Security key
875372203
TANDEM DIABETES CARE INC - Common Stock, par value $0.001 per share (TNDM)
CUSIP: 875372203
Q1 2026 13F Holders as of 31 Mar 2026
- Security type / class
- Equity / Common Stock, par value $0.001 per share
- Total 13F shares
- 78,656,708
- Total 13F value
- $1,508,277,988
- Share change
- +4,610,577
- Put/Call ratio
- 6.5%
- SEC-reported price per share
- $19.17
- Number of holders
- 272
- Value change
- +$81,600,912
- Number of buys
- 134
- Number of sells
- 126
- Shares outstanding
- 68,947,349
Holder snapshot
7 signals
Open additional details 1 more signal available
Security identity
Names, identifiers, and filing context for this profile.
1 source field
Report period
Q1 2026
Institutions
272
Top holders
10
TNDM full security history
Ownership snapshot
Full 13F holder table
TANDEM DIABETES CARE INC SEC filings
TANDEM DIABETES CARE INC company facts
Broader feeds
Ownership snapshot
Top reported holders of TNDM - TANDEM DIABETES CARE INC - Common Stock, par value $0.001 per share (13F + 13D/G + 3/4/5)
Grouped by holder across the latest SEC ownership disclosures. Start with comparable ownership when available, then verify the linked 13F, 13D/G, or 3/4/5 evidence.
Comparable stake leader
BlackRock, Inc.
Disclosed value leader
BlackRock, Inc.
Comparable rows
15/15
Latest evidence
31 Mar 2026
13F
13D/G
Lead comparable stake: 15%
13D/G row: BlackRock, Inc.
Showing 1-6 of 15 holder rows.
Quick read
BlackRock, Inc. leads the comparable SEC ownership view at 15%.
15 of 15 rows have a safely comparable ownership percentage. Use this as a filing-backed starting point, then open the detailed table for source links, reporting role, position value, share count, and filing date.
Open SEC evidence
Opens BlackRock, Inc.'s linked filing trail.
Comparable ownership
Top 5
BlackRock, Inc.
15%
Sessa Capital (Master), L.P.
6.7%
Voya Financial, Inc.
6.3%
VANGUARD PORTFOLIO MANAGEMENT LLC
5.9%
VANGUARD CAPITAL MANAGEMENT LLC
5.2%
Ownership % is shown only when SEC disclosures are safely comparable across share classes.
Detailed SEC evidence table Showing 1-6 of 15 holder rows
| Holder | Evidence | Ownership % | Position | 12M Net Δ | As of |
|---|---|---|---|---|---|
| BlackRock, Inc. |
13F
13D/G
Company
|
15%
from 13D/G
|
$245,058,999
11,149,181 shares
|
— | 31 Dec 2025 |
| Sessa Capital (Master), L.P. |
13D/G
|
6.7%
|
$78,026,383
4,466,307 shares
|
$0 | 31 Mar 2025 |
| Voya Financial, Inc. |
13D/G
|
6.3%
|
$79,402,525
4,343,683 shares
|
$0 | 31 Mar 2026 |
| VANGUARD PORTFOLIO MANAGEMENT LLC |
13D/G
Vanguard Portfolio Management
|
5.9%
|
$77,682,093
4,052,274 shares
|
$0 | 31 Mar 2026 |
| VANGUARD CAPITAL MANAGEMENT LLC |
13D/G
Vanguard Capital Management
|
5.2%
|
$68,125,809
3,553,772 shares
|
$0 | 31 Mar 2026 |
| ArrowMark Colorado Holdings LLC |
13F
13D/G
Company
|
4.3%
from 13D/G
|
$63,515,408
2,889,691 shares
|
— | 31 Dec 2025 |
How to read this table
Rows are grouped by holder and ranked first by SEC-reported ownership % when it is safely comparable, then by disclosed holdings value. — indicates unavailable or non-comparable values; "mixed-class rows" means the latest filing spans non-comparable classes.
13F holder rows
Institutional holders as of Q1 2026
Investor-level positions for this CUSIP, loaded as an interactive table.
Institutions
272
Shares
78,656,708
Rows available
272
| Investor | Option | Weight % | Change % | SEC-reported value | * Price | Shares | Share Change | Activity | Report Period |
|---|
* SEC-reported price is the security price as of the portfolio date and can indicate the last known price at which the security was still held. The marker flags a reported price that did not pass the local price check.
Compare Q1 2026 vs Q1 2026 Across Filers
Q1 2026 holders
272
Q1 2026 holders
272
Holder diff
0
| Investor | Q1 2026 Shares | Q1 2026 Shares | Share Diff | Share Chg % | Q1 2026 value | Q1 2026 value | Value change | Value Chg % |
|---|