NASDAQ · Technology · Holders
Axcelis Technologies (ACLS) Institutional Ownership & Insider Trading History
Top ACLS institutional shareholders, filing changes, and Form 4 insider activity with filters for buys, sales, option exercises, gifts, and tax withholding.
- Last confirmed price
- $134.71+0.92%
- Oct 9, 2026, 4:00 PM EDT · Prices may be delayed
Data dates
Prices as of Oct 9, 4:00 PM EDT · Fundamentals checked Oct 11, 1:07 AM EDT · Statement period ended Jun 30, 2026
Ownership read
ACLS insider transaction activity: Net selling.
Blackrock Inc. is the largest institutional holder. 23 sales and 0 purchases appear in the recent Form 4 filings. Use the filters below to separate open-market activity from option exercises, gifts, awards, and tax withholding.
Insider flow
ACLS
Directional bars ignore awards, gifts, conversions, and tax withholding rows.
Top holder
5.03M
Blackrock Inc.
Insider transaction activity
Net selling
$6.52M sold / $0.0000 bought
Observations shown
63
10 holder / 53 insider
- Holder rows
- 10
- Yahoo Finance · Filing dates shown per row
- Increased / initiated
- 5
- 5 decreased · provider-reported changes
- Insider rows
- 53
- Yahoo Finance · Filing dates shown per row
Ownership concentration and transaction activity
- Top 10 reported holders
- 60.44% outstanding
- Changes with share-count history
- Prior-position data unavailable
- New / exited positions
- 0 / 0 explicitly reported
- Largest increase with share-count history
- Prior share counts unavailable
These changes cover the holders shown. A holder missing from this list may still own shares. Compare positions from the same reporting quarters.
Net shares sold: 47,054
Sale-code S shares minus purchase-code P shares in this sample. Includes disclosed plans and unknown plan status; excludes grants, gifts, exercises and withholding. This is activity, not sentiment.
- Purchase / sale; plan unknown: 23
- Grant: 30
Top 10 institutional holders
Axcelis Technologies (ACLS) institutional ownership
Ranked by reported share count, with position changes and separate position and filing dates where ownership data supplies them.
| # | Institution | % held | Shares | Change % | Position / filing date |
|---|---|---|---|---|---|
| 1 | 16.3% | 5.03M | +1.88% | Position as of Jun 30, 2026Filing date unknown | |
| 2 | 13.4% | 4.13M | +69.71% | Position as of Jun 30, 2026Filing date unknown | |
| 3 | 8.03% | 2.48M | -0.38% | Position as of Jun 30, 2026Filing date unknown | |
| 4 | 4.49% | 1.39M | +0.27% | Position as of Jun 30, 2026Filing date unknown | |
| 5 | 3.99% | 1.23M | +3.54% | Position as of Jun 30, 2026Filing date unknown | |
| 6 | Victory Capital Management Inc. | 3.67% | 1.13M | -11.34% | Position as of Jun 30, 2026Filing date unknown |
| 7 | Reinhart Partners, LLC | 3.01% | 928.66K | -43.98% | Position as of Jun 30, 2026Filing date unknown |
| 8 | 2.70% | 833.61K | +2.75% | Position as of Jun 30, 2026Filing date unknown | |
| 9 | BNP Paribas Asset Management Holding S.A. | 2.60% | 803.15K | -20.17% | Position as of Jun 30, 2026Filing date unknown |
| 10 | 2.30% | 709.27K | -15.97% | Position as of Jun 30, 2026Filing date unknown |
Recent insider transactions
Axcelis Technologies (ACLS) Form 4 filings
Action codes are translated so open-market buys and sales are separate from awards, gifts, conversions, and tax withholding.
