Security record · archived quarter
AMPH
Amphastar Pharmaceuticals, Inc. · Healthcare · Drug Manufacturers - Specialty & Generic
94Tracked holders
-1Δ holders
25.83MShares held
$677.54MReported value
+0New positions
−1Exits
Momentum inputs (comparable managers):
holder breadth -1.1% ·
share flow -0.7% ·
net new positions -1.1%
— formula
Broad distribution — falling shares and fewer holders
All ownership figures: tracked 13F managers only, common-stock positions, reporting period Q4 2025
Ownership over time
| Quarter | Holders | Δ | Shares | Reported value | New | Exits |
|---|---|---|---|---|---|---|
| Q2 2026 | 77 | -4 | 22.11M | $440.50M | +3 | −7 |
| Q1 2026 | 84 | -10 | 23.72M | $457.46M | +4 | −14 |
| Q4 2025 | 94 | -1 | 25.83M | $677.54M | — | −1 |
| Q3 2025 | 19 | 0 | 15.63M | $416.60M | — | — |
| Q2 2025 | 16 | +1 | 14.08M | $323.35M | +1 | — |
| Q1 2025 | 12 | -1 | 5.84M | $169.25M | — | −1 |
| Q4 2024 | 13 | 0 | 4.91M | $182.39M | — | — |
| Q3 2024 | 12 | +2 | 3.20M | $155.33M | +2 | — |
| Q2 2024 | 10 | — | 3.67M | $146.92M | — | — |
Who holds it · Q4 2025
| # | Manager | Shares | Δ shares | Value | Their weight | Held | ||
|---|---|---|---|---|---|---|---|---|
| 1 | BlackRock ✦ (passive) | 5.46M | -0.4% | $146.27M | 0.0% | ▼ Trim | 3 | SEC ↗ |
| 2 | BlackRock ✦ (passive) | 5.46M | -0.4% | $146.27M | 0.0% | ▼ Trim | 3 | SEC ↗ |
| 3 | BlackRock ✦ (passive) | 5.46M | -0.4% | $146.27M | 0.0% | ▼ Trim | 3 | SEC ↗ |
| 4 | BlackRock ✦ (passive) | 5.46M | -0.4% | $146.27M | 0.0% | ▼ Trim | 3 | SEC ↗ |
| 5 | BlackRock ✦ (passive) | 5.46M | -0.4% | $146.27M | 0.0% | ▼ Trim | 3 | SEC ↗ |
| 6 | BlackRock ✦ (passive) | 5.46M | -0.4% | $146.27M | 0.0% | ▼ Trim | 3 | SEC ↗ |
| 7 | BlackRock ✦ (passive) | 5.46M | -0.4% | $146.27M | 0.0% | ▼ Trim | 3 | SEC ↗ |
| 8 | BlackRock ✦ (passive) | 5.46M | -0.4% | $146.27M | 0.0% | ▼ Trim | 3 | SEC ↗ |
| 9 | BlackRock ✦ (passive) | 5.46M | -0.4% | $146.27M | 0.0% | ▼ Trim | 3 | SEC ↗ |
| 10 | BlackRock ✦ (passive) | 5.46M | -0.4% | $146.27M | 0.0% | ▼ Trim | 3 | SEC ↗ |
| 11 | BlackRock ✦ (passive) | 5.46M | -0.4% | $146.27M | 0.0% | ▼ Trim | 3 | SEC ↗ |
| 12 | BlackRock ✦ (passive) | 5.46M | -0.4% | $146.27M | 0.0% | ▼ Trim | 3 | SEC ↗ |
| 13 | BlackRock ✦ (passive) | 5.46M | -0.4% | $146.27M | 0.0% | ▼ Trim | 3 | SEC ↗ |
| 14 | BlackRock ✦ (passive) | 5.46M | -0.4% | $146.27M | 0.0% | ▼ Trim | 3 | SEC ↗ |
| 15 | BlackRock ✦ (passive) | 5.46M | -0.4% | $146.27M | 0.0% | ▼ Trim | 3 | SEC ↗ |
| 16 | The Vanguard Group ✦ (passive) | 2.61M | -0.9% | $69.85M | 0.0% | ▼ Trim | 3 | SEC ↗ |
| 17 | The Vanguard Group ✦ (passive) | 2.61M | -0.9% | $69.85M | 0.0% | ▼ Trim | 3 | SEC ↗ |
| 18 | The Vanguard Group ✦ (passive) | 2.61M | -0.9% | $69.85M | 0.0% | ▼ Trim | 3 | SEC ↗ |
