Ticker · CUSIP 829401108

SION

SIONNA THERAPEUTICS INC

Healthcare·Biotechnology

···Share

Holders (tracked)

Combined shares

5,244,914

Combined value

$215.78M

Last close

$43.54

Quarter

2025Q4

Price is +5.8% vs the avg quarter-end implied price across tracked holders.

Price · 1Y$43.54+32.47 (+293.32%)H $45.24 · L $11.07 · Avg Vol 266K

Insider sellPosition opened

Tracked holders · last 8 quarters

+1 vs previous quarter over the last 4.

SEC event timeline

17 events

ORBIMED ADVISORS LLC
2026-04-16
Sold $10.29M @ $45.34
Insider sell
Thompson Peter A.
2026-04-16
Sold $10.29M @ $45.34
Insider sell
Thompson Peter A.
2026-04-15
Sold $10.53M @ $44.64
Insider sell
ORBIMED ADVISORS LLC
2026-04-15
Sold $10.53M @ $44.64
Insider sell
ORBIMED ADVISORS LLC
2026-04-14
Sold $2.13M @ $44.51
Insider sell
Thompson Peter A.
2026-04-14
Sold $2.13M @ $44.51
Insider sell
D.E. Shaw & Co. opened position2026-02-17
+5,742 shares · 2025Q4
Position
Two Sigma Investments opened position2026-02-17
+6,400 shares · 2025Q4
Position
Ken Griffin (Citadel Advisors) added2026-02-17
+1,051,402 shares · 2025Q4
Position
Izzy Englander (Millennium Mgmt) trimmed2026-02-17
−133,539 shares · 2025Q4
Position
T. Rowe Price added2026-02-17
+193,613 shares · 2025Q4
Position
Wellington Management trimmed2026-02-17
−3,887 shares · 2025Q4
Position
Renaissance Technologies exited2026-02-12
−14,600 shares · 2025Q4
Position
Wellington Management opened position2025-11-14
+42,234 shares · 2025Q3
Position
Izzy Englander (Millennium Mgmt) added2025-11-14
+200,051 shares · 2025Q3
Position
T. Rowe Price trimmed2025-11-14
−223,478 shares · 2025Q3
Position
Renaissance Technologies trimmed2025-11-13
−11,400 shares · 2025Q3
Position

Insider activity

Last 30 days

Net (open-market)

−$45.89M

Buys

0 · $0

Sells

6 · $45.89M

Unique insiders

Date	Insider	Code	Shares	Price	Value
04-16	ORBIMED ADVISORS LLC Director	S	226,906	$45.34	$10.29M
04-16	Thompson Peter A. Director	S	226,906	$45.34	$10.29M
04-15	Thompson Peter A. Director	S	235,863	$44.64	$10.53M
04-15	ORBIMED ADVISORS LLC Director	S	235,863	$44.64	$10.53M
04-14	ORBIMED ADVISORS LLC Director	S	47,814	$44.51	$2.13M
04-14	Thompson Peter A. Director	S	47,814	$44.51	$2.13M

View full insider history for SION →

Follow-the-investor returns

If you'd copied each holder of SION…

Cost basis inferred from each manager's quarter-over-quarter position changes. Sorted by % return on the position they're still holding.

Investor	First in	Cost basis	Return	Position value today
Two Sigma Investments	2025Q1	$10.46	+316.3%	$279K
Andreas Halvorsen (Viking Global)	2025Q1	$10.98	+296.4%	$139.1M
T. Rowe Price	2025Q1	$17.61	+147.3%	$36.2M
Izzy Englander (Millennium Mgmt)	2025Q1	$28.17	+54.6%	$3.5M
Wellington Management	2025Q3	$29.41	+48.0%	$1.7M
Ken Griffin (Citadel Advisors)	2025Q1	$40.13	+8.5%	$47.3M
D.E. Shaw & Co.	2025Q4	$41.14	+5.8%	$250K

Who moved on this name in 2025Q4

Position changes reported for the latest quarter, grouped by direction.

New positions2

Two Sigma Investments
+6,400
$263K
D.E. Shaw & Co.
+5,742
$236K

Added to2

Ken Griffin (Citadel Advisors)
+1,051,402
$43.3M
T. Rowe Price
+193,613
$8K

Trimmed2

Izzy Englander (Millennium Mgmt)
−133,539
$5.5M
Wellington Management
−3,887
$160K

Exited1

Renaissance Technologies
−14,600
$429K

Institutional ownership over time

Distinct super-investors holding this ticker · combined dollar value, by quarter.

Quarter	Holders	Shares	Combined value	Δ holders
2025Q1	5	4,466,253	$46.7M	—
2025Q2	5	4,226,365	$73.3M	—
2025Q3	6	4,139,783	$121.8M	+1
2025Q4	7	5,244,914	$215.8M	+1

Who owns SION

7 super-investors · 2025Q4

Tracked stake

5.24M

Combined value

$216M

% of shares outstanding

—

shares-out unknown

Quarter action mix

New2Added2Trim2Held1

#	Manager	Shares	Value	% of book	Last action	8Q trend
1	Andreas Halvorsen Viking Global	3.20M	$131M	0.3%	Held
2	Ken Griffin Citadel Advisors	1.09M	$45M	0.0%	Added+1.05M
3	T. Rowe Price	831.4K	$34M	0.0%	Added+193.6K
4	Izzy Englander Millennium Mgmt	80.5K	$3M	0.0%	Trim−133.5K
5	Wellington Management	38.3K	$2M	0.0%	Trim−3.9K
6	Two Sigma Investments	6.4K	$263K	0.0%	New+6.4K
7	D.E. Shaw & Co.	5.7K	$236K	0.0%	New+5.7K	—

Recent moves

20 transactions

ADDKen Griffin (Citadel Advisors)
+1,051,402 · 2025Q4
NEWD.E. Shaw & Co.
+5,742 · 2025Q4
NEWTwo Sigma Investments
+6,400 · 2025Q4
TRIMWellington Management
−3,887 · 2025Q4
TRIMIzzy Englander (Millennium Mgmt)
−133,539 · 2025Q4
ADDT. Rowe Price
+193,613 · 2025Q4
SOLDRenaissance Technologies
−14,600 · 2025Q4
NEWWellington Management
+42,234 · 2025Q3
ADDIzzy Englander (Millennium Mgmt)
+200,051 · 2025Q3
TRIMT. Rowe Price
−223,478 · 2025Q3
TRIMRenaissance Technologies
−11,400 · 2025Q3
TRIMIzzy Englander (Millennium Mgmt)
−165,038 · 2025Q2
TRIMT. Rowe Price
−134,974 · 2025Q2
SOLDTwo Sigma Investments
−11,715 · 2025Q2
ADDAndreas Halvorsen (Viking Global)
+242,427 · 2025Q2
NEWRenaissance Technologies
+26,000 · 2025Q2
NEWIzzy Englander (Millennium Mgmt)
+179,072 · 2025Q1
NEWTwo Sigma Investments
+11,715 · 2025Q1
NEWAndreas Halvorsen (Viking Global)
+2,952,754 · 2025Q1
NEWT. Rowe Price
+996,212 · 2025Q1

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