Driehaus Capital Management LLC
· Exited
Change
−2.9M
Δ Own
−100.0%
Date
Q1 2026
AT
| Investor | Type | Est. change | Change | Δ Own | Date | ||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
|
Driehaus Capital Management LLC
· Exited
Change
−2.9M
Δ Own
−100.0%
Date
Q1 2026
|
Driehaus Capital Management LLC | Exited· Q1 2026 | – | −2.9M | −100.0% | Q1 2026 | |||||
|
Morgan Stanley
· Reduced
Change
−2.7M
Date
Q1 2026
|
Morgan Stanley | Reduced· Q1 2026 | – | −2.7M | – | Q1 2026 | |||||
|
Braidwell LP
· New
Change
+2.2M
Date
Q1 2026
|
Braidwell LP | New· Q1 2026 | – | +2.2M | – | Q1 2026 | |||||
|
Deutsche Bank AG
· Reduced
Change
−2.0M
Date
Q1 2026
|
Deutsche Bank AG | Reduced· Q1 2026 | – | −2.0M | – | Q1 2026 | |||||
|
Two Sigma Advisers, LP
· Exited
Change
−1.6M
Δ Own
−100.0%
Date
Q1 2026
|
Two Sigma Advisers, LP | Exited· Q1 2026 | – | −1.6M | −100.0% | Q1 2026 | |||||
|
Walleye Capital LLC
· Reduced
Change
−1.4M
Date
Q1 2026
|
Walleye Capital LLC | Reduced· Q1 2026 | – | −1.4M | – | Q1 2026 | |||||
|
Point72 Asset Management, L.P.
· Added
Change
+1.4M
Δ Own
+126.7%
Date
Q1 2026
|
Point72 Asset Management, L.P. | Added· Q1 2026 | – | +1.4M | +126.7% | Q1 2026 | |||||
|
Western Standard LLC
· Reduced
Change
−1.2M
Date
Q1 2026
|
Western Standard LLC | Reduced· Q1 2026 | – | −1.2M | – | Q1 2026 | |||||
|
Hood River Capital Management LLC
· Added
Change
+1.2M
Date
Q1 2026
|
Hood River Capital Management LLC | Added· Q1 2026 | – | +1.2M | – | Q1 2026 | |||||
|
Raymond James Financial Inc
· Added
Change
+969K
Date
Q1 2026
|
Raymond James Financial Inc | Added· Q1 2026 | – | +969K | – | Q1 2026 | |||||
|
Oberweis Asset Management Inc/
· Added
Change
+908K
Date
Q1 2026
|
Oberweis Asset Management Inc/ | Added· Q1 2026 | – | +908K | – | Q1 2026 | |||||
|
AQR Capital Management LLC
· Added
Change
+782K
Date
Q1 2026
|
AQR Capital Management LLC | Added· Q1 2026 | – | +782K | – | Q1 2026 | |||||
|
Assenagon Asset Management S.A.
· Reduced
Change
−721K
Date
Q1 2026
|
Assenagon Asset Management S.A. | Reduced· Q1 2026 | – | −721K | – | Q1 2026 | |||||
|
Qube Research & Technologies Ltd
· Added
Change
+682K
Date
Q1 2026
|
Qube Research & Technologies Ltd | Added· Q1 2026 | – | +682K | – | Q1 2026 | |||||
|
M&g PLC
· Exited
Change
−669K
Δ Own
−100.0%
Date
Q1 2026
|
M&g PLC | Exited· Q1 2026 | – | −669K | −100.0% | Q1 2026 | |||||
| Insider | Title | Type | Price | Qty | Value | Owned | ΔOwn | Trade date | Filed date | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
|
McGinnis Karen K.
· Director
Sell
−$48K
|
McGinnis Karen K. | Director | Sell | $8.01 | −6K | −$48K | 95K | – | Jun 11, 2026 | Jun 12, 2026 | |||||||||
|
McGinnis Karen K.
· Director
Grant (A)
32K
|
McGinnis Karen K. | Director | Grant (A) | – | 32K | – | 101K | – | Jun 10, 2026 | Jun 12, 2026 | |||||||||
|
Blackford Quentin S.
