporting persons other than Susquehanna International Group, LLP are independent broker-dealers that are under common control and may be deemed to be a group. For purposes of this report, we have indicated that each reporting person has sole voting and dispositive power with respect to the shares directly owned by it and that the reporting persons have shared voting and dispositive power with respect to all of the shares beneficially owned by all of the reporting persons. Each of the reporting persons disclaims beneficial ownership of shares owned directly by the other reporting persons.

** Based on 429,790,036 shares as reported in the Issuer’s Form 20-F for the quarterly period ended December 31, 2005.

CUSIP No. 247361108

1.

Names of Reporting Persons. I.R.S. Identification Nos. of above persons (entities only)
Susquehanna Securities

2.

Check the Appropriate Box if a Member of a Group (See Instructions)

(a)

o

(b)

x

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
981,100*

6.

Shared Voting Power
8,573,952*

7.

Sole Dispositive Power
981,000*

8.

Shared Dispositive Power
8,573,952*

9.

Aggregate Amount Beneficially Owned by Each Reporting Person
8,573,952*

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)
1.9%**

12.

Type of Reporting Person (See Instructions)
BD, PN

*The reporting persons are independent broker-dealers that are under common control and may be deemed to be a group. For purposes of this report, we have indicated that each reporting person has sole voting and dispositive power with respect to the shares directly owned by it and that the reporting persons have shared voting and dispositive power with respect to all of the shares beneficially owned by all of the reporting persons. Each of the reporting persons disclaims beneficial ownership of shares owned directly by the other reporting persons.

** Based on 429,790,036 shares as reported in the Issuer’s Form 20-F for the year ended December 31, 2005.

CUSIP No. 247361108

1.

Names of Reporting Persons. I.R.S. Identification Nos. of above persons (entities only)
Susquehanna Capital Group

2.

Check the Appropriate Box if a Member of a Group (See Instructions)

(a)

o

(b)

x

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
437,697*

6.

Shared Voting Power
8,573,952*

7.

Sole Dispositive Power
437,697*

8.

Shared Dispositive Power
8,573,952*

9.

Aggregate Amount Beneficially Owned by Each Reporting Person
8,573,952*

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)
2.0%**

12.

Type of Reporting Person (See Instructions)
BD, PN

*The reporting persons are independent broker-dealers that are under common control and may be deemed to be a group. For purposes of this report, we have indicated that each reporting person has sole voting and dispositive power with respect to the shares directly owned by it and that the reporting persons have shared voting and dispositive power with respect to all of the shares beneficially owned by all of the reporting persons. Each of the reporting persons disclaims beneficial ownership of shares owned directly by the other reporting persons.

** Based on 429,790,036 shares as reported in the Issuer’s Form 20-F for the year ended December 31, 2005.

CUSIP No. 247361108

1.

Names of Reporting Persons. I.R.S. Identification Nos. of above persons (entities only)
Susquehanna International Group, LLP

2.

Check the Appropriate Box if a Member of a Group (See Instructions)

(a)

o

(b)

x

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
8,573,952*

7.

Sole Dispositive Power
0

8.

Shared Dispositive Power
8,573,952*

9.

Aggregate Amount Beneficially Owned by Each Reporting Person
8,573,952*

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)
2.0%**

12.

Type of Reporting Person (See Instructions)
HC, PN

*The reporting persons are independent broker-dealers that are under common control and may be deemed to be a group. For purposes of this report, we have indicated that each reporting person has sole voting and dispositive power with respect to the shares directly owned by it and that the reporting persons have shared voting and dispositive power with respect to all of the shares beneficially owned by all of the reporting persons. Each of the reporting persons disclaims beneficial ownership of shares owned directly by the other reporting persons.

** Based on 429,790,036 shares as reported in the Issuer’s Form 20-F for the year ended December 31, 2005.

Item 1.

(a)

Name of Issuer
Elan Corporation, plc  (the “Company”)

(b)

Address of Issuer’s Principal Executive Offices
Treasury Building, Lower Grand Canal Street, Dublin 2, Ireland

Item 2.

(a)

Name of Person Filing
(1) Susquehanna Investment Group (a “Reporting Person”)

(2) Susquehanna Securities (a “Reporting Person”)

(3) Susquehanna Capital Group (a “Reporting Person”)

(4) Susquehanna International Group, LLP (a “Reporting Person”)

(b)

Address of Principal Business Office or, if none, Residence
(1) 401 City Avenue, Suite 220, Bala Cynwyd, PA 19004

(2) 401 City Avenue, Suite 220, Bala Cynwyd, PA 19004

(3) 401 City Avenue, Suite 220, Bala Cynwyd, PA 19004

(4) 401 City Avenue, Suite 220, Bala Cynwyd, PA 19004

(c)

Citizenship
(1) Pennsylvania

(2) Delaware

(3) Delaware

(4) Delaware

(d)

Title of Class of Securities
Common Stock (“Common Stock”)

(e)

CUSIP Number

Item 3.

