Ticker · CUSIP 82537J108

SI

SHOULDER INNOVATIONS INC

···Share

Holders (tracked)

Combined shares

123,083

Combined value

$1.76M

Last close

$15.00

Quarter

2025Q4

Price is +4.9% vs the avg quarter-end implied price across tracked holders.

Price · 1Y$15.00-0.05 (-0.33%)H $16.40 · L $11.01 · Avg Vol 106K

Position opened

Tracked holders · last 8 quarters

+2 vs previous quarter over the last 2.

SEC event timeline

3 events

Ken Griffin (Citadel Advisors) trimmed2026-02-17
−31,220 shares · 2025Q4
Position
Izzy Englander (Millennium Mgmt) opened position2026-02-17
+92,003 shares · 2025Q4
Position
Renaissance Technologies opened position2026-02-12
+12,300 shares · 2025Q4
Position

Insider activity

No insider transactions in the last 30 days.

View full insider history for SI →

Follow-the-investor returns

If you'd copied each holder of SI…

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
Ken Griffin (Citadel Advisors)	2025Q3	$12.55	+19.5%	$282K
Renaissance Technologies	2025Q4	$14.30	+4.9%	$185K
Izzy Englander (Millennium Mgmt)	2025Q4	$14.30	+4.9%	$1.4M

Who moved on this name in 2025Q4

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

New positions2

Izzy Englander (Millennium Mgmt)
+92,003
$1.3M
Renaissance Technologies
+12,300
$176K

Added to0

—

Trimmed1

Ken Griffin (Citadel Advisors)
−31,220
$446K

Exited0

—

Institutional ownership over time

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

Quarter	Holders	Shares	Combined value	Δ holders
2025Q3	1	50,000	$628K	—
2025Q4	3	123,083	$1.8M	+2

Who owns SI

3 super-investors · 2025Q4

Tracked stake

123.1K

Combined value

$2M

% of shares outstanding

—

shares-out unknown

Quarter action mix

New2Trim1

#	Manager	Shares	Value	% of book	Last action	8Q trend
1	Izzy Englander Millennium Mgmt	92.0K	$1M	0.0%	New+92.0K	—
2	Ken Griffin Citadel Advisors	18.8K	$269K	0.0%	Trim−31.2K
3	Renaissance Technologies	12.3K	$176K	0.0%	New+12.3K	—

Recent moves

3 transactions

TRIMKen Griffin (Citadel Advisors)
−31,220 · 2025Q4
NEWIzzy Englander (Millennium Mgmt)
+92,003 · 2025Q4
NEWRenaissance Technologies
+12,300 · 2025Q4

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