$TNDM

$19.22 +$0.32 (1.69%) Close

$TNDM Overview Financial Statements SEC Filings Executives News Red Flags Capital Raising Ownership Insider Transactions Congressional Trades

Ownership

13F as of Q2 2026 · 69.6M shares outstanding

Who owns TNDM?

By type of holder

Institutions 100.0% Insiders 0.0% Everyone else 0.0%

Concentration Top 10 holders own 55.1%

BlackRock, Inc. 16.7% · Sessa Capital IM, L.P. 7.3%

Institutional ownership

100.0%

0 pts vs last qtr

Institutional holders

272

-2 vs last qtr

Net shares bought

−148.1K

by institutions in Q2 2026

New / sold out

48 / 50

positions opened vs closed

How is ownership changing?

Institutions, last 8 quarters

Biggest buyers in Q2 2026

First Light Asset Management, LLC +2.1M
Woodline Partners LP NEW +1.3M

Biggest sellers in Q2 2026

ArrowMark Colorado Holdings LLC −1.8M
Marshall Wace, LLP SOLD OUT −1.4M

Who is planning to sell?

Notices of proposed sale, last 12 months

$23K

6 notices from 1 person

Shares covered

1.3K

0.00% of the company

Arranged in advance

100%

of the value is under a 10b5-1 plan

Under a 10b5-1 plan No plan

Largest proposed sellers

Mark Novara Officer 10b5-1 $23K

Every notice on Red Flags →

A Form 144 is notice of a planned sale, not the sale itself. What insiders actually sold is on Insider Transactions.

Is your stake being diluted?

Diluted share count, FY2019–FY2025

+15.0%

+2.36% a year

Each share's claim on the business

−13.0%

shrank without buying or selling a share

Spent on buybacks vs paid in stock

$30M vs $544M

over 7 fiscal years

Diluted shares, split-adjusted

Buybacks Stock-based comp

How patient are the owners?

Institutional shares by how long they've been held

5+ years48% 3–5 years10% 1–3 years19% Under 1 year24%

Quarterly turnover

19.1%

of institutional shares changed hands

Top 10 managers, median time held

3.5 years

Super Investors

Investment managers reporting TNDM on Form 13F

Holder	Shares	% of company	Change vs last qtr	Held since	% of their book
B BlackRock, Inc.	11.6M	16.65%	+892.3K (+8.3%)	≤2021	0.0%
Shares held by quarter Peak holding12.1M (Q3'25) Change over 8 quarters+472.7K Share of the company16.650% BlackRock, Inc.'s full portfolio →
SC Sessa Capital IM, L.P.	5.1M	7.33%	+369.2K (+7.8%)	2025	1.3%
Shares held by quarter Peak holding5.1M (Q2'26) Change over 8 quarters+5.1M Share of the company7.330% Sessa Capital IM, L.P.'s full portfolio →

BlackRock, Inc.

11.6M

% of company

16.65%

Change vs last qtr

+892.3K (+8.3%)

Held since

≤2021

Sessa Capital IM, L.P.

5.1M

% of company

7.33%

Change vs last qtr

+369.2K (+7.8%)

Held since

2025

28 more super investors behind a free account

See every manager holding Tandem Diabetes Care, Inc., how their position has changed, and how long they've held it.

Institutional Funds

Mutual funds and ETFs reporting TNDM on Form N-PORT; together they hold 37.9% of the company

Fund	Position value	Shares	% of company	% of the fund	As of
IC iShares Core S&P Small-Cap ETF iShares Trust	$62.3M	4.1M	5.94%	0.06%	June 30, 2026
VT Vanguard Total Stock Market Index Fund Vanguard Index Funds	$33M	2.2M	3.14%	0.00%	June 30, 2026

iShares Core S&P Small-Cap ETF

iShares Trust

Position value

$62.3M

% of company

5.94%

% of the fund

0.06%

As of

June 30, 2026

Vanguard Total Stock Market Index Fund

Vanguard Index Funds

Position value

$33M

% of company

3.14%

% of the fund

0.00%

As of

June 30, 2026

23 more funds behind a free account

See every fund holding Tandem Diabetes Care, Inc. and how much of the fund the position is.

Insiders and 5%+ holders

From Forms 3/4/5 and Schedules 13D/G

Holder	Shares	% of company	Change vs last qtr	8 quarters	Held since	% of their book
BK Blickenstaff Kim D Insider	2.0M	2.88%	—	—	—	—
Insider holdings come from Form 3/4/5 filings, which are not quarterly. Share of the company2.880% Blickenstaff Kim D's insider activity →
SJ Sheridan John F Insider	160.3K	0.23%	—	—	—	—
Insider holdings come from Form 3/4/5 filings, which are not quarterly. Share of the company0.230% Sheridan John F's insider activity →

Blickenstaff Kim D

Insider

2.0M

% of company

2.88%

Change vs last qtr

—

Held since

—

Sheridan John F

Insider

160.3K

% of company

0.23%

Change vs last qtr

—

Held since

—

15 more holders behind a free account

See every insider and 5%+ holder of Tandem Diabetes Care, Inc..

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