Baker Bros. Advisors’s Spark Therapeutics, Inc. Common Stock ONCE Stock Holding History

Quarter	Market Value	Status	Shares	Shares Change %	Trade Value	Portfolio Weight	Portfolio Position
2019 Q4	–	Sell	-751,927	Closed	-$72.9M	–	114
2019 Q3	$72.9M	Hold	751,927	–	–	0.5%	18
2019 Q2	$77M	Hold	751,927	–	–	0.52%	19
2019 Q1	$85.6M	Sell	751,927 -632,203	-46%	-$72M	0.55%	19
2018 Q4	$54.2M	Hold	1,384,130	–	–	0.44%	21
2018 Q3	$75.5M	Hold	1,384,130	–	–	0.5%	23
2018 Q2	$115M	Hold	1,384,130	–	–	0.86%	12
2018 Q1	$92.2M	Hold	1,384,130	–	–	0.78%	16
2017 Q4	$71.2M	Hold	1,384,130	–	–	0.62%	17
2017 Q3	$123M	Buy	1,384,130 +65,789	+5%	+$5.87M	1%	11
2017 Q2	$78.8M	Hold	1,318,341	–	–	0.69%	13
2017 Q1	$70.3M	Hold	1,318,341	–	–	0.58%	16
2016 Q4	$65.8M	Hold	1,318,341	–	–	0.64%	17
2016 Q3	$79.2M	Hold	1,318,341	–	–	0.72%	15
2016 Q2	$67.4M	Buy	1,318,341 +55,959	+4%	+$2.86M	0.71%	15
2016 Q1	$37.3M	Hold	1,262,382	–	–	0.39%	28
2015 Q4	$57.2M	Hold	1,262,382	–	–	0.47%	26
2015 Q3	$52.7M	Hold	1,262,382	–	–	0.49%	23
2015 Q2	$76.1M	Sell	1,262,382 -65,069	-5%	-$3.92M	0.67%	20
2015 Q1	$103M	Buy	+1,327,451	New	+$103M	0.86%	15