Security record · archived quarter
AMPH
Amphastar Pharmaceuticals, Inc. · Healthcare · Drug Manufacturers - Specialty & Generic
16Tracked holders
+1Δ holders
14.08MShares held
$323.35MReported value
+1New positions
−0Exits
Momentum inputs (comparable managers):
holder breadth +6.7% ·
share flow -0.8% ·
net new positions +6.2%
— formula
Ownership fragmentation — more holders, smaller aggregate stake
All ownership figures: tracked 13F managers only, common-stock positions, reporting period Q2 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 · Q2 2025
| # | Manager | Shares | Δ shares | Value | Their weight | Held | ||
|---|---|---|---|---|---|---|---|---|
| 1 | BlackRock ✦ (passive) | 5.67M | — | $130.16M | 0.0% | n/c | 1 | SEC ↗ |
| 2 | BlackRock ✦ (passive) | 5.67M | — | $130.16M | 0.0% | n/c | 1 | SEC ↗ |
| 3 | BlackRock ✦ (passive) | 5.67M | — | $130.16M | 0.0% | n/c | 1 | SEC ↗ |
| 4 | BlackRock ✦ (passive) | 5.67M | — | $130.16M | 0.0% | n/c | 1 | SEC ↗ |
| 5 | BlackRock ✦ (passive) | 5.67M | — | $130.16M | 0.0% | n/c | 1 | SEC ↗ |
| 6 | BlackRock ✦ (passive) | 5.67M | — | $130.16M | 0.0% | n/c | 1 | SEC ↗ |
| 7 | BlackRock ✦ (passive) | 5.67M | — | $130.16M | 0.0% | n/c | 1 | SEC ↗ |
| 8 | BlackRock ✦ (passive) | 5.67M | — | $130.16M | 0.0% | n/c | 1 | SEC ↗ |
| 9 | BlackRock ✦ (passive) | 5.67M | — | $130.16M | 0.0% | n/c | 1 | SEC ↗ |
| 10 | BlackRock ✦ (passive) | 5.67M | — | $130.16M | 0.0% | n/c | 1 | SEC ↗ |
| 11 | BlackRock ✦ (passive) | 5.67M | — | $130.16M | 0.0% | n/c | 1 | SEC ↗ |
| 12 | BlackRock ✦ (passive) | 5.67M | — | $130.16M | 0.0% | n/c | 1 | SEC ↗ |
| 13 | BlackRock ✦ (passive) | 5.67M | — | $130.16M | 0.0% | n/c | 1 | SEC ↗ |
| 14 | BlackRock ✦ (passive) | 5.67M | — | $130.16M | 0.0% | n/c | 1 | SEC ↗ |
| 15 | BlackRock ✦ (passive) | 5.67M | — | $130.16M | 0.0% | n/c | 1 | SEC ↗ |
| 16 | The Vanguard Group ✦ (passive) | 2.69M | — | $61.69M | 0.0% | n/c | 1 | SEC ↗ |
| 17 | The Vanguard Group ✦ (passive) | 2.69M | — | $61.69M | 0.0% | n/c | 1 | SEC ↗ |
| 18 | The Vanguard Group ✦ (passive) | 2.69M | — | $61.69M | 0.0% | n/c | 1 | SEC ↗ |
| 19 | The Vanguard Group ✦ (passive) | 2.69M | — | $61.69M | 0.0% | n/c | 1 | SEC ↗ |
| 20 | The Vanguard Group ✦ (passive) | 2.69M | — | $61.69M | 0.0% | n/c | 1 | SEC ↗ |
| 21 | The Vanguard Group ✦ (passive) | 2.69M | — | $61.69M | 0.0% | n/c | 1 | SEC ↗ |
| 22 | State Street Global Advisors ✦ (passive) | 1.58M | -1.8% | $36.19M | 0.0% | ▼ Trim | 3 | SEC ↗ |
