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

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Page 6 of 11 SEC Filing

SCHEDULE
13D

CUSIP No.   812578102   Page
  6   of  12  Pages
1

NAMES OF REPORTING PERSONS

FBB2, LLC

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

Delaware

NUMBER OF
SHARES
BENEFICIALLY
OWNED BY
EACH
REPORTING
PERSON
WITH
7

SOLE VOTING POWER

18,243

8

SHARED VOTING POWER

0

9

SOLE DISPOSITIVE POWER

18,243

10

SHARED DISPOSITIVE POWER

0

11

AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

18,243

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)

(1)

14

TYPE OF REPORTING PERSON (See Instructions)

OO

(1) The percentage of ownership is less than 0.1%, 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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