Seattle Genetics Inc (SGEN): Baker Bros. Advisors Raises Stake

Page 7 of 16 – SEC Filing

SCHEDULE
13D

CUSIP No.  812578102

Page   7   of   16    Pages

1	NAMES OF REPORTING PERSONS FBB3 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 12,678
		8	SHARED VOTING POWER 0
		9	SOLE DISPOSITIVE POWER 12,678
		10	SHARED DISPOSITIVE POWER 0
11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 12,678
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 140,516,451 shares of common stock as of July 20, 2016 as reported in the Issuer’s 10-Q filed with the SEC on July
26, 2016.

Page 7 of 16