Security record · archived quarter
AMPH
Amphastar Pharmaceuticals, Inc. · Healthcare · Drug Manufacturers - Specialty & Generic
19Tracked holders
0Δ holders
15.63MShares held
$416.60MReported value
+0New positions
−0Exits
Momentum inputs (comparable managers): holder breadth 0.0% · share flow +1.5% · net new positions 0.0% — formula
All ownership figures: tracked 13F managers only, common-stock positions, reporting period Q3 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 · Q3 2025
| # | Manager | Shares | Δ shares | Value | Their weight | Held | ||
|---|---|---|---|---|---|---|---|---|
| 1 | BlackRock ✦ (passive) | 5.49M | -3.2% | $146.18M | 0.0% | ▼ Trim | 2 | SEC ↗ |
| 2 | BlackRock ✦ (passive) | 5.49M | -3.2% | $146.18M | 0.0% | ▼ Trim | 2 | SEC ↗ |
| 3 | BlackRock ✦ (passive) | 5.49M | -3.2% | $146.18M | 0.0% | ▼ Trim | 2 | SEC ↗ |
| 4 | BlackRock ✦ (passive) | 5.49M | -3.2% | $146.18M | 0.0% | ▼ Trim | 2 | SEC ↗ |
| 5 | BlackRock ✦ (passive) | 5.49M | -3.2% | $146.18M | 0.0% | ▼ Trim | 2 | SEC ↗ |
| 6 | BlackRock ✦ (passive) | 5.49M | -3.2% | $146.18M | 0.0% | ▼ Trim | 2 | SEC ↗ |
| 7 | BlackRock ✦ (passive) | 5.49M | -3.2% | $146.18M | 0.0% | ▼ Trim | 2 | SEC ↗ |
| 8 | BlackRock ✦ (passive) | 5.49M | -3.2% | $146.18M | 0.0% | ▼ Trim | 2 | SEC ↗ |
| 9 | BlackRock ✦ (passive) | 5.49M | -3.2% | $146.18M | 0.0% | ▼ Trim | 2 | SEC ↗ |
| 10 | BlackRock ✦ (passive) | 5.49M | -3.2% | $146.18M | 0.0% | ▼ Trim | 2 | SEC ↗ |
| 11 | BlackRock ✦ (passive) | 5.49M | -3.2% | $146.18M | 0.0% | ▼ Trim | 2 | SEC ↗ |
| 12 | BlackRock ✦ (passive) | 5.49M | -3.2% | $146.18M | 0.0% | ▼ Trim | 2 | SEC ↗ |
| 13 | BlackRock ✦ (passive) | 5.49M | -3.2% | $146.18M | 0.0% | ▼ Trim | 2 | SEC ↗ |
| 14 | BlackRock ✦ (passive) | 5.49M | -3.2% | $146.18M | 0.0% | ▼ Trim | 2 | SEC ↗ |
| 15 | BlackRock ✦ (passive) | 5.49M | -3.2% | $146.18M | 0.0% | ▼ Trim | 2 | SEC ↗ |
| 16 | The Vanguard Group ✦ (passive) | 2.63M | -2.1% | $70.12M | 0.0% | ▼ Trim | 2 | SEC ↗ |
| 17 | The Vanguard Group ✦ (passive) | 2.63M | -2.1% | $70.12M | 0.0% | ▼ Trim | 2 | SEC ↗ |
| 18 | The Vanguard Group ✦ (passive) | 2.63M | -2.1% | $70.12M | 0.0% | ▼ Trim | 2 | SEC ↗ |
| 19 | The Vanguard Group ✦ (passive) | 2.63M | -2.1% | $70.12M | 0.0% | ▼ Trim | 2 | SEC ↗ |
| 20 | The Vanguard Group ✦ (passive) | 2.63M | -2.1% | $70.12M | 0.0% | ▼ Trim | 2 | SEC ↗ |
| 21 | The Vanguard Group ✦ (passive) | 2.63M | -2.1% | $70.12M | 0.0% | ▼ Trim | 2 | SEC ↗ |
