Amphastar Pharmaceuticals Inc. (AMPH) Insider Trading

Last 12 months

Insiders sold $1.7M and bought nothing on the open market.

18% of the selling was scheduled in advance under 10b5-1 plans. Director Floyd F. Petersen sold $442k on Nov 13, 2025, 18% of their stake, outside a plan. The last open-market buy by an executive or director was in Aug 2020.

Net open-market

−$1.7M

0 buys · 10 sales

Under a 10b5-1 plan

18%

of the value sold

Insiders who bought / sold

0 / 4

executives and directors

Last open-market buy

Aug 2020

Aug 14, 2020

Get an email when AMPH's executives or directors buy, or make a large sale outside a plan.

Trades · last 2 years

Date	Insider	Trade	Shares	Price	Value	Of their stake	Filing
Sep 21	William J Peters CFO, EVP & TREASURER	Sold10b5-1 plan	4,139	$25.00	$103k	2.4%	Form 4
Sep 16	Rong Zhou SENIOR EVP, PRODUCTION CENTER	SoldNo plan	10,000	$23.94	$239k	5.4%	Form 4
Sep 2	Rong Zhou SENIOR EVP, PRODUCTION CENTER	SoldNo plan	3,187	$23.63	$75k	1.2%	Form 4
Aug 11	Richard K Prins Director	SoldNo plan	7,973	$20.30	$162k	21%	Form 4
Aug 7	William J Peters CFO, EVP & TREASURER	Sold10b5-1 plan	8,180	$22.48	$184k	4.5%	Form 4
Dec 17, 2025	Rong Zhou SENIOR EVP, PRODUCTION CENTER	SoldNo plan	9,787	$26.20	$256k	6.4%	Form 4
Dec 11, 2025 – Dec 12, 2025	Floyd F. Petersen Director	SoldNo plan 2 parts	4,163	$25.82 average	$108k	5.5%	Form 4
Nov 25, 2025	Richard K Prins Director	SoldNo plan	4,179	$27.10	$113k	11%	Form 4
Nov 13, 2025	Floyd F. Petersen Director	SoldNo plan	16,679	$26.49	$442k	18%	Form 4
Nov 3, 2025	Floyd F. Petersen Director	Sold10b5-1 plan	500	$25.27	$13k	0.7%	Form 4
Oct 1, 2025	Floyd F. Petersen Director	Sold10b5-1 plan	500	$27.20	$14k	0.7%	Form 4
Sep 2, 2025	Floyd F. Petersen Director	Sold10b5-1 plan	500	$30.98	$15k	0.6%	Form 4
Aug 1, 2025	Floyd F. Petersen Director	Sold10b5-1 plan	500	$20.83	$10k	0.6%	Form 4
Jul 2, 2025	Floyd F. Petersen Director	Sold10b5-1 plan	500	$23.47	$12k	0.6%	Form 4
Jun 2, 2025	Floyd F. Petersen Director	Sold10b5-1 plan	500	$25.67	$13k	0.6%	Form 4
May 1, 2025	Floyd F. Petersen Director	Sold10b5-1 plan	500	$24.08	$12k	0.7%	Form 4
Apr 1, 2025	Floyd F. Petersen Director	Sold10b5-1 plan	500	$28.38	$14k	0.7%	Form 4
Mar 6, 2025	Floyd F. Petersen Director	Sold10b5-1 plan	1,000	$27.99	$28k	1.3%	Form 4
Mar 4, 2025	William J Peters CFO, EVP & TREASURER	Sold10b5-1 plan	4,231	$27.54	$117k	4.2%	Form 4
Dec 12, 2024 – Dec 13, 2024	Rong Zhou SENIOR EVP, PRODUCTION CENTER	SoldNo plan 2 parts	15,000	$44.86 average	$673k	11%	Form 4
Dec 9, 2024	Richard K Prins Director	SoldNo plan	10,000	$43.77	$438k	25%	Form 4
Nov 12, 2024	Rong Zhou SENIOR EVP, PRODUCTION CENTER	SoldNo plan	6,893	$48.88	$337k	3.1%	Form 4
Nov 12, 2024	Richard K Prins Director	SoldNo plan	5,000	$48.80	$244k	14%	Form 4
Nov 6, 2024	Yakob Liawatidewi EVP CORP ADMIN CENTER	Sold10b5-1 plan	5,214	$52.05	$271k	6.3%	Form 4
Nov 6, 2024	William J Peters CFO, EVP & TREASURER	Sold10b5-1 plan	7,426	$52.05	$387k	7.3%	Form 4