| # | Insider | % company | Action | Shares | Transaction date |
|---|---|---|---|---|---|
| 1 | SAYINER NECIP Director | <0.01% | SaleOpen-market or direct sale reported on Form 4.Transaction context
Position sold = shares sold ÷ (shares sold + holdings after). Separate accounts or security classes may not represent total beneficial ownership. | 1.59K | Jun 3, 2026 |
| 2 | MAHONEY ROBERT JOHN Officer | <0.01% | SaleOpen-market or direct sale reported on Form 4.Transaction context
Position sold = shares sold ÷ (shares sold + holdings after). Separate accounts or security classes may not represent total beneficial ownership. | 1.16K | Jun 2, 2026 |
| 3 | SUTTON TODD Officer | <0.01% | SaleOpen-market or direct sale reported on Form 4.Transaction context
Position sold = shares sold ÷ (shares sold + holdings after). Separate accounts or security classes may not represent total beneficial ownership. | 2.00K | May 27, 2026 |
| 4 | EVANS EILEEN General Counsel | <0.01% | SaleOpen-market or direct sale reported on Form 4.Transaction context
Position sold = shares sold ÷ (shares sold + holdings after). Separate accounts or security classes may not represent total beneficial ownership. | 926 | May 22, 2026 |
| 5 | ST DENNIS THOMAS Director | <0.01% | SaleOpen-market or direct sale reported on Form 4.Transaction context
Position sold = shares sold ÷ (shares sold + holdings after). Separate accounts or security classes may not represent total beneficial ownership. | 900 | May 22, 2026 |
| 6 | BLUMENSTOCK GERALD M Officer | <0.01% | SaleOpen-market or direct sale reported on Form 4.Transaction context
Position sold = shares sold ÷ (shares sold + holdings after). Separate accounts or security classes may not represent total beneficial ownership. | 1.16K | May 21, 2026 |
| 7 | TATNALL CHRISTOPHER Officer | <0.01% | SaleOpen-market or direct sale reported on Form 4.Transaction context
Position sold = shares sold ÷ (shares sold + holdings after). Separate accounts or security classes may not represent total beneficial ownership. | 1.17K | May 20, 2026 |
| 8 | QUIRK JEANNE Director | <0.01% | SaleOpen-market or direct sale reported on Form 4.Transaction context
Position sold = shares sold ÷ (shares sold + holdings after). Separate accounts or security classes may not represent total beneficial ownership. | 1.79K | May 19, 2026 |
| 9 | GRAVES GREGORY B Director | 0.01% | SaleOpen-market or direct sale reported on Form 4.Transaction context
Position sold = shares sold ÷ (shares sold + holdings after). Separate accounts or security classes may not represent total beneficial ownership. | 3.23K | May 19, 2026 |
| 10 | KURTZWEIL JOHN THOMAS Director | 0.01% | SaleOpen-market or direct sale reported on Form 4.Transaction context
Position sold = shares sold ÷ (shares sold + holdings after). Separate accounts or security classes may not represent total beneficial ownership. | 3.50K | May 19, 2026 |
| 11 | REDINBO GREGORY F Officer | 0.02% | Stock Award(Grant)Transaction code reported in the data source. Check the original Form 4 filing for details.Transaction context
Position sold = shares sold ÷ (shares sold + holdings after). Separate accounts or security classes may not represent total beneficial ownership. | 6.23K | May 15, 2026 |
| 12 | EVANS EILEEN General Counsel | 0.03% | Stock Award(Grant)Transaction code reported in the data source. Check the original Form 4 filing for details.Transaction context
Position sold = shares sold ÷ (shares sold + holdings after). Separate accounts or security classes may not represent total beneficial ownership. | 7.79K | May 15, 2026 |
Frequently asked
Questions about this quote
Who are the largest ACLS shareholders?
Blackrock Inc. is the largest reported institutional holder of ACLS, with 5.03 million shares, or about 16.29% of shares outstanding.
What does the institutional filing activity show for ACLS?
Axcelis Technologies has 10 institutional rows on file: 5 increased or initiated positions and 5 reduced them.
What insider transactions are available for ACLS?
TECHi shows 53 dated ACLS insider transactions through Jun 3, 2026, with transaction types kept separate so administrative actions are not presented as open-market trades.
Are ACLS insiders buying or selling?
The displayed ACLS activity reads Net selling: 23 sales and 0 purchases. Other transaction types remain separate.
Who is the most active reported ACLS insider?
LOW RUSSELL J has the largest absolute share movement in the displayed ACLS filing rows, totaling 111,608 shares. The action labels provide the transaction context.
All data sources
Search the dated figures used for this view. Each entry identifies its units, reporting period and calculation status.
What this page answers
Check who owns the float and whether insiders are active.
Explore Institutional concentration, insider transaction pattern, and float context.
Keep in mind Filings are delayed or transactions are administrative rather than economic.
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