| 23 | Geode Capital Management ✦ (passive) | 973.24K | +1.9% | $22.35M | 0.0% | ▲ Add | 5 | SEC ↗ |
| 24 | Geode Capital Management ✦ (passive) | 973.24K | +1.9% | $22.35M | 0.0% | ▲ Add | 5 | SEC ↗ |
| 25 | Marshall Wace ✦ | 848.68K | -17.7% | $19.49M | 0.0% | ▼ Trim | 5 | SEC ↗ |
| 26 | Marshall Wace ✦ | 848.68K | -17.7% | $19.49M | 0.0% | ▼ Trim | 5 | SEC ↗ |
| 27 | Millennium Management ✦ | 618.98K | -28.7% | $14.21M | 0.0% | ▼ Trim | 5 | SEC ↗ |
| 28 | Renaissance Technologies ✦ | 576.50K | +16.5% | $13.24M | 0.0% | ▲ Add | 5 | SEC ↗ |
| 29 | D. E. Shaw & Co. ✦ | 293.93K | +907.0% | $6.75M | 0.0% | ▲ Add | 4 | SEC ↗ |
| 30 | D. E. Shaw & Co. ✦ | 293.93K | +907.0% | $6.75M | 0.0% | ▲ Add | 4 | SEC ↗ |
| 31 | Citadel Advisors ✦ | 292.35K | +87.4% | $6.71M | 0.0% | ▲ Add | 5 | SEC ↗ |
| 32 | Citadel Advisors ✦ | 292.35K | +87.4% | $6.71M | 0.0% | ▲ Add | 5 | SEC ↗ |
| 33 | T. Rowe Price ✦ | 273.29K | -49.5% | $6.28M | 0.0% | ▼ Trim | 5 | SEC ↗ |
| 34 | T. Rowe Price ✦ | 273.29K | -49.5% | $6.28M | 0.0% | ▼ Trim | 5 | SEC ↗ |
| 35 | Arrowstreet Capital ✦ | 81.24K | New | $1.87M | 0.0% | New | 1 | SEC ↗ |
| 36 | Two Sigma Investments ✦ | 80.13K | +6.4% | $1.84M | 0.0% | ▲ Add | 5 | SEC ↗ |
| 37 | AQR Capital Management ✦ | 75.84K | +41.4% | $1.74M | 0.0% | ▲ Add | 5 | SEC ↗ |
| 38 | AQR Capital Management ✦ | 75.84K | +41.4% | $1.74M | 0.0% | ▲ Add | 5 | SEC ↗ |
| 39 | AQR Capital Management ✦ | 75.84K | +41.4% | $1.74M | 0.0% | ▲ Add | 5 | SEC ↗ |
| 40 | AQR Capital Management ✦ | 75.84K | +41.4% | $1.74M | 0.0% | ▲ Add | 5 | SEC ↗ |
| 41 | AQR Capital Management ✦ | 75.84K | +41.4% | $1.74M | 0.0% | ▲ Add | 5 | SEC ↗ |
| 42 | Wellington Management ✦ | 15.62K | -7.7% | $358,588 | 0.0% | ▼ Trim | 4 | SEC ↗ |
| 43 | Wellington Management ✦ | 15.62K | -7.7% | $358,588 | 0.0% | ▼ Trim | 4 | SEC ↗ |
| 44 | Wellington Management ✦ | 15.62K | -7.7% | $358,588 | 0.0% | ▼ Trim | 4 | SEC ↗ |
| 45 | Wellington Management ✦ | 15.62K | -7.7% | $358,588 | 0.0% | ▼ Trim | 4 | SEC ↗ |
| 46 | Gotham Asset Management ✦ | 14.01K | +28.9% | $321,761 | 0.0% | ▲ Add | 5 | SEC ↗ |
| 47 | Fidelity (FMR) ✦ | 7.20K | — | $165,384 | 0.0% | n/c | 1 | SEC ↗ |
| 48 | Fidelity (FMR) ✦ | 7.20K | — | $165,384 | 0.0% | n/c | 1 | SEC ↗ |
| 49 | Fidelity (FMR) ✦ | 7.20K | — | $165,384 | 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
| Arrowstreet Capital | $1.87M | 0.0% |
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: Q2 2025 ·
Methodology ·
Get this via the API