Reporting owner · CIK 0001263136
Peters William J
Visual SEC Form 4 history across 1 companies, 2 transactions and 2 filings.
CFO, EVP, TRESCFO, EVP & TREASURERAmphastar Pharmaceuticals, Inc.
Open-market mix
0%buys
Open-market buy performance
90-day forward return on this insider's open-market purchases
Forward return is not available yet
We compute this from each buy's stock performance 90 days after the transaction. The price history is still being populated for this insider's their open-market buys, so the average and median will appear here once the daily price refresh has covered the relevant trading days.
Disclosed ownership
How reported shareholdings evolved
Non-derivative shares held after reported transactions—not stock prices or a complete portfolio.
2 observations · Mar 6, 2025 – Sep 21, 2026. Window ends at the latest available report, not today.
Selected observation · Sep 21, 2026168,707 shares reported
Inspect transaction View exact observations and source transactions
| Transaction date | Shares held after | Filed | Source |
|---|---|---|---|
| Mar 6, 2025 | 93,483 | Mar 10, 2025 | View transaction |
| Sep 21, 2026 | 168,707 | Sep 23, 2026 | View transaction |
Securities and direct/indirect ownership contexts are kept separate and never summed. Joint filings may associate the same disclosed row with multiple owners. Unknown values are omitted, not treated as zero. Lines connect observations for readability; they do not establish holdings between filings, cost basis, or current ownership. Amendments and stock splits require reviewing the source.
Monthly open-market activity
Reported purchase and sale transaction counts
Buys Sells
Net value flow
Buys minus sells
Mar 25
$0
Sep 26
−$103.5K
Transaction texture
Ownership and ticket size
Average P/S size$103.5K
Median P/S size$103.5K
Direct2
Indirect0
Sep 21, 2026sale
Filing-only signals
Deterministic matches in this insider's history
Latest Form 4 facts
Quick context from source filings
Latest transaction
sale at Amphastar Pharmaceuticals, Inc. on Sep 21, 2026 valued at $103,475.
Review SEC filingLatest buy
No open-market insider purchase is available.
Latest sale
sale at Amphastar Pharmaceuticals, Inc. on Sep 21, 2026 valued at $103,475.
Review SEC filingAssociated companies
Visual map of known reporting history
Latest insider transactions
Form 4 filings from available history. Click any column to sort; click it again to flip the order.
| ID | Ticker | Insider | Role | Type | Shares | Value | Code | Filed | Trans date |
|---|---|---|---|---|---|---|---|---|---|
| #228568 | AMPH | Peters William J | CFOEVPTRES | sale10b5-1 | 4.13k | -$10.3M | S | 09/23 | 09/21 |
| #200019 | AMPH | Peters William J | CFOEVPTRES | withholding | 2.14k | -$6.06M | F | 03/10/2025 | 03/06/2025 |
Peters William J Insider Activity FAQ
SEC Form 4 context
Who is Peters William J?
Peters William J is a reporting owner in SEC Form 4 filings with reporting owner CIK 0001263136.
Which companies has Peters William J reported transactions for?
Amphastar Pharmaceuticals, Inc.
When was Peters William J's latest insider buy?
No open-market insider purchase is available for this period.
When was Peters William J's latest insider sale?
sale at Amphastar Pharmaceuticals, Inc. on Sep 21, 2026 valued at $103,475.
Where can I see the original SEC filings?
Each transaction row links directly to the source SEC filing so the reported Form 4 details can be reviewed.
Are performance metrics included?
This version does not calculate win rates, forward returns, benchmark-adjusted returns, or high-conviction scores.