Baker Bros. Advisors’s Ionis Pharmaceuticals IONS Stock Holding History

Baker Bros. Advisors’s Portfolio IONS Stock Details IONS Fund Activity

Bought

Maintained

Sold

Quarter	Market Value	Status	Shares	Change in Stake	Trade Value	Portfolio Weight	Portfolio Position
2026 Q2	$162M	Hold	2,047,727	–	–	0.81%	21
2026 Q1	$154M	Buy	2,047,727 +255,886	+14%	+$20.2M	0.88%	16
2025 Q4	$142M	Buy	1,791,841 +1,225,043	+216%	+$92.2M	0.83%	17
2025 Q3	$37.1M	Buy	+566,798	New	+$27.7M	0.27%	35
2025 Q2	–	Sell	-357,915	Closed	-$10.8M	–	93
2025 Q1	$10.8M	Hold	357,915	–	–	0.12%	45
2024 Q4	$12.5M	Buy	357,915 +134,445	+60%	+$5.03M	0.13%	49
2024 Q3	$8.95M	Buy	+223,470	New	+$10.4M	0.09%	55
2017 Q1	–	Sell	-57,140	Closed	-$2.73M	–	125
2016 Q4	$2.73M	Hold	57,140	–	–	0.03%	81
2016 Q3	$2.09M	Hold	57,140	–	–	0.02%	95
2016 Q2	$1.33M	Hold	57,140	–	–	0.01%	110
2016 Q1	$2.31M	Hold	57,140	–	–	0.02%	96
2015 Q4	$3.54M	Hold	57,140	–	–	0.03%	88
2015 Q3	$2.31M	Hold	57,140	–	–	0.02%	100
2015 Q2	$3.29M	Hold	57,140	–	–	0.03%	90
2015 Q1	$3.64M	Sell	57,140 -39,163	-41%	-$2.66M	0.03%	86
2014 Q4	$5.95M	Hold	96,303	–	–	0.06%	68
2014 Q3	$3.74M	Hold	96,303	–	–	0.05%	72
2014 Q2	$3.32M	Hold	96,303	–	–	0.04%	79
2014 Q1	$4.16M	Sell	96,303 -150,733	-61%	-$7.31M	0.05%	80
2013 Q4	$9.84M	Hold	247,036	–	–	0.14%	45
2013 Q3	$9.27M	Hold	247,036	–	–	0.13%	46
2013 Q2	$6.64M	Buy	+247,036	New	+$5.25M	0.13%	44

Other funds holding IONS

Fidelity Investments Boston, Massachusetts $2.3T AUM 54.33% 1-Year Est. Return

Capital World Investors Los Angeles, California $846B AUM 46.74% 1-Year Est. Return

BlackRock New York $6.73T AUM 46.02% 1-Year Est. Return

Vanguard Portfolio Management Malvern, Pennsylvania $2.22T AUM

Wellington Management Group Boston, Massachusetts $580B AUM 38.23% 1-Year Est. Return

Vanguard Capital Management Malvern, Pennsylvania $4.68T AUM

Two Sigma Investments New York $138B AUM 41.87% 1-Year Est. Return

Royal Bank of Canada Toronto, Ontario, Canada $672B AUM 33.48% 1-Year Est. Return

State Street Boston, Massachusetts $3.37T AUM 44.26% 1-Year Est. Return

T. Rowe Price Investment Management Baltimore, Maryland $153B AUM 38.14% 1-Year Est. Return

Baker Bros. Advisors's IONS Position: Q2 2026 in Review

Baker Bros. Advisors held its Ionis Pharmaceuticals (IONS) position steady in Q2 2026 at 2,047,727 shares worth $162M. The position accounts for 0.81% of the portfolio, ranked #21.

Baker Bros. Advisors first reported a position in IONS in Q2 2013 and has held it in 22 quarters since. 514 funds tracked by Wall St. Rank hold IONS as of Q2 2026.

Baker Bros. Advisors held 2,047,727 shares of Ionis Pharmaceuticals worth $162M as of Q2 2026.
Baker Bros. Advisors left its Ionis Pharmaceuticals share count unchanged in Q2 2026.
Ionis Pharmaceuticals made up 0.81% of Baker Bros. Advisors's portfolio in Q2 2026, its #21 holding.
Baker Bros. Advisors first reported a position in Ionis Pharmaceuticals in Q2 2013 and has held it in 22 quarters since.
514 funds tracked by Wall St. Rank held Ionis Pharmaceuticals as of Q2 2026.

Based on Baker Bros. Advisors's 13F filing for Q2 2026, filed 14 Aug 2026.