| 19 | The Vanguard Group ✦ (passive) | 2.61M | -0.9% | $69.85M | 0.0% | ▼ Trim | 3 | SEC ↗ |
| 20 | The Vanguard Group ✦ (passive) | 2.61M | -0.9% | $69.85M | 0.0% | ▼ Trim | 3 | SEC ↗ |
| 21 | The Vanguard Group ✦ (passive) | 2.61M | -0.9% | $69.85M | 0.0% | ▼ Trim | 3 | SEC ↗ |
| 22 | Td Asset Management Inc | 1.96M | — | $52.57M | 0.0% | n/c | 1 | SEC ↗ |
| 23 | Dimensional Fund Advisors Lp | 1.80M | — | $48.20M | 0.0% | n/c | 1 | SEC ↗ |
| 24 | Dimensional Fund Advisors Lp | 1.80M | — | $48.20M | 0.0% | n/c | 1 | SEC ↗ |
| 25 | Dimensional Fund Advisors Lp | 1.80M | — | $48.20M | 0.0% | n/c | 1 | SEC ↗ |
| 26 | Dimensional Fund Advisors Lp | 1.80M | — | $48.20M | 0.0% | n/c | 1 | SEC ↗ |
| 27 | Dimensional Fund Advisors Lp | 1.80M | — | $48.20M | 0.0% | n/c | 1 | SEC ↗ |
| 28 | State Street Global Advisors ✦ (passive) | 1.53M | +2.1% | $41.02M | 0.0% | ▲ Add | 5 | SEC ↗ |
| 29 | Marshall Wace ✦ | 1.24M | +41.5% | $33.13M | 0.0% | ▲ Add | 7 | SEC ↗ |
| 30 | Marshall Wace ✦ | 1.24M | +41.5% | $33.13M | 0.0% | ▲ Add | 7 | SEC ↗ |
| 31 | Marshall Wace ✦ | 1.24M | +41.5% | $33.13M | 0.0% | ▲ Add | 7 | SEC ↗ |
| 32 | Geode Capital Management ✦ (passive) | 886.83K | -3.9% | $23.75M | 0.0% | ▼ Trim | 7 | SEC ↗ |
| 33 | Geode Capital Management ✦ (passive) | 886.83K | -3.9% | $23.75M | 0.0% | ▼ Trim | 7 | SEC ↗ |
| 34 | American Century Companies Inc | 665.34K | — | $17.82M | 0.0% | n/c | 1 | SEC ↗ |
| 35 | Morgan Stanley ✦ | 591.63K | +3.0% | $15.84M | 0.0% | ▲ Add | 2 | SEC ↗ |
| 36 | Morgan Stanley ✦ | 591.63K | +3.0% | $15.84M | 0.0% | ▲ Add | 2 | SEC ↗ |
| 37 | Morgan Stanley ✦ | 591.63K | +3.0% | $15.84M | 0.0% | ▲ Add | 2 | SEC ↗ |
| 38 | Morgan Stanley ✦ | 591.63K | +3.0% | $15.84M | 0.0% | ▲ Add | 2 | SEC ↗ |
| 39 | Morgan Stanley ✦ | 591.63K | +3.0% | $15.84M | 0.0% | ▲ Add | 2 | SEC ↗ |
| 40 | Morgan Stanley ✦ | 591.63K | +3.0% | $15.84M | 0.0% | ▲ Add | 2 | SEC ↗ |
| 41 | Morgan Stanley ✦ | 591.63K | +3.0% | $15.84M | 0.0% | ▲ Add | 2 | SEC ↗ |
| 42 | Morgan Stanley ✦ | 591.63K | +3.0% | $15.84M | 0.0% | ▲ Add | 2 | SEC ↗ |
| 43 | Morgan Stanley ✦ | 591.63K | +3.0% | $15.84M | 0.0% | ▲ Add | 2 | SEC ↗ |
| 44 | Morgan Stanley ✦ | 591.63K | +3.0% | $15.84M | 0.0% | ▲ Add | 2 | SEC ↗ |
| 45 | Morgan Stanley ✦ | 591.63K | +3.0% | $15.84M | 0.0% | ▲ Add | 2 | SEC ↗ |
| 46 | Arrowstreet Capital ✦ | 559.43K | +42.6% | $14.98M | 0.0% | ▲ Add | 3 | SEC ↗ |
| 47 | D. E. Shaw & Co. ✦ | 557.07K | +7.7% | $14.92M | 0.0% | ▲ Add | 6 | SEC ↗ |
| 48 | D. E. Shaw & Co. ✦ | 557.07K | +7.7% | $14.92M | 0.0% | ▲ Add | 6 | SEC ↗ |
| 49 | Goldman Sachs Group ✦ | 556.71K | +130.8% | $14.91M | 0.0% | ▲ Add | 2 | SEC ↗ |
