13D Filing: Baker Bros. Advisors Buys More Shares of Seattle Genetics Inc (SGEN)

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Page 4 of 11 SEC Filing

SCHEDULE
13D

CUSIP No.   812578102   Page
  4   of  12  Pages
1

NAMES OF REPORTING PERSONS

Julian C. Baker

2 CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (See Instructions)

(a) ¨

 (b) ¨

3

SEC USE ONLY

4

SOURCE OF FUNDS (See Instructions)

OO

5

CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEMS 2(d) OR 2(e)

¨
6

CITIZENSHIP OR PLACE OF ORGANIZATION

United States

NUMBER OF
SHARES
BENEFICIALLY
OWNED BY
EACH
REPORTING
PERSON
WITH
7

SOLE VOTING POWER

39,812,771 (1)

8

SHARED VOTING POWER

0

9

SOLE DISPOSITIVE POWER

39,812,771 (1)

10

SHARED DISPOSITIVE POWER

0

11

AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

39,812,771 (1)

12

CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES (See Instructions)

¨
13

PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)

28.4% (1)(2)

14

TYPE OF REPORTING PERSON (See Instructions)

IN, HC

(1) Includes 110,000 shares of the Issuer’s common stock
underlying 110,000 options.

(2) Based
on 139,932,886 shares of common stock
as of February 16, 2016 as reported in the Issuer’s 10-K filed with the SEC
on February 19, 2016.

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