221 tracked 13F filers disclose a position in AMPX as of the latest SEC 13F filings, a combined $1.2B in reported value. Holders and values reflect the 13F filers Arkolith currently tracks, not the entire institutional universe. Counts and totals are a floor, not the full institutional ownership.
| # | Fund | Position value | Shares | Last move | As of | History |
|---|---|---|---|---|---|---|
| 1 | BlackRock, Inc. | $155.5M | 9.2M | ▲+4.5% Added · +402K sh | Q1 2026 | |
| 2 | VANGUARD CAPITAL MANAGEMENT LLC | $82.8M | 4.9M | →First observed position No prior filed position | Q1 2026 | |
| 3 | JANE STREET GROUP, LLC | $70.1M | 4.2M | ▲19× Added · +3.9M sh | Q1 2026 | |
| 4 | GEODE CAPITAL MANAGEMENT, LLC | $48.8M | 3.5M | ▲+25% Added · +706K sh | Q2 2026 | |
| 5 | TWO SIGMA INVESTMENTS, LP | $59.1M | 3.5M | ▲+144% Added · +2.1M sh | Q1 2026 | |
| 6 | STATE STREET CORP | $44.9M | 3.2M | ▲+19% Added · +528K sh | Q2 2026 | |
| 7 | MORGAN STANLEY | $53.3M | 3.2M | ▲+13% Added · +352K sh | Q1 2026 | |
| 8 | UBS Group AG | $39.0M | 2.3M | ▲+10% Added · +213K sh | Q1 2026 | |
| 9 | GOLDMAN SACHS GROUP INC | $37.5M | 2.2M | ▲+1.4% Added · +31K sh | Q1 2026 | |
| 10 | MASSACHUSETTS FINANCIAL SERVICES CO /MA/ | $34.1M | 2.0M | ▲New +2.0M sh | Q1 2026 | |
| 11 | PRICE T ROWE ASSOCIATES INC /MD/ | $32.0M | 1.9M | ▲24× Added · +1.8M sh | Q1 2026 | |
| 12 | Baird Financial Group, Inc. | $26.7M | 1.6M | ▲+105% Added · +812K sh | Q1 2026 | |
| 13 | CITADEL ADVISORS LLC | $24.3M | 1.4M | ▲+216% Added · +984K sh | Q1 2026 | |
| 14 | Hood River Capital Management LLC | $19.6M | 1.4M | ▲+49% Added · +463K sh | Q2 2026 | |
| 15 | NORGES BANK | $10.3M | 1.3M | ▲New +1.3M sh | Q4 2025 | |
| 16 | MARSHALL WACE, LLP | $20.7M | 1.2M | ▲New +1.2M sh | Q1 2026 | |
| 17 | Qube Research & Technologies Ltd | $20.7M | 1.2M | ▲+40% Added · +353K sh | Q1 2026 | |
| 18 | JPMORGAN CHASE & CO | $17.9M | 1.2M | ▲15× Added · +1.1M sh | Q1 2026 | |
| 19 | D. E. Shaw & Co., Inc. | $18.1M | 1.1M | ▲New +1.1M sh | Q1 2026 | |
| 20 | VANGUARD PORTFOLIO MANAGEMENT LLC | $18.1M | 1.1M | →First observed position No prior filed position | Q1 2026 | |
| 21 | BARCLAYS PLC | $17.8M | 1.1M | ▲+124% Added · +585K sh | Q1 2026 | |
| 22 | CHARLES SCHWAB INVESTMENT MANAGEMENT INC | $17.5M | 1.0M | ▲+0.2% Added · +3K sh | Q1 2026 | |
| 23 | MILLENNIUM MANAGEMENT LLC | $17.5M | 1.0M | ▼−4.6% Reduced · −50K sh | Q1 2026 | |
| 24 | Nearwater Capital Markets, Ltd | $14.3M | 1.0M | ▲New +1.0M sh | Q2 2026 | |
| 25 | NORTHERN TRUST CORP | $17.2M | 1.0M | ▲+6.2% Added · +59K sh | Q1 2026 |
Holders and values reflect the 13F filers Arkolith currently tracks, not the entire institutional universe. Counts and totals are a floor, not the full institutional ownership.
