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Amphastar Pharmaceuticals, Inc.

AMPH
Exchange
Nasdaq
Industry
Pharmaceutical Preparations
SEC CIK
0001297184

In the last 90 days, Amphastar Pharmaceuticals, Inc. insiders filed 0 open-market purchases and 5 sales; 212 institutions reported holding it in 13F filings for Q2 2026, worth $572.4M in total; no superinvestor holds it.

Open-market trades, last 90 days

Open-market purchases (P) and sales (S) by Amphastar Pharmaceuticals, Inc. insiders, counted by Form 4 filing. Trades with a flagged price and duplicate filings are left out.

Open-market buys
0 filings
Open-market sells
5 filings
3 insiders, $763.9K in total
Insiders trading
3
Net value
−$763.9K
Purchases minus sales

Insider roster

Directors, officers and 10% owners who have filed a Form 4 for Amphastar Pharmaceuticals, Inc., current and former, most recent filer first. Last reported holding is the position after the last non-derivative trade in their latest filing.

Insider roster for Amphastar Pharmaceuticals, Inc.
NameTitleLast reported holdingLast filingFilings, past year
Peters William JCFO, EVP & TREASURER168,707Sep 23, 20266
Zhou RongSENIOR EVP, PRODUCTION CENTER169,203Sep 17, 20267
Prins Richard KDirector29,625Aug 12, 20263
Pierce Anthony TDirector7,886Jul 13, 20261
Zasloff Michael ADirector37,667Jun 3, 20261
Lee HowardDirector159,350Jun 3, 20261
Gerst Diane G.Director31,899Jun 3, 20261
Deflin GayleDirector19,057Jun 3, 20261
Gaugh David RussellDirector14,447Jun 3, 20261
Luo Mary Z.COO, Chief Scientist, Chairman1,245,125IndirectMar 17, 20264
Zhang Jack Y.CEO & CHIEF SCIENTIFIC OFFICER1,245,125IndirectMar 17, 20264
Liawatidewi YakobEVP CORP ADMIN CENTER121,892Mar 17, 20264
Petersen Floyd F.Director71,368Dec 15, 20254

Insider trades

Each row adds up one type of transaction in one Form 4 filing. Only open-market purchases (P) and sales (S) are shown by default; use the filters to see grants, option exercises and other codes.

