AMPH
Amphastar Pharmaceuticals, Inc. · Healthcare · Drug Manufacturers - Specialty & Generic
Momentum inputs (comparable managers):
holder breadth +20.0% ·
share flow -12.9% ·
net new positions +16.7%
— formula
Ownership fragmentation — more holders, smaller aggregate stake
All ownership figures: tracked 13F managers only, common-stock positions, reporting period Q3 2024
| 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 | — | — |
| # | Manager | Shares | Δ shares | Value | Their weight | Held | ||
|---|---|---|---|---|---|---|---|---|
| 1 | Geode Capital Management ✦ (passive) | 920.36K | +1.6% | $44.67M | 0.0% | ▲ Add | 2 | SEC ↗ |
| 2 | Geode Capital Management ✦ (passive) | 920.36K | +1.6% | $44.67M | 0.0% | ▲ Add | 2 | SEC ↗ |
| 3 | T. Rowe Price ✦ | 568.89K | -2.6% | $27.61M | 0.0% | ▼ Trim | 2 | SEC ↗ |
| 4 | T. Rowe Price ✦ | 568.89K | -2.6% | $27.61M | 0.0% | ▼ Trim | 2 | SEC ↗ |
| 5 | Marshall Wace ✦ | 568.49K | +150.3% | $27.59M | 0.0% | ▲ Add | 2 | SEC ↗ |
| 6 | Marshall Wace ✦ | 568.49K | +150.3% | $27.59M | 0.0% | ▲ Add | 2 | SEC ↗ |
| 7 | Renaissance Technologies ✦ | 489.40K | -9.0% | $23.75M | 0.0% | ▼ Trim | 2 | SEC ↗ |
| 8 | Millennium Management ✦ | 259.65K | -64.8% | $12.60M | 0.0% | ▼ Trim | 2 | SEC ↗ |
| 9 | Citadel Advisors ✦ | 135.24K | -48.6% | $6.56M | 0.0% | ▼ Trim | 2 | SEC ↗ |
| 10 | Citadel Advisors ✦ | 135.24K | -48.6% | $6.56M | 0.0% | ▼ Trim | 2 | SEC ↗ |
| 11 | Two Sigma Investments ✦ | 98.80K | +2.5% | $4.79M | 0.0% | ▲ Add | 2 | SEC ↗ |
| 12 | AQR Capital Management ✦ | 41.67K | -25.3% | $2.02M | 0.0% | ▼ Trim | 2 | SEC ↗ |
| 13 | AQR Capital Management ✦ | 41.67K | -25.3% | $2.02M | 0.0% | ▼ Trim | 2 | SEC ↗ |
| 14 | AQR Capital Management ✦ | 41.67K | -25.3% | $2.02M | 0.0% | ▼ Trim | 2 | SEC ↗ |
| 15 | Point72 Asset Management ✦ | 38.82K | -83.5% | $1.88M | 0.0% | ▼ Trim | 2 | SEC ↗ |
| 16 | Gotham Asset Management ✦ | 35.74K | +29.1% | $1.73M | 0.0% | ▲ Add | 2 | SEC ↗ |
| 17 | D. E. Shaw & Co. ✦ | 23.66K | New | $1.15M | 0.0% | New | 1 | SEC ↗ |
| 18 | Wellington Management ✦ | 19.72K | New | $957,157 | 0.0% | New | 1 | SEC ↗ |
| 19 | Wellington Management ✦ | 19.72K | New | $957,157 | 0.0% | New | 1 | SEC ↗ |
| 20 | Wellington Management ✦ | 19.72K | New | $957,157 | 0.0% | New | 1 | SEC ↗ |
| 21 | Wellington Management ✦ | 19.72K | New | $957,157 | 0.0% | New | 1 | SEC ↗ |
“Their weight” = the position's share of that manager's reported 13F equity value — the conviction measure. ✦ = curated manager.
New buyers
| D. E. Shaw & Co. | $1.15M | 0.0% |
| Wellington Management | $957,157 | 0.0% |
| Wellington Management | $957,157 | 0.0% |
| Wellington Management | $957,157 | 0.0% |
| Wellington Management | $957,157 | 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.
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)
Director · 7.97K sh · $161,852
Officer, Director · 8.18K sh · $183,886
Awards, exercises and tax withholding are never counted as buys or sales here. Methodology