If this statement is filed pursuant to §§240.13d-1(b) or 240.13d-2(b) or (c), check whether the person filing is a:

(a)

x

Broker or dealer registered under section 15 of the Act (15 U.S.C. 78o).

Susquehanna Investment Group

Susquehanna Securities

Susquehanna Capital Group

(b)

o

Bank as defined in section 3(a)(6) of the Act (15 U.S.C. 78c).

(c)

o

Insurance company as defined in section 3(a)(19) of the Act (15 U.S.C. 78c).

(d)

o

Investment company registered under section 8 of the Investment Company Act of 1940 (15 U.S.C 80a-8).

(e)

o

An investment adviser in accordance with §240.13d-1(b)(1)(ii)(E);

(f)

o

An employee benefit plan or endowment fund in accordance with §240.13d-1(b)(1)(ii)(F);

(g)

x

A parent holding company or control person in accordance with § 240.13d-1(b)(1)(ii)(G);

Susquehanna International Group, LLP

(h)

o

A savings associations as defined in Section 3(b) of the Federal Deposit Insurance Act (12 U.S.C. 1813);

(i)

o

A church plan that is excluded from the definition of an investment company under section 3(c)(14) of the Investment Company Act of 1940 (15 U.S.C. 80a-3);

(j)

o

Group, in accordance with §240.13d-1(b)(1)(ii)(J).

Item 4.

Ownership

Provide the following information regarding the aggregate number and percentage of the class of securities of the issuer identified in Item 1.

(1)

Susquehanna Investment Group

(a)

Amount beneficially owned:   

8,573,952*

(b)

Percent of class:   

2.0%

(c)

Number of shares as to which the person has:

(i)

Sole power to vote or to direct the vote   

7,155,155

(ii)

Shared power to vote or to direct the vote    

8,573,952*

(iii)

Sole power to dispose or to direct the disposition of   

7,155,155

(iv)

Shared power to dispose or to direct the disposition of   

8,573,952*

(2)

Susquehanna Securities

(a)

Amount beneficially owned:   

8,573,952*

(b)

Percent of class:   

2.0%

(c)

Number of shares as to which the person has:

(i)

Sole power to vote or to direct the vote   

981,100

(ii)

Shared power to vote or to direct the vote    

8,573,952*

(iii)

Sole power to dispose or to direct the disposition of   

981,100

(iv)

Shared power to dispose or to direct the disposition of   

8,573,952*

(3)

Susquehanna Capital Group

(a)

Amount beneficially owned:   

8,573,952*

(b)

Percent of class:   

2.0%

(c)

Number of shares as to which the person has:

(i)

Sole power to vote or to direct the vote   

437,697

(ii)

Shared power to vote or to direct the vote    

8,573,952*

(iii)

Sole power to dispose or to direct the disposition of   

437,697

(iv)

Shared power to dispose or to direct the disposition of   

8,573,952*

(4)

Susquehanna International Group, LLP

(a)

Amount beneficially owned:   

8,573,952

(b)

Percent of class:   

2.0%

(c)

Number of shares as to which the person has:

(i)

Sole power to vote or to direct the vote   

0

(ii)

Shared power to vote or to direct the vote    

8,573,952*

(iii)

Sole power to dispose or to direct the disposition of   

0

(iv)

Shared power to dispose or to direct the disposition of   

8,573,952*

Item 5.

Ownership of Five Percent or Less of a Class

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   x.

Item 6.

Ownership of More than Five Percent on Behalf of Another Person

Not applicable

Item 7.

Identification and Classification of the Subsidiary Which Acquired the Security Being Reported on By the Parent Holding Company or Control Person

Not applicable

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 acquired and are held in the ordinary course of business and 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.

Date:   February 12, 2007

Susquehanna Investment Group

By:

/s/ Todd Silverberg

Todd Silverberg, General Counsel

Susquehanna Securities

By:

/s/ Todd Silverberg

Todd Silverberg, General Counsel

Susquehanna Capital Group

By:

/s/ Todd Silverberg

Todd Silverberg, General Counsel

Susquehanna International Group, LLP

By:

/s/ Todd Silverberg

Todd Silverberg, General Counsel

EXHIBIT

DESCRIPTION

A

Joint Filing Agreement, dated December 31, 2005, pursuant to Rule 13d-1(k) between Susquehanna Investment Group, Susquehanna Securities, Susquehanna Capital Group and Susquehanna International Group, LLP.

Date:   February 13, 2006

Susquehanna Investment Group

By:

/s/ Todd Silverberg

Todd Silverberg, General Counsel

Date:   February 13, 2006

Susquehanna Securities

By:

/s/ Todd Silverberg

Todd Silverberg, General Counsel

Date:   February 13, 2006

Susquehanna Capital Group

By:

/s/ Todd Silverberg

Todd Silverberg, General Counsel

Date:   February 13, 2006

Susquehanna International Group, LLP

By:

/s/ Todd Silverberg

Todd Silverberg, General Counsel