| 22 | State Street Global Advisors ✦ (passive) | 1.50M | -4.8% | $39.99M | 0.0% | ▼ Trim | 4 | SEC ↗ |
| 23 | Geode Capital Management ✦ (passive) | 922.58K | -5.2% | $24.59M | 0.0% | ▼ Trim | 6 | SEC ↗ |
| 24 | Geode Capital Management ✦ (passive) | 922.58K | -5.2% | $24.59M | 0.0% | ▼ Trim | 6 | SEC ↗ |
| 25 | Marshall Wace ✦ | 874.07K | +3.0% | $23.29M | 0.0% | ▲ Add | 6 | SEC ↗ |
| 26 | Marshall Wace ✦ | 874.07K | +3.0% | $23.29M | 0.0% | ▲ Add | 6 | SEC ↗ |
| 27 | Marshall Wace ✦ | 874.07K | +3.0% | $23.29M | 0.0% | ▲ Add | 6 | SEC ↗ |
| 28 | Millennium Management ✦ | 697.76K | +12.7% | $18.60M | 0.0% | ▲ Add | 6 | SEC ↗ |
| 29 | Renaissance Technologies ✦ | 586.90K | +1.8% | $15.64M | 0.0% | ▲ Add | 6 | SEC ↗ |
| 30 | Morgan Stanley ✦ | 574.68K | — | $15.32M | 0.0% | n/c | 1 | SEC ↗ |
| 31 | Morgan Stanley ✦ | 574.68K | — | $15.32M | 0.0% | n/c | 1 | SEC ↗ |
| 32 | Morgan Stanley ✦ | 574.68K | — | $15.32M | 0.0% | n/c | 1 | SEC ↗ |
| 33 | Morgan Stanley ✦ | 574.68K | — | $15.32M | 0.0% | n/c | 1 | SEC ↗ |
| 34 | Morgan Stanley ✦ | 574.68K | — | $15.32M | 0.0% | n/c | 1 | SEC ↗ |
| 35 | Morgan Stanley ✦ | 574.68K | — | $15.32M | 0.0% | n/c | 1 | SEC ↗ |
| 36 | Morgan Stanley ✦ | 574.68K | — | $15.32M | 0.0% | n/c | 1 | SEC ↗ |
| 37 | Morgan Stanley ✦ | 574.68K | — | $15.32M | 0.0% | n/c | 1 | SEC ↗ |
| 38 | Morgan Stanley ✦ | 574.68K | — | $15.32M | 0.0% | n/c | 1 | SEC ↗ |
| 39 | Morgan Stanley ✦ | 574.68K | — | $15.32M | 0.0% | n/c | 1 | SEC ↗ |
| 40 | Morgan Stanley ✦ | 574.68K | — | $15.32M | 0.0% | n/c | 1 | SEC ↗ |
| 41 | D. E. Shaw & Co. ✦ | 517.22K | +76.0% | $13.78M | 0.0% | ▲ Add | 5 | SEC ↗ |
| 42 | D. E. Shaw & Co. ✦ | 517.22K | +76.0% | $13.78M | 0.0% | ▲ Add | 5 | SEC ↗ |
| 43 | JPMorgan Chase ✦ | 506.46K | — | $13.50M | 0.0% | n/c | 1 | SEC ↗ |
| 44 | JPMorgan Chase ✦ | 506.46K | — | $13.50M | 0.0% | n/c | 1 | SEC ↗ |
| 45 | JPMorgan Chase ✦ | 506.46K | — | $13.50M | 0.0% | n/c | 1 | SEC ↗ |
| 46 | JPMorgan Chase ✦ | 506.46K | — | $13.50M | 0.0% | n/c | 1 | SEC ↗ |
| 47 | JPMorgan Chase ✦ | 506.46K | — | $13.50M | 0.0% | n/c | 1 | SEC ↗ |
| 48 | JPMorgan Chase ✦ | 506.46K | — | $13.50M | 0.0% | n/c | 1 | SEC ↗ |
| 49 | JPMorgan Chase ✦ | 506.46K | — | $13.50M | 0.0% | n/c | 1 | SEC ↗ |
| 50 | JPMorgan Chase ✦ | 506.46K | — | $13.50M | 0.0% | n/c | 1 | SEC ↗ |
| 51 | JPMorgan Chase ✦ | 506.46K | — | $13.50M | 0.0% | n/c | 1 | SEC ↗ |
| 52 | JPMorgan Chase ✦ | 506.46K | — | $13.50M | 0.0% | n/c | 1 | SEC ↗ |
