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NASDAQ · TECHNOLOGY · Holders

Axcelis Technologies Inc (ACLS) Institutional Ownership & Insider Trading History

Recent insider purchases and sales for ACLS from Form 4 filings. Institutional holdings surface here when ownership sources publish.

Section freshness

Price Jun 26, 4:00 PM EDT · Statements Mar 30, 8:00 PM EDT

Source timingDetails

Data freshness

Prices update fastest. Fundamentals, analyst data, and news update on their own schedules, so check these timestamps before comparing signals.

Price time means the latest available trade or regular-market close. Other times show when that section was checked or published.

PriceLive
Last traded
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Ownership read

ACLS insider sentiment: Net selling.

23 sales and 0 purchases appear in the recent Form 4 filings. Use the filters below to separate real buying and selling from option exercises, gifts, awards, and tax withholding.

Insider flow

ACLS

Purchases
Sales806.13K

Directional bars ignore awards, gifts, conversions, and tax withholding rows.

Top holder

Institutional data pending

Insider stance

Net selling

$103.60M sold / — bought

Latest filing

Jun 15, 2026

Most recent holder or insider filing date

Filings shown

83

0 holder / 83 insider

Holder rows
Pending
Market data source
Latest filing
Jun 15, 2026
Most recent holder or insider filing date
Increased / initiated
Pending
0 decreased
Insider rows
83
Market data source

Recent insider transactions

Axcelis Technologies Inc (ACLS) Form 4 filings

Action codes are translated so open-market buys and sales are separate from awards, gifts, conversions, and tax withholding.

Blumenstock Gerald M

Tax withholdingShares withheld to cover tax obligations. Usually administrative, not an open-market sale.
Shares
19.99K
% company
0.07%
Price
$191.60
Value
$3,829,509

Filed Jun 15, 2026

Sayiner Necip

SaleOpen-market or direct sale reported on Form 4.
Shares
7.11K
% company
0.02%
Price
$157.44
Value
$1,119,729

Filed Jun 3, 2026

Mahoney Robert John

SaleOpen-market or direct sale reported on Form 4.
Shares
14.41K
% company
0.05%
Price
$155.24
Value
$2,237,008

Filed Jun 2, 2026

Sutton Todd

SaleOpen-market or direct sale reported on Form 4.
Shares
6.36K
% company
0.02%
Price
$159.99
Value
$1,017,536

Filed May 27, 2026

St Dennis Thomas

SaleOpen-market or direct sale reported on Form 4.
Shares
17.70K
% company
0.06%
Price
$155.37
Value
$2,749,272

Filed May 22, 2026

Evans Eileen

SaleOpen-market or direct sale reported on Form 4.
Shares
31.30K
% company
0.10%
Price
$155.51
Value
$4,866,538

Filed May 22, 2026

Blumenstock Gerald M

SaleOpen-market or direct sale reported on Form 4.
Shares
20.49K
% company
0.07%
Price
$152.70
Value
$3,129,281

Filed May 21, 2026

Tatnall Christopher

SaleOpen-market or direct sale reported on Form 4.
Shares
27.63K
% company
0.09%
Price
$149.75
Value
$4,137,143

Filed May 20, 2026

Quirk Jeanne

SaleOpen-market or direct sale reported on Form 4.
Shares
11.40K
% company
0.04%
Price
$140.22
Value
$1,598,508

Filed May 19, 2026

GRAVES GREGORY B

SaleOpen-market or direct sale reported on Form 4.
Shares
5.47K
% company
0.02%
Price
$142.51
Value
$779,982

Filed May 19, 2026

GRAVES GREGORY B

SaleOpen-market or direct sale reported on Form 4.
Shares
6.07K
% company
0.02%
Price
$141.41
Value
$858,753

Filed May 19, 2026

KURTZWEIL JOHN T

SaleOpen-market or direct sale reported on Form 4.
Shares
32.99K
% company
0.11%
Price
$138.79
Value
$4,578,738

Filed May 19, 2026

Sutton Todd

Tax withholdingShares withheld to cover tax obligations. Usually administrative, not an open-market sale.
Shares
8.36K
% company
0.03%
Price
$146.24
Value
$1,222,566

Filed May 18, 2026

Mahoney Robert John

Tax withholdingShares withheld to cover tax obligations. Usually administrative, not an open-market sale.
Shares
15.56K
% company
0.05%
Price
$146.24
Value
$2,276,226

Filed May 18, 2026

Mahoney Robert John

Tax withholdingShares withheld to cover tax obligations. Usually administrative, not an open-market sale.
Shares
15.70K
% company
0.05%
Price
$146.24
Value
$2,295,237

Filed May 18, 2026

Redinbo Greg

Tax withholdingShares withheld to cover tax obligations. Usually administrative, not an open-market sale.
Shares
35.02K
% company
0.11%
Price
$146.24
Value
$5,121,910

Filed May 18, 2026

Redinbo Greg

Tax withholdingShares withheld to cover tax obligations. Usually administrative, not an open-market sale.
Shares
35.10K
% company
0.11%
Price
$146.24
Value
$5,133,463

Filed May 18, 2026

Low Russell

Tax withholdingShares withheld to cover tax obligations. Usually administrative, not an open-market sale.
Shares
154.90K
% company
0.50%
Price
$146.24
Value
$22,652,576

Filed May 18, 2026

Sutton Todd

Tax withholdingShares withheld to cover tax obligations. Usually administrative, not an open-market sale.
Shares
8.54K
% company
0.03%
Price
$155.18
Value
$1,325,858

