Ticker · CUSIP 65443P102

MASS

908 DEVICES INC

Healthcare·Medical Devices

···Share

Holders (tracked)

Combined shares

3,523,950

Combined value

$18.50M

Last close

$7.42

Quarter

2025Q4

Tracked holders · last 8 quarters

Flat over the last 8 quarters.

Price is +41.3% vs the avg quarter-end implied price across tracked holders.

SEC event timeline

22 events

McCallion Kevin J. · SVP, Products and Production
2026-04-10
Sold $18.9K @ $7.01
Insider sell
Brown Christopher D.
2026-04-10
Sold $124.3K @ $7.07
Insider sell
Brown Christopher D.
2026-04-09
Sold $52.0K @ $7.04
Insider sell
McCallion Kevin J. · SVP, Products and Production
2026-04-09
Sold $38.1K @ $7.03
Insider sell
Brown Christopher D.
2026-04-08
Sold $106.0K @ $7.05
Insider sell
McCallion Kevin J. · SVP, Products and Production
2026-04-08
Sold $131.0K @ $7.05
Insider sell
Izzy Englander (Millennium Mgmt) added2026-02-17
+127,040 shares · 2025Q4
Position
Steve Cohen (Point72) opened position2026-02-17
+55,945 shares · 2025Q4
Position
Ken Griffin (Citadel Advisors) opened position2026-02-17
+264,373 shares · 2025Q4
Position
D.E. Shaw & Co. exited2026-02-17
−25,603 shares · 2025Q4
Position
AQR Capital Management trimmed2026-02-17
−373 shares · 2025Q4
Position
Renaissance Technologies added2026-02-12
+12,800 shares · 2025Q4
Position
Cathie Wood (ARK Invest) added2026-02-11
+32,214 shares · 2025Q4
Position
First Eagle Investment Management added2026-02-04
+19,921 shares · 2025Q4
Position
AQR Capital Management added2025-11-14
+10,187 shares · 2025Q3
Position
Two Sigma Investments added2025-11-14
+1,333 shares · 2025Q3
Position
D.E. Shaw & Co. trimmed2025-11-14
−160,612 shares · 2025Q3
Position
T. Rowe Price added2025-11-14
+1,417 shares · 2025Q3
Position
Izzy Englander (Millennium Mgmt) trimmed2025-11-14
−51,636 shares · 2025Q3
Position
Renaissance Technologies added2025-11-13
+35,200 shares · 2025Q3
Position
First Eagle Investment Management added2025-11-12
+336,584 shares · 2025Q3
Position
Cathie Wood (ARK Invest) trimmed2025-11-12
−694,506 shares · 2025Q3
Position

Insider activity

Last 30 days

Net (open-market)

−$470.2K

Buys

0 · $0

Sells

6 · $470.2K

Unique insiders

Date	Insider	Code	Shares	Price	Value
04-10	Brown Christopher D. Insider	S	17,578	$7.07	$124.3K
04-10	McCallion Kevin J. SVP, Products and Production · Insider	M	2,693	$1.05	$2.8K
04-10	McCallion Kevin J. SVP, Products and Production · Insider	S	2,693	$7.01	$18.9K
04-09	Brown Christopher D. Insider	S	7,392	$7.04	$52.0K
04-09	McCallion Kevin J. SVP, Products and Production · Insider	M	5,420	$1.05	$5.7K
04-09	McCallion Kevin J. SVP, Products and Production · Insider	S	5,420	$7.03	$38.1K
04-08	Brown Christopher D. Insider	S	15,030	$7.05	$106.0K
04-08	McCallion Kevin J. SVP, Products and Production · Insider	M	18,580	$1.05	$19.5K
04-08	McCallion Kevin J. SVP, Products and Production · Insider	S	18,580	$7.05	$131.0K

View full insider history for MASS →

Follow-the-investor returns

If you'd copied each holder of MASS…

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
AQR Capital Management	2023Q3	$5.56	+33.5%	$778K
Ken Griffin (Citadel Advisors)	2021Q4	$5.56	+33.5%	$168K
Ken Griffin (Citadel Advisors)	2021Q4	$5.56	+33.5%	$168K
Izzy Englander (Millennium Mgmt)	2020Q4	$5.64	+31.6%	$1.2M
Steve Cohen (Point72)	2020Q4	$7.47	-0.7%	$415K
Renaissance Technologies	2022Q1	$7.65	-3.0%	$1.6M
First Eagle Investment Management	2025Q2	$7.95	-6.7%	$4.6M
Two Sigma Investments	2021Q1	$10.16	-27.0%	$537K
Cathie Wood (ARK Invest)	2020Q4	$31.10	-76.1%	$14.7M
T. Rowe Price	2020Q4	$52.02	-85.7%	$103K