Sep 2110b5-1 plan
William J Peters
CFO, EVP & TREASURER · sold 4,139 at $25.00
$103k
2.4% of stake
Sep 16No plan
Rong Zhou
SENIOR EVP, PRODUCTION CENTER · sold 10,000 at $23.94
$239k
5.4% of stake
Sep 2No plan
Rong Zhou
SENIOR EVP, PRODUCTION CENTER · sold 3,187 at $23.63
$75k
1.2% of stake
Aug 11No plan
Richard K Prins
Director · sold 7,973 at $20.30
$162k
21% of stake
Aug 710b5-1 plan
William J Peters
CFO, EVP & TREASURER · sold 8,180 at $22.48
$184k
4.5% of stake
Dec 17, 2025No plan
Rong Zhou
SENIOR EVP, PRODUCTION CENTER · sold 9,787 at $26.20
$256k
6.4% of stake
Dec 11, 2025 – Dec 12, 2025No plan
Floyd F. Petersen
Director · sold 4,163 at avg $25.82
$108k
5.5% of stake
Nov 25, 2025No plan
Richard K Prins
Director · sold 4,179 at $27.10
$113k
11% of stake
Nov 13, 2025No plan
Floyd F. Petersen
Director · sold 16,679 at $26.49
$442k
18% of stake
Nov 3, 202510b5-1 plan
Floyd F. Petersen
Director · sold 500 at $25.27
$13k
0.7% of stake
Oct 1, 202510b5-1 plan
Floyd F. Petersen
Director · sold 500 at $27.20
$14k
0.7% of stake
Sep 2, 202510b5-1 plan
Floyd F. Petersen
Director · sold 500 at $30.98
$15k
0.6% of stake
Aug 1, 202510b5-1 plan
Floyd F. Petersen
Director · sold 500 at $20.83
$10k
0.6% of stake
Jul 2, 202510b5-1 plan
Floyd F. Petersen
Director · sold 500 at $23.47
$12k
0.6% of stake
Jun 2, 202510b5-1 plan
Floyd F. Petersen
Director · sold 500 at $25.67
$13k
0.6% of stake
May 1, 202510b5-1 plan
Floyd F. Petersen
Director · sold 500 at $24.08
$12k
0.7% of stake
Apr 1, 202510b5-1 plan
Floyd F. Petersen
Director · sold 500 at $28.38
$14k
0.7% of stake
Mar 6, 202510b5-1 plan
Floyd F. Petersen
Director · sold 1,000 at $27.99
$28k
1.3% of stake
Mar 4, 202510b5-1 plan
William J Peters
CFO, EVP & TREASURER · sold 4,231 at $27.54
$117k
4.2% of stake
Dec 12, 2024 – Dec 13, 2024No plan
Rong Zhou
SENIOR EVP, PRODUCTION CENTER · sold 15,000 at avg $44.86
$673k
11% of stake
Dec 9, 2024No plan
Richard K Prins
Director · sold 10,000 at $43.77
$438k
25% of stake
Nov 12, 2024No plan
Rong Zhou
SENIOR EVP, PRODUCTION CENTER · sold 6,893 at $48.88
$337k
3.1% of stake
Nov 12, 2024No plan
Richard K Prins
Director · sold 5,000 at $48.80
$244k
14% of stake
Nov 6, 202410b5-1 plan
Yakob Liawatidewi
EVP CORP ADMIN CENTER · sold 5,214 at $52.05
$271k
6.3% of stake
Nov 6, 202410b5-1 plan
William J Peters
CFO, EVP & TREASURER · sold 7,426 at $52.05
$387k
7.3% of stake

How to read this. Insiders sell for many reasons: taxes, diversifying, a house. Open-market buys are rarer and say more. A 10b5-1 plan is a trading schedule set up months in advance, so those sales were not timed on news. Large holders (funds and 10% owners) are listed under Everything but not counted as insiders. If you own or watch AMPH, we send a push when an executive buys or makes a large sale outside a plan.

Source: SEC Form 4 filings, filed within two business days of each trade and checked for new ones every hour.

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Spot a number that looks wrong? Check it in AMPH's SEC filings or

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Data sourced from SEC EDGAR filings and third-party price providers. Scores, valuations, and metrics are algorithmic estimates. This is not investment advice. See our Terms and Methodology.

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