Public ownership evidence

Amphastar Pharmaceuticals, Inc. (AMPH) Ownership Disclosures

Read AMPH insider transactions, institutional 13F filings and Congressional disclosures with report dates, public availability and original receipts.

As of 2026-10-10T12:08:28.848Z

Separate the three disclosure sources

Step 1 of 3

Recent Form 4 activity

Amphastar Pharmaceuticals, Inc.: source evidence dated 2026-10-10T12:08:28.848Z.

Available
2026-09-23
Trade date
2026-09-21
Reporting owners
PETERS WILLIAM J
Code
S
Shares
4,139
Reported value
Not reported
What you should see

The displayed owner or issuer and source fields identify the receipt to verify; keep reporting and availability dates separate.

Step 2 of 3

Is this an insider transaction, 13F holding, or Congressional event?

Each source has different dates and units. Raw ticker-matched receipts, including amendments, are not deduplicated current ownership totals.

SEC 0001263136-26-000014
What you should see

Follow the source receipt or manager/member profile. Avoid combining transaction value and 13F position value into an ownership percentage.

Step 3 of 3

Read AMPH fundamentals

Follow the source receipt or manager/member profile. Avoid combining transaction value and 13F position value into an ownership percentage.

Read AMPH fundamentals
What you should see

Keep reporting dates and units beside the answer, and inspect its original citations.

Recent Form 4 activity

See the complete recent form 4 activity

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2026-09-232026-09-21PETERS WILLIAM JS4,139Not reported
2026-09-172026-09-16Zhou RongS10,000Not reported
2026-09-042026-09-02Zhou RongS3,187Not reported
2026-08-132026-08-11PRINS RICHARD KS7,973Not reported
2026-08-122026-08-07PETERS WILLIAM JS8,180Not reported
2026-07-142026-07-09Pierce Anthony TA7,886Not reported
2026-07-142026-07-09Pierce Anthony TA16,646Not reported

90-day public availability window, up to 50 records.

Recent institutional filing receipts

These are raw ticker-matched positions in recent 13F receipts, including amendments. They are not deduplicated current ownership totals. Open the manager profile to inspect its effective filing book.