Who moved on this name in 2025Q4

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

New positions2

Ken Griffin (Citadel Advisors)
+264,373
$1.4M
Steve Cohen (Point72)
+55,945
$294K

Added to4

Izzy Englander (Millennium Mgmt)
+127,040
$667K
Cathie Wood (ARK Invest)
+32,214
$169K
First Eagle Investment Management
+19,921
$105K
Renaissance Technologies
+12,800
$67K

Trimmed1

AQR Capital Management
−373
$2K

Exited1

D.E. Shaw & Co.
−25,603
$224K

Institutional ownership over time

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

Quarter	Holders	Shares	Combined value	Δ holders
2022Q1	7	8,198,784	$155.9M	—
2022Q2	6	6,892,330	$117.7M	-1
2022Q3	7	6,568,148	$108.0M	+1
2022Q4	9	5,933,689	$45.2M	+2
2023Q1	8	6,101,084	$52.5M	-1
2023Q2	7	5,998,732	$41.2M	-1
2023Q3	7	5,879,812	$39.2M	—
2023Q4	8	6,342,673	$71.2M	+1
2024Q1	8	6,432,578	$48.6M	—
2024Q2	9	6,745,439	$34.7M	+1
2024Q3	8	4,136,352	$14.4M	-1
2024Q4	8	3,505,823	$7.7M	—
2025Q1	8	3,581,657	$16.0M	—
2025Q2	9	3,563,066	$25.4M	+1
2025Q3	10	3,068,533	$26.9M	+1
2025Q4	10	3,523,950	$18.5M	—

Who owns MASS

10 super-investors · 2025Q4

Tracked stake

3.52M

Combined value

$19M

% of shares outstanding

—

shares-out unknown

Quarter action mix

New3Added4Trim1Held2

#	Manager	Shares	Value	% of book	Last action
1	Cathie Wood ARK Invest	1.99M	$10M	0.1%	Added+32.2K
2	First Eagle Investment Management	623.9K	$3M	0.0%	Added+19.9K
3	Ken Griffin Citadel Advisors	264.4K	$1M	0.0%	New+264.4K
4	Renaissance Technologies	222.1K	$1M	0.0%	Added+12.8K
5	Izzy Englander Millennium Mgmt	158.1K	$830K	0.0%	Added+127.0K
6	AQR Capital Management	104.8K	$550K	0.0%	Trim−373
7	Two Sigma Investments	72.3K	$380K	0.0%	Held
8	Steve Cohen Point72	55.9K	$294K	0.0%	New+55.9K
9	Ken Griffin Citadel Advisors	22.6K	$119K	0.0%	New+264.4K
10	T. Rowe Price	13.8K	$73K	0.0%	Held

Recent moves

20 transactions

NEWKen Griffin (Citadel Advisors)
+264,373 · 2025Q4
NEWSteve Cohen (Point72)
+55,945 · 2025Q4
ADDIzzy Englander (Millennium Mgmt)
+127,040 · 2025Q4
SOLDD.E. Shaw & Co.
−25,603 · 2025Q4
TRIMAQR Capital Management
−373 · 2025Q4
ADDRenaissance Technologies
+12,800 · 2025Q4
ADDCathie Wood (ARK Invest)
+32,214 · 2025Q4
ADDFirst Eagle Investment Management
+19,921 · 2025Q4
ADDT. Rowe Price
+1,417 · 2025Q3
ADDTwo Sigma Investments
+1,333 · 2025Q3
TRIMIzzy Englander (Millennium Mgmt)
−51,636 · 2025Q3
ADDAQR Capital Management
+10,187 · 2025Q3
TRIMD.E. Shaw & Co.
−160,612 · 2025Q3
ADDRenaissance Technologies
+35,200 · 2025Q3
ADDFirst Eagle Investment Management
+336,584 · 2025Q3
TRIMCathie Wood (ARK Invest)
−694,506 · 2025Q3
TRIMD.E. Shaw & Co.
−153,500 · 2025Q2
NEWIzzy Englander (Millennium Mgmt)
+82,699 · 2025Q2
ADDTwo Sigma Investments
+1,067 · 2025Q2
ADDAQR Capital Management
+13,434 · 2025Q2

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