| 53 | JPMorgan Chase ✦ | 506.46K | — | $13.50M | 0.0% | n/c | 1 | SEC ↗ |
| 54 | JPMorgan Chase ✦ | 506.46K | — | $13.50M | 0.0% | n/c | 1 | SEC ↗ |
| 55 | JPMorgan Chase ✦ | 506.46K | — | $13.50M | 0.0% | n/c | 1 | SEC ↗ |
| 56 | JPMorgan Chase ✦ | 506.46K | — | $13.50M | 0.0% | n/c | 1 | SEC ↗ |
| 57 | JPMorgan Chase ✦ | 506.46K | — | $13.50M | 0.0% | n/c | 1 | SEC ↗ |
| 58 | JPMorgan Chase ✦ | 506.46K | — | $13.50M | 0.0% | n/c | 1 | SEC ↗ |
| 59 | Arrowstreet Capital ✦ | 392.31K | +382.9% | $10.46M | 0.0% | ▲ Add | 2 | SEC ↗ |
| 60 | T. Rowe Price ✦ | 275.22K | +0.7% | $7.34M | 0.0% | ▲ Add | 6 | SEC ↗ |
| 61 | T. Rowe Price ✦ | 275.22K | +0.7% | $7.34M | 0.0% | ▲ Add | 6 | SEC ↗ |
| 62 | Goldman Sachs Group ✦ | 241.23K | — | $6.43M | 0.0% | n/c | 1 | SEC ↗ |
| 63 | Goldman Sachs Group ✦ | 241.23K | — | $6.43M | 0.0% | n/c | 1 | SEC ↗ |
| 64 | Goldman Sachs Group ✦ | 241.23K | — | $6.43M | 0.0% | n/c | 1 | SEC ↗ |
| 65 | Citadel Advisors ✦ | 226.78K | -22.4% | $6.04M | 0.0% | ▼ Trim | 6 | SEC ↗ |
| 66 | Citadel Advisors ✦ | 226.78K | -22.4% | $6.04M | 0.0% | ▼ Trim | 6 | SEC ↗ |
| 67 | Two Sigma Investments ✦ | 98.68K | +23.1% | $2.63M | 0.0% | ▲ Add | 6 | SEC ↗ |
| 68 | AQR Capital Management ✦ | 62.15K | -18.1% | $1.66M | 0.0% | ▼ Trim | 6 | SEC ↗ |
| 69 | AQR Capital Management ✦ | 62.15K | -18.1% | $1.66M | 0.0% | ▼ Trim | 6 | SEC ↗ |
| 70 | AQR Capital Management ✦ | 62.15K | -18.1% | $1.66M | 0.0% | ▼ Trim | 6 | SEC ↗ |
| 71 | AQR Capital Management ✦ | 62.15K | -18.1% | $1.66M | 0.0% | ▼ Trim | 6 | SEC ↗ |
| 72 | Wellington Management ✦ | 17.20K | +10.1% | $458,353 | 0.0% | ▲ Add | 5 | SEC ↗ |
| 73 | Wellington Management ✦ | 17.20K | +10.1% | $458,353 | 0.0% | ▲ Add | 5 | SEC ↗ |
| 74 | Wellington Management ✦ | 17.20K | +10.1% | $458,353 | 0.0% | ▲ Add | 5 | SEC ↗ |
| 75 | Wellington Management ✦ | 17.20K | +10.1% | $458,353 | 0.0% | ▲ Add | 5 | SEC ↗ |
| 76 | Gotham Asset Management ✦ | 15.36K | +9.6% | $409,451 | 0.0% | ▲ Add | 6 | SEC ↗ |
| 77 | Fidelity (FMR) ✦ | 6.47K | -10.2% | $172,486 | 0.0% | ▼ Trim | 2 | SEC ↗ |
| 78 | Fidelity (FMR) ✦ | 6.47K | -10.2% | $172,486 | 0.0% | ▼ Trim | 2 | SEC ↗ |
| 79 | Fidelity (FMR) ✦ | 6.47K | -10.2% | $172,486 | 0.0% | ▼ Trim | 2 | 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
| No tracked exits this quarter. |
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: Q3 2025 ·
Methodology ·
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