· Director
Grant (A)
32K
|
Blackford Quentin S. | Director | Grant (A) | – | 32K | – | 600K | – | Jun 10, 2026 | Jun 12, 2026 | |||||||||
|
Valentine Keith
· Director
Grant (A)
32K
|
Valentine Keith | Director | Grant (A) | – | 32K | – | 264K | – | Jun 10, 2026 | Jun 12, 2026 | |||||||||
|
Pelizzon David R.
· Director
Grant (A)
32K
|
Pelizzon David R. | Director | Grant (A) | – | 32K | – | 379K | – | Jun 10, 2026 | Jun 12, 2026 | |||||||||
|
Demski David M.
· Director
Grant (A)
32K
|
Demski David M. | Director | Grant (A) | – | 32K | – | 432K | – | Jun 10, 2026 | Jun 12, 2026 | |||||||||
|
Berkowitz Mortimer III
· Director
Grant (A)
32K
|
Berkowitz Mortimer III | Director | Grant (A) | – | 32K | – | 650K | – | Jun 10, 2026 | Jun 12, 2026 | |||||||||
|
Valentine Keith
· Director
Buy
+$245K
|
Valentine Keith | Director | Buy | $7.00 | +35K | +$245K | 232K | – | May 11, 2026 | May 11, 2026 | |||||||||
|
Valentine Keith
· Director
Buy
+$331K
|
Valentine Keith | Director | Buy | $7.54 | +44K | +$331K | 197K | – | May 8, 2026 | May 11, 2026 | |||||||||
|
Valentine Keith
· Director
Buy
+$421K
|
Valentine Keith | Director | Buy | $7.49 | +56K | +$421K | 153K | – | May 7, 2026 | May 11, 2026 | |||||||||
|
Marshall Tyson Eliot
· Officer
8 operations
0
|
Marshall Tyson Eliot | Officer | 8 operations | $1.68–$3.34 | 0 | – | 0 | – | Apr 7, 2026 | Apr 9, 2026 | |||||||||
|
Marshall Tyson Eliot
· Officer
Tax withholding or exercise payment (F)
-$258K
|
Marshall Tyson Eliot | Officer | Tax withholding or exercise payment (F) | $11.03 | -23K | -$258K | 639K | – | Apr 7, 2026 | Apr 9, 2026 | |||||||||
|
Koning John Todd
· CFO
Sell
−$986K
|
Koning John Todd | CFO | Sell | $12.36 | −80K | −$986K | 601K | – | Mar 13, 2026 | Mar 17, 2026 | |||||||||
|
Lish Scott
· Officer
Sell
−$3.2M
|
Lish Scott | Officer | Sell | $12.30 | −261K | −$3.2M | 816K | – | Mar 13, 2026 | Mar 17, 2026 | |||||||||
|
Sponsel David
· Officer
Sell
−$2.0M
|
Sponsel David | Officer | Sell | $12.52 | −163K | −$2.0M | 505K | – | Mar 11, 2026 | Mar 13, 2026 | |||||||||
N
A
M
M
G
A
283 reporting institutions disclosed ATEC position changes in the Q1 2026 snapshot.
For each manager, WhoBought compares accepted consecutive 13F share counts. Share change is current shares minus prior shares. Estimated dollar change is that signed share change multiplied by the split-adjusted quarter-mean close. The activity table on this page uses Q1 2026.
An investor crossing 5% of a share class generally files Schedule 13D for activist intent or Schedule 13G for a passive position. The technical form names appear here rather than in the activity rows.
Ownership and institutional activity come from SEC Form 13F filings. Insider activity comes from SEC Form 4, and large-shareholder activity from SEC Schedules 13D and 13G. FMP supplies price data only. Company logos use the local verified Parqet cache with one shared fallback.
Form 13F is a quarterly disclosure and is normally filed after the quarter ends. Every ownership and activity value therefore names its represented period; it is not presented as a live position.
A muted dash marks a missing table value. It means the filing omitted the value, comparable data is unavailable, or no prior position exists for comparison.