AMPH · Insider trading · 13F holders · Congress trades
Amphastar Pharmaceuticals, Inc. (AMPH)
Who is buying and selling AMPH: company insiders on SEC Form 4, hedge funds and superinvestors on Form 13F, and members of Congress under the STOCK Act. Every figure links to the filing or page it comes from.
- 13F filers holding
- 4
- Insider buys, 90 days
- $0
- Insider sales, 90 days
- $764K
- Congress trades, 12 months
- 0
AMPH at a glance
- Between Aug 1, 2026 and Oct 29, 2026, 3 AMPH insiders filed 5 sales worth $764K on SEC Form 4, and no open-market purchases; 2 of the sales were pre-planned under Rule 10b5-1.
- 4 13F filers hold AMPH among their 50 largest positions, worth $22.1M combined. The biggest bets by portfolio weight are Bridge City Capital, LLC (2.1%), Lam Group, Inc. (1.7%) and Denali Advisors LLC (0.8%). In their latest 13Fs, 0 managers opened a new position and 1 added to one.
- No member of Congress has disclosed a trade in AMPH.
- AMPH last closed at $26.93 on Oct 29, 2026.
AMPH insider trading
Between Aug 1, 2026 and Oct 29, 2026, 3 AMPH insiders filed 5 sales worth $764K on SEC Form 4, and no open-market purchases; 2 of the sales were pre-planned under Rule 10b5-1.
| Filed | Insider | Role | Trade | Shares | Price | Value | Form 4 |
|---|---|---|---|---|---|---|---|
| Sep 23, 2026 | Peters William J | CFO, EVP & TREASURER, Director | Sale10b5-1 | 4,139 | $25.00 | $103K | SEC |
| Sep 17, 2026 | Zhou Rong | SENIOR EVP, PRODUCTION CENTER | Sale | 10,000 | $23.94 | $239K | SEC |
| Sep 3, 2026 | Zhou Rong | SENIOR EVP, PRODUCTION CENTER | Sale | 3,187 | $23.63 | $75K | SEC |
| Aug 12, 2026 | Prins Richard K | Director | Sale | 7,973 | $20.30 | $162K | SEC |
| Aug 11, 2026 | Peters William J | CFO, EVP & TREASURER, Director | Sale10b5-1 | 8,180 | $22.48 | $184K | SEC |
Who owns AMPH? Hedge funds and superinvestors
4 13F filers hold AMPH among their 50 largest positions, worth $22.1M combined. The biggest bets by portfolio weight are Bridge City Capital, LLC (2.1%), Lam Group, Inc. (1.7%) and Denali Advisors LLC (0.8%). In their latest 13Fs, 0 managers opened a new position and 1 added to one.
| Manager | % of portfolio | Value | Shares | Last quarter | 13F |
|---|---|---|---|---|---|
| Bridge City Capital, LLCInstitutional asset manager | 2.1% | $9.9M | 383,901 | +13.3% shares | Q3 2026 |
| Denali Advisors LLCInstitutional asset manager | 0.8% | $7.6M | 375,965 | — | Q2 2026 |
| Lam Group, Inc.Wealth manager | 1.7% | $3.4M | 130,800 | +0.0% shares | Q3 2026 |
| SummerHaven Investment Management, LLCAsset manager | 0.7% | $1.3M | 48,852 | — | Q3 2026 |
Each manager counts with its latest 13F (Q3 2026: 3, Q2 2026: 1). Screen AMPH in the grand portfolio →
AMPH stock trades by members of Congress
No member of Congress has disclosed a trade in AMPH.
AMPH questions and answers
Are insiders buying AMPH stock?
Between Aug 1, 2026 and Oct 29, 2026, 3 AMPH insiders filed 5 sales worth $764K on SEC Form 4, and no open-market purchases; 2 of the sales were pre-planned under Rule 10b5-1.
Which hedge funds own AMPH?
4 13F filers hold AMPH among their 50 largest positions, worth $22.1M combined. The biggest bets by portfolio weight are Bridge City Capital, LLC (2.1%), Lam Group, Inc. (1.7%) and Denali Advisors LLC (0.8%). In their latest 13Fs, 0 managers opened a new position and 1 added to one.
Has Congress traded AMPH?
No member of Congress has disclosed a trade in AMPH.
Who is the largest holder of AMPH?
Among 13F filers, Bridge City Capital, LLC reports the largest AMPH position, $9.9M (383,901 shares) in its Q3 2026 13F. The biggest bet by portfolio weight is Bridge City Capital, LLC's: 2.1% of its portfolio.
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