Jane Street Group, LLC
· Added
+$51M
Change
+3.9M
Date
Q1 2026
AM
| Investor | Type | Est. change | Change | Δ Own | Date | ||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
|
Jane Street Group, LLC
· Added
+$51M
Change
+3.9M
Date
Q1 2026
|
Jane Street Group, LLC | Added· Q1 2026 | +$51M | +3.9M | – | Q1 2026 | |||||
|
Two Sigma Investments, LP
· Added
+$27M
Change
+2.1M
Δ Own
+144.0%
Date
Q1 2026
|
Two Sigma Investments, LP | Added· Q1 2026 | +$27M | +2.1M | +144.0% | Q1 2026 | |||||
|
Massachusetts Financial Services Co
· New
+$26M
Change
+2.0M
Date
Q1 2026
|
Massachusetts Financial Services Co | New· Q1 2026 | +$26M | +2.0M | – | Q1 2026 | |||||
|
T. Rowe Price Associates
· Added
+$24M
Change
+1.8M
Date
Q1 2026
|
T. Rowe Price Associates | Added· Q1 2026 | +$24M | +1.8M | – | Q1 2026 | |||||
|
Susquehanna International Group, LLP
· Reduced
−$21M
Change
−1.6M
Date
Q1 2026
|
Susquehanna International Group, LLP | Reduced· Q1 2026 | −$21M | −1.6M | – | Q1 2026 | |||||
|
Driehaus Capital Management LLC
· Added
+$18M
Change
+1.4M
Date
Q1 2026
|
Driehaus Capital Management LLC | Added· Q1 2026 | +$18M | +1.4M | – | Q1 2026 | |||||
|
Norges
· Exited
−$17M
Change
−1.3M
Δ Own
−100.0%
Date
Q1 2026
|
Norges | Exited· Q1 2026 | −$17M | −1.3M | −100.0% | Q1 2026 | |||||
|
Marshall Wace, LLP
· New
+$16M
Change
+1.2M
Date
Q1 2026
|
Marshall Wace, LLP | New· Q1 2026 | +$16M | +1.2M | – | Q1 2026 | |||||
|
JPMorgan Chase & Co
· Added
+$15M
Change
+1.1M
Date
Q1 2026
|
JPMorgan Chase & Co | Added· Q1 2026 | +$15M | +1.1M | – | Q1 2026 | |||||
|
Hudson Bay Capital Management LP
· Exited
−$14M
Change
−1.1M
Δ Own
−100.0%
Date
Q1 2026
|
Hudson Bay Capital Management LP | Exited· Q1 2026 | −$14M | −1.1M | −100.0% | Q1 2026 | |||||
|
Deutsche Bank AG
· Reduced
−$14M
Change
−1.1M
Date
Q1 2026
|
Deutsche Bank AG | Reduced· Q1 2026 | −$14M | −1.1M | – | Q1 2026 | |||||
|
D. E. Shaw & Co., Inc.
· New
+$14M
Change
+1.1M
Date
Q1 2026
|
D. E. Shaw & Co., Inc. | New· Q1 2026 | +$14M | +1.1M | – | Q1 2026 | |||||
|
Voloridge Investment Management, LLC
· Reduced
−$14M
Change
−1.1M
Date
Q1 2026
|
Voloridge Investment Management, LLC | Reduced· Q1 2026 | −$14M | −1.1M | – | Q1 2026 | |||||
|
Hrt Financial LP
· New
+$13M
Change
+1.0M
Date
Q1 2026
|
Hrt Financial LP | New· Q1 2026 | +$13M | +1.0M | – | Q1 2026 | |||||
|
Citadel Advisors LLC
· Added
+$13M
Change
+984K
Δ Own
+216.3%
Date
Q1 2026
|
Citadel Advisors LLC | Added· Q1 2026 | +$13M | +984K | +216.3% | Q1 2026 | |||||
| Insider | Title | Type | Price | Qty | Value | Owned | ΔOwn | Trade date | Filed date | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
|
Dixon Donald R.
· Director
Sell
−$1.5M
|
Dixon Donald R. | Director | Sell | $17.17 | −85K | −$1.5M | 359K | – | Jun 15, 2026 | Jun 16, 2026 | |||||||||
|
Bayless Kathleen A.
· Director
Grant (A)
10K
|
Bayless Kathleen A. | Director | Grant (A) | – | 10K | – | 216K | – | Jun 12, 2026 | Jun 16, 2026 | |||||||||
|
Satterthwaite Livingston
· Director
Grant (A)
10K
|
Satterthwaite Livingston | Director | Grant (A) | – | 10K | – | 347K | – | Jun 12, 2026 | Jun 16, 2026 | |||||||||
|
Dixon Donald R.
· Director
Grant (A)
10K
|
Dixon Donald R. | Director | Grant (A) | – | 10K | – | 280K | – | Jun 12, 2026 | Jun 16, 2026 | |||||||||
|
Chu Steven
· Director
Grant (A)
10K
|
Chu Steven | Director | Grant (A) | – | 10K | – | 138K | – | Jun 12, 2026 | Jun 16, 2026 | |||||||||
|
Dixon Donald R.
· Director
Sell
−$765K
|
Dixon Donald R. | Director | Sell | $19.13 | −40K | −$765K | 444K | – | Jun 9, 2026 | Jun 11, 2026 | |||||||||
|
Stepien Thomas M.
· Director
Sell
−$42K
|
Stepien Thomas M. | Director | Sell | $20.97 | −2K | −$42K | 626K | – | Jun 4, 2026 | Jun 5, 2026 | |||||||||
|
Stepien Thomas M.
· Director
3 operations
-30K
|
Stepien Thomas M. | Director | 3 operations | – | -30K | – | 37K | – | Jun 4, 2026 | Jun 5, 2026 | |||||||||
|
Sun Kang
· Director
Sell
−$6K
|
Sun Kang | Director | Sell | $17.19 | −356 | −$6K | 1.3M | – | May 27, 2026 | May 28, 2026 | |||||||||
|
Stepien Thomas M.
· Director
Sell
−$75K
|
Stepien Thomas M. | Director | Sell | $17.19 | −4K | −$75K | 695K | – | May 27, 2026 | May 28, 2026 | |||||||||
|
Stefan Constantin Ionel
· Officer
Sell
−$55K
|
Stefan Constantin Ionel | Officer | Sell | $17.19 | −3K | −$55K | 801K | – | May 27, 2026 | May 28, 2026 | |||||||||
|
Dixon Donald R.
· Director
Sell
−$320K
|
Dixon Donald R. | Director | Sell | $17.90 | −18K | −$320K | 484K | – | May 26, 2026 | May 28, 2026 | |||||||||
|
Sun Kang
· Director
Sell
−$1.0M
|
Sun Kang | Director | Sell | $14.79 | −68K | −$1.0M | 1.3M | – | May 21, 2026 | May 26, 2026 | |||||||||
|
Stefan Constantin Ionel
· Officer
Sell
−$426K
|
Stefan Constantin Ionel | Officer | Sell | $14.79 | −29K | −$426K | 805K | – | May 21, 2026 | May 26, 2026 | |||||||||
|
Stepien Thomas M.
· Director
Sell
−$898K
|
Stepien Thomas M. | Director | Sell | $14.79 | −61K | −$898K | 699K | – | May 21, 2026 | May 26, 2026 | |||||||||
N
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257 reporting institutions disclosed AMPX 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.