Last quarter, 13 funds opened a new position in AMPX and 26 added to an existing one, while 14 reduced and 0 exited entirely — based on 13F filings from active, signal-eligible managers (passive index funds and other mechanical holders are excluded from this count).
| Company | Co-held by | Combined value |
|---|---|---|
| MICROSOFT CORPMSFT | 111 funds | $208.4B |
| NVIDIA CORPNVDA | 109 funds | $296.1B |
| APPLE INCAAPL | 109 funds | $221.3B |
| AMAZON.COM INCAMZN | 109 funds | $150.8B |
| ALPHABET INC-CL AGOOGL | 108 funds | $117.7B |
| META PLATFORMS INC-CLASS AMETA | 108 funds | $82.6B |
| MICRON TECHNOLOGY INCMU | 108 funds | $27.6B |
| ALPHABET INC-CL CGOOG | 106 funds | $94.2B |
| ADVANCED MICRO DEVICESAMD | 106 funds | $26.0B |
| ELI LILLY & COLLY | 105 funds | $57.7B |
| TESLA INCTSLA | 105 funds | $53.0B |
| VISA INC-CLASS A SHARESV | 105 funds | $45.5B |
Ranked by how many of AMPX's institutional holders also hold each name, a cross-fund conviction signal.
| Date | Insider | Role | Action | Shares | Value |
|---|---|---|---|---|---|
| Aug 24, 2026 | Stepien Thomas M | Chief Executive Officer, Director | Sell (S) | 8K | $80K |
| Aug 21, 2026 | Stepien Thomas M | Chief Executive Officer, Director | Sell (S) | 24K | $243K |
| Aug 21, 2026 | Sun Kang | Director | Sell (S) | 62K | $642K |
| Aug 21, 2026 | Stefan Constantin Ionel | Chief Technology Officer | Sell (S) | 30K | $307K |
| Jun 15, 2026 | DIXON DONALD R | Director | Sell (S) | 85K | $1.5M |
| Jun 9, 2026 | DIXON DONALD R | Director | Sell (S) | 40K | $765K |
| Jun 4, 2026 | Stepien Thomas M | Chief Executive Officer, Director | Sell (S) | 2K | $42K |
| May 27, 2026 | Stefan Constantin Ionel | Chief Technology Officer | Sell (S) | 3K | $55K |
| May 27, 2026 | Sun Kang | Director | Sell (S) | 356 | $6K |
| May 27, 2026 | Stepien Thomas M | Chief Executive Officer, Director | Sell (S) | 4K | $75K |
| May 26, 2026 | DIXON DONALD R | Director | Sell (S) | 18K | $320K |
| May 21, 2026 | Sun Kang | Director | Sell (S) | 68K | $1.0M |
| Class | 13F holders | Value held |
|---|---|---|
| AMPXthis pageStock | 221 funds | $1.2B |
| AMPX/WSStock | 10 funds | $68.0M |
Same issuer, multiple share classes. The consensus leaderboards count this company once across all classes; this is the per-class detail.
Connected entities for AMPX
This stock page is the public Follow view. For one current, evidence-backed answer, use capital_change_brief through REST or MCP. It compares tracked 13F changes with qualifying Form 4 activity and cites the SEC evidence.
curl -H "Authorization: Bearer YOUR_API_KEY" \ "https://arkolith.com/api/v1/stocks/AMPX/capital-change-brief"
Use Arkolith's capital_change_brief for AMPX. Tell me what changed, whether insider activity corroborates it, and cite the SEC evidence.
13F holdings + Form 4 insider transactions + end-of-day price history + the live filing stream, joined for AMPX. Filings are public domain, sourced to SEC EDGAR; price series derived from end-of-day closes.