| 50 | Goldman Sachs Group ✦ | 556.71K | +130.8% | $14.91M | 0.0% | ▲ Add | 2 | SEC ↗ |
| 51 | Goldman Sachs Group ✦ | 556.71K | +130.8% | $14.91M | 0.0% | ▲ Add | 2 | SEC ↗ |
| 52 | Renaissance Technologies ✦ | 544.70K | -7.2% | $14.59M | 0.0% | ▼ Trim | 7 | SEC ↗ |
| 53 | Invesco Ltd. | 501.40K | — | $13.43M | 0.0% | n/c | 1 | SEC ↗ |
| 54 | Invesco Ltd. | 501.40K | — | $13.43M | 0.0% | n/c | 1 | SEC ↗ |
| 55 | Invesco Ltd. | 501.40K | — | $13.43M | 0.0% | n/c | 1 | SEC ↗ |
| 56 | Invesco Ltd. | 501.40K | — | $13.43M | 0.0% | n/c | 1 | SEC ↗ |
| 57 | Invesco Ltd. | 501.40K | — | $13.43M | 0.0% | n/c | 1 | SEC ↗ |
| 58 | Hotchkis & Wiley Capital Management… | 402.56K | — | $10.78M | 0.0% | n/c | 1 | SEC ↗ |
| 59 | Northern Trust Corp | 371.39K | — | $9.95M | 0.0% | n/c | 1 | SEC ↗ |
| 60 | Northern Trust Corp | 371.39K | — | $9.95M | 0.0% | n/c | 1 | SEC ↗ |
| 61 | Northern Trust Corp | 371.39K | — | $9.95M | 0.0% | n/c | 1 | SEC ↗ |
| 62 | Northern Trust Corp | 371.39K | — | $9.95M | 0.0% | n/c | 1 | SEC ↗ |
| 63 | Northern Trust Corp | 371.39K | — | $9.95M | 0.0% | n/c | 1 | SEC ↗ |
| 64 | Northern Trust Corp | 371.39K | — | $9.95M | 0.0% | n/c | 1 | SEC ↗ |
| 65 | Northern Trust Corp | 371.39K | — | $9.95M | 0.0% | n/c | 1 | SEC ↗ |
| 66 | Charles Schwab Investment… | 350.71K | — | $9.39M | 0.0% | n/c | 1 | SEC ↗ |
| 67 | Victory Capital Management Inc | 305.16K | — | $8.17M | 0.0% | n/c | 1 | SEC ↗ |
| 68 | Millennium Management ✦ | 290.67K | -58.3% | $7.78M | 0.0% | ▼ Trim | 7 | SEC ↗ |
| 69 | Bank of New York Mellon Corp | 559.06K | — | $7.22M | 0.0% | n/c | 1 | SEC ↗ |
| 70 | Bank of New York Mellon Corp | 559.06K | — | $7.22M | 0.0% | n/c | 1 | SEC ↗ |
| 71 | Bank of New York Mellon Corp | 559.06K | — | $7.22M | 0.0% | n/c | 1 | SEC ↗ |
| 72 | Bank of New York Mellon Corp | 559.06K | — | $7.22M | 0.0% | n/c | 1 | SEC ↗ |
| 73 | Bank of New York Mellon Corp | 559.06K | — | $7.22M | 0.0% | n/c | 1 | SEC ↗ |
| 74 | Bank of New York Mellon Corp | 559.06K | — | $7.22M | 0.0% | n/c | 1 | SEC ↗ |
| 75 | Bank of New York Mellon Corp | 559.06K | — | $7.22M | 0.0% | n/c | 1 | SEC ↗ |
| 76 | UBS Group AG | 256.62K | — | $6.87M | 0.0% | n/c | 1 | SEC ↗ |
| 77 | UBS Group AG | 256.62K | — | $6.87M | 0.0% | n/c | 1 | SEC ↗ |
| 78 | UBS Group AG | 256.62K | — | $6.87M | 0.0% | n/c | 1 | SEC ↗ |
| 79 | Citadel Advisors ✦ | 228.72K | +0.9% | $6.13M | 0.0% | ▲ Add | 7 | SEC ↗ |
| 80 | Citadel Advisors ✦ | 228.72K | +0.9% | $6.13M | 0.0% | ▲ Add | 7 | SEC ↗ |
| 81 | Principal Financial Group Inc | 217.97K | — | $5.84M | 0.0% | n/c | 1 | SEC ↗ |
| 82 | Principal Financial Group Inc | 217.97K | — | $5.84M | 0.0% | n/c | 1 | SEC ↗ |
| 83 | Jane Street Group, Llc | 217.54K | — | $5.83M | 0.0% | n/c | 1 | SEC ↗ |