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Advisors Asset Management, Inc.2024-03-312026-08-27930$40,836None
Advisors Asset Management, Inc.2023-09-302026-08-27442$20,328None
Advisors Asset Management, Inc.2023-12-312026-08-27843$52,140None
CALIFORNIA STATE TEACHERS RETIREMENT SYSTEM2026-06-302026-08-2536,151$729,527None
CALIFORNIA STATE TEACHERS RETIREMENT SYSTEM2026-06-302026-08-25729,527$36,151,000None
Advisors Asset Management, Inc.2024-09-302026-08-22873$42,367None
Advisors Asset Management, Inc.2024-06-302026-08-22926$37,040None
Advisors Asset Management, Inc.2024-12-312026-08-22399$14,815None
Assenagon Asset Management S.A.2026-06-302026-08-2215,216$307,059None
Fulcrum Asset Management LLP2026-06-302026-08-191,750$36,243None
Empowered Funds, LLC2026-06-302026-08-18162,812$3,285,546None
PUBLIC EMPLOYEES RETIREMENT SYSTEM OF OHIO2026-06-302026-08-18754$15,216None
Aster Capital Management (DIFC) Ltd2026-06-302026-08-15238$4,803None
JPL Wealth Management, LLC2026-06-302026-08-155$101None
Basecamp Wealth Advisors LLC2026-06-302026-08-154,416$89,115None
XTX Topco Ltd2026-06-302026-08-1546,808$944,585None
CHARLES SCHWAB INVESTMENT MANAGEMENT INC2026-06-302026-08-15310,178$6,259,392None
Sixth Street Partners Management Company, L.P.2026-06-302026-08-15310,178$6,259,392None
OSAIC HOLDINGS, INC.2026-06-302026-08-1512,742$257,132None
Squarepoint Ops LLC2026-06-302026-08-1578,795$1,590,083None
Man Group plc2026-06-302026-08-1517,342$349,962None
MetLife Investment Management, LLC2026-06-302026-08-1520,761$418,957None
Engineers Gate Manager LP2026-06-302026-08-1530,191$609,254None
JANE STREET GROUP, LLC2026-06-302026-08-1590,524$1,826,774None
JANE STREET GROUP, LLC2026-06-302026-08-1588,210$1,780,078None
State of Tennessee, Department of Treasury2026-06-302026-08-158,619$173,932None
VOLORIDGE INVESTMENT MANAGEMENT, LLC2026-06-302026-08-1550,912$1,027,404None
Legal & General Group Plc2026-06-302026-08-1520,799$419,725None
Legal & General Group Plc2026-06-302026-08-155,600$113,008None
Legal & General Group Plc2026-06-302026-08-1551,882$1,046,979None
HRT FINANCIAL LP2026-06-302026-08-15387,530$7,820,000None
SUSQUEHANNA INTERNATIONAL GROUP, LLP2026-06-302026-08-1511,200$226,016Call
SUSQUEHANNA INTERNATIONAL GROUP, LLP2026-06-302026-08-1550,565$1,020,402None
Gotham Asset Management, LLC2026-06-302026-08-1510,139$204,605None
SYSTEMATIC FINANCIAL MANAGEMENT LP2026-06-302026-08-1521,124$426,312None
SYSTEMATIC FINANCIAL MANAGEMENT LP2026-06-302026-08-15416,260$8,400,127None
MILLENNIUM MANAGEMENT LLC2026-06-302026-08-1531,814$642,007None
Thrivent Financial for Lutherans2026-06-302026-08-1522,295$450,000None
JONES FINANCIAL COMPANIES LLLP2026-06-302026-08-15228$4,966None
AMERIPRISE FINANCIAL INC2026-06-302026-08-15759$15,317None
AMERIPRISE FINANCIAL INC2026-06-302026-08-1567,485$1,361,848None
AQR CAPITAL MANAGEMENT LLC2026-06-302026-08-15206,841$4,174,051None
AQR CAPITAL MANAGEMENT LLC2026-06-302026-08-15357$7,204None
AQR CAPITAL MANAGEMENT LLC2026-06-302026-08-157$141None
AQR CAPITAL MANAGEMENT LLC2026-06-302026-08-1529$585None
AQR CAPITAL MANAGEMENT LLC2026-06-302026-08-15145$2,926None
AQR CAPITAL MANAGEMENT LLC2026-06-302026-08-151,272$25,669None
MANUFACTURERS LIFE INSURANCE COMPANY, THE2026-06-302026-08-1514,247$287,504None
ROYAL BANK OF CANADA2026-06-302026-08-153,654$74,000None
ROYAL BANK OF CANADA2026-06-302026-08-1575$2,000None

90-day public filing window, up to 50 source positions.

Advisors Asset Management, Inc. ↗Advisors Asset Management, Inc. ↗Advisors Asset Management, Inc. ↗CALIFORNIA STATE TEACHERS RETIREMENT SYSTEM ↗CALIFORNIA STATE TEACHERS RETIREMENT SYSTEM ↗Advisors Asset Management, Inc. ↗Advisors Asset Management, Inc. ↗Advisors Asset Management, Inc. ↗Assenagon Asset Management S.A. ↗Fulcrum Asset Management LLP ↗

Recent Congressional disclosures

No matching Congressional transactions were returned in this source preview.

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No records are available for this view.

Bounded public source preview, up to 25 disclosed events.

How to read the disclosure dates

The tables report different things: insider transactions, institutional positions and Congressional transaction ranges. Read each table with its source dates and units. They cannot be added into a combined ownership percentage.

  1. Company insiders

    SEC Form 4 purchases, sales and awards report transactions and their public filing availability.

  2. Institutional managers

    13F reports disclose delayed quarter-end positions. They are not a record of trades between quarters.

  3. Congressional filers

    Periodic transaction reports disclose transaction dates and amount brackets. Public filing dates determine what researchers could know.

Institutional source directory ↗Congressional source directory ↗

Read the transaction codes

Awards use transaction code A, purchases P and sales S. An acquisition from an award is not the same as an open-market purchase. Joint filers may share a transaction. Use original receipts and availability dates to interpret the events.

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