Insider trades
Filed (ET)Trade dateFiling delayInsiderTransactionSharesAvg priceValueHolding changeFlags
Sep 23, 2026 (view filing)6:02 PM ETSep 212 daysPeters William JCFO, EVP & TREASURERSSale−4.14K$25.00−$103.5K−2.4%168.7K after10b5-1
Sep 17, 2026 (view filing)6:19 PM ETSep 161 dayZhou RongSENIOR EVP, PRODUCTION CENTERSSale−10.0K$23.94−$239.4K−5.6%169.2K after
Sep 3, 2026 (view filing)7:42 PM ETSep 21 dayZhou RongSENIOR EVP, PRODUCTION CENTERSSale−3.19K$23.63−$75.3K−1.8%169.2K after
Aug 12, 2026 (view filing)6:14 PM ETAug 111 dayPrins Richard KDirectorSSale−7.97K$20.30−$161.9K−21.2%29.6K after
Aug 11, 2026 (view filing)4:57 PM ETAug 74 daysPeters William JCFO, EVP & TREASURERSSale−8.18K$22.48−$183.9K−4.5%172.8K after10b5-1
Dec 18, 2025 (view filing)Dec 171 dayZhou RongSENIOR EVP, PRODUCTION CENTERSSale−9.79K$26.20−$256.4K−6.6%138.0K after
Dec 15, 2025 (view filing)Dec 11-124 daysPetersen Floyd F.DirectorSSale−4.16K$25.82−$107.5K−5.5%71.4K after2 lots
Nov 25, 2025 (view filing)Nov 25Same dayPrins Richard KDirectorSSale−4.18K$27.10−$113.3K−10.6%35.2K after
Nov 17, 2025 (view filing)Nov 134 daysPetersen Floyd F.DirectorSSale−16.7K$26.49−$441.8K−18.1%75.5K after
Nov 5, 2025 (view filing)Nov 32 daysPetersen Floyd F.DirectorSSale−500$25.27−$12.6K−0.7%75.5K after10b5-1
Oct 2, 2025 (view filing)Oct 11 dayPetersen Floyd F.DirectorSSale−500$27.20−$13.6K−0.7%76.0K after10b5-1
Sep 3, 2025 (view filing)Sep 21 dayPetersen Floyd F.DirectorSSale−500$30.98−$15.5K−0.6%76.5K after10b5-1
Aug 4, 2025 (view filing)Aug 13 daysPetersen Floyd F.DirectorSSale−500$20.83−$10.4K−0.6%77.0K after10b5-1
Jul 3, 2025 (view filing)Jul 21 dayPetersen Floyd F.DirectorSSale−500$23.47−$11.7K−0.6%77.5K after10b5-1
Jun 4, 2025 (view filing)Jun 22 daysPetersen Floyd F.DirectorSSale−500$25.67−$12.8K−0.7%72.9K after10b5-1
May 2, 2025 (view filing)May 11 dayPetersen Floyd F.DirectorSSale−500$24.08−$12.0K−0.7%73.4K after10b5-1
Apr 2, 2025 (view filing)Apr 11 dayPetersen Floyd F.DirectorSSale−500$28.38−$14.2K−0.7%73.9K after10b5-1
Mar 7, 2025 (view filing)Mar 61 dayPetersen Floyd F.DirectorSSale−1.00K$27.99−$28.0K−1.3%74.4K after10b5-1
Mar 6, 2025 (view filing)Mar 42 daysPeters William JCFO, EVP & TREASURERSSale−4.23K$27.54−$116.5K−4.2%97.4K after10b5-1
Dec 16, 2024 (view filing)Dec 12-134 daysZhou RongSENIOR EVP, PRODUCTION CENTERSSale−15.0K$44.86−$672.9K−11.2%118.5K after2 lots
Dec 11, 2024 (view filing)Dec 92 daysPrins Richard KDirectorSSale−10.0K$43.77−$437.7K−24.7%30.5K after
Nov 13, 2024 (view filing)Nov 121 dayZhou RongSENIOR EVP, PRODUCTION CENTERSSale−6.89K$48.88−$336.9K−5.5%118.4K after
Nov 13, 2024 (view filing)Nov 121 dayPrins Richard KDirectorSSale−5.00K$48.80−$244.0K−13.7%31.5K after
Nov 8, 2024 (view filing)Nov 62 daysLiawatidewi YakobEVP CORP ADMIN CENTERSSale−5.21K$52.05−$271.4K−6.5%74.9K after10b5-1
Nov 8, 2024 (view filing)Nov 62 daysPeters William JCFO, EVP & TREASURERSSale−7.43K$52.05−$386.5K−7.3%94.1K after10b5-1
Sep 17, 2024 (view filing)Sep 134 daysZhou RongSENIOR EVP, PRODUCTION CENTERSSaleCommon Srock−3.00K$48.26−$144.8K−2.5%118.4K after
Sep 6, 2024 (view filing)Sep 51 dayPetersen Floyd F.DirectorSSale−3.00K$46.47−$139.4K−3.8%75.4K after
Aug 27, 2024 (view filing)Aug 261 dayZhou RongSENIOR EVP, PRODUCTION CENTERSSaleCommon Srock−4.00K$48.35−$193.4K−3.3%118.4K after
Aug 13, 2024 (view filing)Aug 121 dayPrins Richard KDirectorSSale−17.1K$43.07−$736.5K−33.5%34.0K after
Aug 2, 2024 (view filing)Jul 312 daysPeters William JCFO, EVP & TREASURERSSale−10.3K$44.23−$454.8K−9.9%94.1K after10b5-1
Jun 28, 2024 (view filing)Jun 271 dayPeters William JCFO, EVP & TREASURERSSale−3.60K$40.93−$147.2K−3.7%94.1K after2 lots10b5-1
Jun 11, 2024 (view filing)Jun 101 dayPetersen Floyd F.DirectorSSale−3.00K$41.40−$124.2K−3.7%78.4K after
Jun 5, 2024 (view filing)Jun 32 daysPetersen Floyd F.DirectorSSale−500$42.65−$21.3K−0.6%78.3K after10b5-1
May 2, 2024 (view filing)May 11 dayPetersen Floyd F.DirectorSSale−500$41.67−$20.8K−0.6%78.8K after10b5-1
Apr 2, 2024 (view filing)Apr 11 dayPetersen Floyd F.DirectorSSale−500$43.43−$21.7K−0.6%79.3K after10b5-1
Mar 8, 2024 (view filing)Mar 62 daysPeters William JCFO, EVP & TREASURERSSale−18.1K$46.48−$843.0K−14.0%111.5K after3 lots10b5-1
Mar 6, 2024 (view filing)Mar 51 dayZasloff Michael ADirectorSSale−12.5K$47.18−$589.7K−37.0%21.3K after2 lots
Mar 4, 2024 (view filing)Mar 13 daysPetersen Floyd F.DirectorSSale−500$45.69−$22.8K−0.6%79.8K after2 lots10b5-1
Feb 2, 2024 (view filing)Feb 11 dayPetersen Floyd F.DirectorSSale−500$53.10−$26.5K−0.6%80.3K after2 lots10b5-1
Jan 11, 2024 (view filing)4:37 PM ETJan 101 dayLuo Mary Z. and 1 otherCOO,Chief Scientist & ChairmanSSale−131.4K$54.59−$7.17M−10.6%1.10M after4 lots10b5-1
Jan 10, 2024 (view filing)6:27 PM ETJan 8-92 daysLuo Mary Z. and 1 otherCOO,Chief Scientist & ChairmanSSale−219.8K$58.23−$12.8M−15.1%1.24M after10 lots10b5-1
Jan 3, 2024 (view filing)Jan 21 dayPetersen Floyd F.DirectorSSale−500$61.36−$30.7K−0.6%80.8K after2 lots10b5-1
Dec 5, 2023 (view filing)Dec 1-44 daysZhou RongSenior EVP, Production CenterSSale−7.83K$59.03−$462.2K−6.5%112.4K after2 lots
Dec 4, 2023 (view filing)Dec 13 daysPetersen Floyd F.DirectorSSale−500$57.90−$29.0K−0.6%81.3K after2 lots10b5-1
Nov 20, 2023 (view filing)Nov 173 daysPrins Richard KDirectorSSale−4.00K$55.86−$223.4K−11.1%31.9K after
Nov 16, 2023 (view filing)Nov 142 daysPeters William JCFO, EVP & TreasurerSSale−59.3K$55.67−$3.30M−36.9%101.4K after3 lots10b5-1
Nov 15, 2023 (view filing)Nov 132 daysPrins Richard KDirectorSSale−5.00K$52.50−$262.5K−12.2%35.9K after
Nov 15, 2023 (view filing)Nov 141 dayDeflin GayleDirectorSSale−4.16K$55.45−$230.8K−60.5%2.72K after
Nov 2, 2023 (view filing)Nov 11 dayPetersen Floyd F.DirectorSSale−500$45.30−$22.6K−0.6%81.8K after10b5-1
Oct 3, 2023 (view filing)Oct 21 dayPetersen Floyd F.DirectorSSale−500$45.78−$22.9K−0.6%82.3K after10b5-1