Eminence Capital, LP
· Reduced
Change
−2.5M
Date
Q1 2026
AT
| Investor | Type | Est. change | Change | Δ Own | Date | ||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
|
Eminence Capital, LP
· Reduced
Change
−2.5M
Date
Q1 2026
|
Eminence Capital, LP | Reduced· Q1 2026 | – | −2.5M | – | Q1 2026 | |||||
|
Neuberger Berman Group LLC
· Added
Change
+1.2M
Date
Q1 2026
|
Neuberger Berman Group LLC | Added· Q1 2026 | – | +1.2M | – | Q1 2026 | |||||
|
Arrowstreet Capital, Limited Partnership
· Added
Change
+659K
Date
Q1 2026
|
Arrowstreet Capital, Limited Partnership | Added· Q1 2026 | – | +659K | – | Q1 2026 | |||||
|
Invesco Ltd.
· Added
Change
+615K
Δ Own
+22.6%
Date
Q1 2026
|
Invesco Ltd. | Added· Q1 2026 | – | +615K | +22.6% | Q1 2026 | |||||
|
FMR LLC
· Added
Change
+518K
Δ Own
+11.7%
Date
Q1 2026
|
FMR LLC | Added· Q1 2026 | – | +518K | +11.7% | Q1 2026 | |||||
|
Allspring Global Investments Holdings, LLC
· Reduced
Change
−483K
Date
Q1 2026
|
Allspring Global Investments Holdings, LLC | Reduced· Q1 2026 | – | −483K | – | Q1 2026 | |||||
|
Assenagon Asset Management S.A.
· Reduced
Change
−453K
Date
Q1 2026
|
Assenagon Asset Management S.A. | Reduced· Q1 2026 | – | −453K | – | Q1 2026 | |||||
|
Parsifal Capital Management, LP
· Reduced
Change
−445K
Date
Q1 2026
|
Parsifal Capital Management, LP | Reduced· Q1 2026 | – | −445K | – | Q1 2026 | |||||
|
Jane Street Group, LLC
· Added
Change
+416K
Date
Q1 2026
|
Jane Street Group, LLC | Added· Q1 2026 | – | +416K | – | Q1 2026 | |||||
|
Qube Research & Technologies Ltd
· Added
Change
+407K
Date
Q1 2026
|
Qube Research & Technologies Ltd | Added· Q1 2026 | – | +407K | – | Q1 2026 | |||||
|
Healthcare of Ontario Pension Plan Trust Fund
· Added
Change
+401K
Date
Q1 2026
|
Healthcare of Ontario Pension Plan Trust Fund | Added· Q1 2026 | – | +401K | – | Q1 2026 | |||||
|
Morgan Stanley
· Reduced
Change
−386K
Date
Q1 2026
|
Morgan Stanley | Reduced· Q1 2026 | – | −386K | – | Q1 2026 | |||||
|
Medina Value Partners, LLC
· Reduced
Change
−286K
Date
Q1 2026
|
Medina Value Partners, LLC | Reduced· Q1 2026 | – | −286K | – | Q1 2026 | |||||
|
Nomura Asset Management International Inc.
· New
Change
+284K
Date
Q1 2026
|
Nomura Asset Management International Inc. | New· Q1 2026 | – | +284K | – | Q1 2026 | |||||
|
William Blair Investment Management, LLC
· Reduced
Change
−256K
Date
Q1 2026
|
William Blair Investment Management, LLC | Reduced· Q1 2026 | – | −256K | – | Q1 2026 | |||||
| Insider | Title | Type | Price | Qty | Value | Owned | ΔOwn | Trade date | Filed date | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
|
Swan Renee
· Officer
Sell
−$116K
|
Swan Renee | Officer | Sell | $45.25 | −3K | −$116K | 51K | – | Jun 1, 2026 | Jun 2, 2026 | |||||||||
|
Masters Charles
· Officer
Sell
−$131K
|
Masters Charles | Officer | Sell | $45.25 | −3K | −$131K | 44K | – | Jun 1, 2026 | Jun 2, 2026 | |||||||||
|
Kienzler Jack
· CFO
Sell
−$232K
|
Kienzler Jack | CFO | Sell | $45.25 | −5K | −$232K | 76K | – | Jun 1, 2026 | Jun 2, 2026 | |||||||||
|
Disher Stephanie
· Director
Sell
−$1.2M
|
Disher Stephanie | Director | Sell | $45.25 | −26K | −$1.2M | 363K | – | Jun 1, 2026 | Jun 2, 2026 | |||||||||
|
Carpenter Kevin N.
· Officer
Grant (A)
29K
|
Carpenter Kevin N. | Officer | Grant (A) | – | 29K | – | 29K | – | May 12, 2026 | May 13, 2026 | |||||||||
|
Sharp Heath
· Director
Grant (A)
3K
|
Sharp Heath | Director | Grant (A) | – | 3K | – | 6K | – | May 12, 2026 | May 13, 2026 | |||||||||
|
Macadam Stephen E.
· Director
Grant (A)
3K
|
Macadam Stephen E. | Director | Grant (A) | – | 3K | – | 39K | – | May 12, 2026 | May 13, 2026 | |||||||||
|
Leipold Jane A.
· Director
Grant (A)
3K
|
Leipold Jane A. | Director | Grant (A) | – | 3K | – | 21K | – | May 12, 2026 | May 13, 2026 | |||||||||
|
Taylor Stuart A. II
· Director
Grant (A)
3K
|
Taylor Stuart A. II | Director | Grant (A) | – | 3K | – | 12K | – | May 12, 2026 | May 13, 2026 | |||||||||
|
Donoso Diego
· Director
Grant (A)
3K
|
Donoso Diego | Director | Grant (A) | – | 3K | – | 12K | – | May 12, 2026 | May 13, 2026 | |||||||||
|
Bennett Roy Edwin
· Director
Grant (A)
3K
|
Bennett Roy Edwin | Director | Grant (A) | – | 3K | – | 19K | – | May 12, 2026 | May 13, 2026 | |||||||||
|
Haggerty Gretchen R.
· Director
3 operations
+$110K
|
Haggerty Gretchen R. | Director | 3 operations | $55.71–$55.74 | +2K | +$110K | 26K | – | May 12, 2026 | May 13, 2026 | |||||||||
|
Haggerty Gretchen R.
· Director
Grant (A)
3K
|
Haggerty Gretchen R. | Director | Grant (A) | – | 3K | – | 28K | – | May 12, 2026 | May 13, 2026 | |||||||||
|
Disher Stephanie
· Director
Grant (A)
31K
|
Disher Stephanie | Director | Grant (A) | – | 31K | – | 389K | – | Apr 1, 2026 | Apr 2, 2026 | |||||||||
|
Kienzler Jack
· CFO
Grant (A)
5K
|
Kienzler Jack | CFO | Grant (A) | – | 5K | – | 81K | – | Apr 1, 2026 | Apr 2, 2026 | |||||||||
N
A
M
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G
A
317 reporting institutions disclosed ATMU 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.