| 84 | Jane Street Group, Llc | 217.54K | — | $5.83M | 0.0% | n/c | 1 | SEC ↗ |
| 85 | Pacer Advisors, Inc. | 177.74K | — | $4.76M | 0.0% | n/c | 1 | SEC ↗ |
| 86 | JPMorgan Chase ✦ | 158.64K | -68.7% | $4.25M | 0.0% | ▼ Trim | 2 | SEC ↗ |
| 87 | JPMorgan Chase ✦ | 158.64K | -68.7% | $4.25M | 0.0% | ▼ Trim | 2 | SEC ↗ |
| 88 | JPMorgan Chase ✦ | 158.64K | -68.7% | $4.25M | 0.0% | ▼ Trim | 2 | SEC ↗ |
| 89 | JPMorgan Chase ✦ | 158.64K | -68.7% | $4.25M | 0.0% | ▼ Trim | 2 | SEC ↗ |
| 90 | JPMorgan Chase ✦ | 158.64K | -68.7% | $4.25M | 0.0% | ▼ Trim | 2 | SEC ↗ |
| 91 | JPMorgan Chase ✦ | 158.64K | -68.7% | $4.25M | 0.0% | ▼ Trim | 2 | SEC ↗ |
| 92 | JPMorgan Chase ✦ | 158.64K | -68.7% | $4.25M | 0.0% | ▼ Trim | 2 | SEC ↗ |
| 93 | First Trust Advisors Lp | 140.31K | — | $3.76M | 0.0% | n/c | 1 | SEC ↗ |
| 94 | Ameriprise Financial Inc | 133.72K | — | $3.58M | 0.0% | n/c | 1 | SEC ↗ |
| 95 | Ameriprise Financial Inc | 133.72K | — | $3.58M | 0.0% | n/c | 1 | SEC ↗ |
| 96 | Nordea Investment Management Ab | 129.14K | — | $3.46M | 0.0% | n/c | 1 | SEC ↗ |
| 97 | Nordea Investment Management Ab | 129.14K | — | $3.46M | 0.0% | n/c | 1 | SEC ↗ |
| 98 | Bank Of America Corp /De/ | 128.17K | — | $3.43M | 0.0% | n/c | 1 | SEC ↗ |
| 99 | Bank Of America Corp /De/ | 128.17K | — | $3.43M | 0.0% | n/c | 1 | SEC ↗ |
| 100 | Bank Of America Corp /De/ | 128.17K | — | $3.43M | 0.0% | n/c | 1 | SEC ↗ |
“Their weight” = the position's share of that manager's reported 13F equity value — the conviction measure. ✦ = curated manager.
New buyers
| No new tracked buyers this quarter. |
Exited
| Wellington Management | $458,353 | was 0.0% |
Full-market context: across ALL 13F filers (SEC structured data, Q1 2026): 5 holders, 1.03M shares, $928,379 reported. This is a different, older period than the tracked-universe figures above and the two are never mixed.
Frequently co-owned
What else this security's tracked holders most often hold — shared-ownership counts, not fundamental relationships.
Open-market purchases (P)
No open-market insider purchases in our coverage window.
Open-market sales (S)
Aug 11
PRINS RICHARD K
Director · 7.97K sh · $161,852
Aug 07
PETERS WILLIAM J
Officer, Director · 8.18K sh · $183,886
Awards, exercises and tax withholding are never counted as buys or sales here. Methodology
Jul 14
SC 13G — DIMENSIONAL FUND ADVISORS LP
Provenance: Ownership from parsed 13F common-stock positions (tracked universe, comparable sets for changes); insider rows from Forms 3/4/5; stakes from Schedules 13D/13G; every filing links to its original on SEC EDGAR.
Reporting period: Q4 2025 ·
Methodology ·
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