13G Filing: Billionaire David Shaw’s D. E. Shaw & Co. and AMAG Pharmaceuticals Inc. (AMAG)

Page 2 of 6 SEC Filing

CUSIP No. 00163U106

1.

Names of Reporting Persons

I.R.S. Identification Nos. of above persons (entities only)

D. E. Shaw & Co., L.P.

13-3695715

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

1,729,526

7.

Sole Dispositive Power

-0-

8.

Shared Dispositive Power

1,735,509

9.

Aggregate Amount Beneficially Owned by Each Reporting Person

1,735,509

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)

5.0%

12.

Type of Reporting Person (See Instructions)

IA, PN

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