Filed May 15, 2026

Sutton Todd

Tax withholdingShares withheld to cover tax obligations. Usually administrative, not an open-market sale.
Shares
8.65K
% company
0.03%
Price
$155.18
Value
$1,341,841

Filed May 15, 2026

Sutton Todd

Tax withholdingShares withheld to cover tax obligations. Usually administrative, not an open-market sale.
Shares
8.76K
% company
0.03%
Price
$155.18
Value
$1,359,222

Filed May 15, 2026

Sutton Todd

Award / grantAward, grant, or acquisition under an equity compensation plan.
Shares
8.98K
% company
0.03%
Price
No cash value
Value
No cash value

Filed May 15, 2026

Ryzhik David

Tax withholdingShares withheld to cover tax obligations. Usually administrative, not an open-market sale.
Shares
10.03K
% company
0.03%
Price
$155.18
Value
$1,556,611

Filed May 15, 2026

Ryzhik David

Award / grantAward, grant, or acquisition under an equity compensation plan.
Shares
10.26K
% company
0.03%
Price
No cash value
Value
No cash value

Filed May 15, 2026

Mahoney Robert John

Tax withholdingShares withheld to cover tax obligations. Usually administrative, not an open-market sale.
Shares
15.88K
% company
0.05%
Price
$155.18
Value
$2,463,793

Filed May 15, 2026

Mahoney Robert John

Tax withholdingShares withheld to cover tax obligations. Usually administrative, not an open-market sale.
Shares
15.94K
% company
0.05%
Price
$155.18
Value
$2,473,259

Filed May 15, 2026

Mahoney Robert John

Tax withholdingShares withheld to cover tax obligations. Usually administrative, not an open-market sale.
Shares
16.11K
% company
0.05%
Price
$155.18
Value
$2,499,639

Filed May 15, 2026

Mahoney Robert John

Tax withholdingShares withheld to cover tax obligations. Usually administrative, not an open-market sale.
Shares
16.28K
% company
0.05%
Price
$155.18
Value
$2,526,486

Filed May 15, 2026

Mahoney Robert John

Award / grantAward, grant, or acquisition under an equity compensation plan.
Shares
16.65K
% company
0.05%
Price
No cash value
Value
No cash value

Filed May 15, 2026

Mahoney Robert John

Award / grantAward, grant, or acquisition under an equity compensation plan.
Shares
14.71K
% company
0.05%
Price
No cash value
Value
No cash value

Filed May 15, 2026

Tatnall Christopher

Tax withholdingShares withheld to cover tax obligations. Usually administrative, not an open-market sale.
Shares
28.79K
% company
0.09%
Price
$155.18
Value
$4,468,098

Filed May 15, 2026

Tatnall Christopher

Tax withholdingShares withheld to cover tax obligations. Usually administrative, not an open-market sale.
Shares
28.96K
% company
0.09%
Price
$155.18
Value
$4,494,478

Filed May 15, 2026

Tatnall Christopher

Tax withholdingShares withheld to cover tax obligations. Usually administrative, not an open-market sale.
Shares
29.31K
% company
0.10%
Price
$155.18
Value
$4,548,015

Filed May 15, 2026

Tatnall Christopher

Award / grantAward, grant, or acquisition under an equity compensation plan.
Shares
30.05K
% company
0.10%
Price
No cash value
Value
No cash value

Filed May 15, 2026

Tatnall Christopher

Award / grantAward, grant, or acquisition under an equity compensation plan.
Shares
26.55K
% company
0.09%
Price
No cash value
Value
No cash value

Filed May 15, 2026

Blumenstock Gerald M

Tax withholdingShares withheld to cover tax obligations. Usually administrative, not an open-market sale.
Shares
21.65K
% company
0.07%
Price
$155.18
Value
$3,360,268

Filed May 15, 2026

Blumenstock Gerald M

Tax withholdingShares withheld to cover tax obligations. Usually administrative, not an open-market sale.
Shares
22.00K
% company
0.07%
Price
$155.18
Value
$3,413,805

Filed May 15, 2026

Blumenstock Gerald M

Award / grantAward, grant, or acquisition under an equity compensation plan.
Shares
22.74K
% company
0.07%
Price
No cash value
Value
No cash value

Filed May 15, 2026

Blumenstock Gerald M

Award / grantAward, grant, or acquisition under an equity compensation plan.
Shares
20.02K
% company
0.07%
Price
No cash value
Value
No cash value

Filed May 15, 2026

Redinbo Greg

Tax withholdingShares withheld to cover tax obligations. Usually administrative, not an open-market sale.
Shares
35.21K
% company
0.11%
Price
$155.18
Value
$5,464,509

Filed May 15, 2026

Redinbo Greg

Tax withholdingShares withheld to cover tax obligations. Usually administrative, not an open-market sale.
Shares
35.39K
% company
0.12%
Price
$155.18
Value
$5,491,975

Filed May 15, 2026

Redinbo Greg

Tax withholdingShares withheld to cover tax obligations. Usually administrative, not an open-market sale.
Shares
35.60K
% company
0.12%
Price
$155.18
Value
$5,524,563

Filed May 15, 2026

Redinbo Greg

Award / grantAward, grant, or acquisition under an equity compensation plan.
Shares
36.05K
% company
0.12%
Price
No cash value
Value
No cash value

Filed May 15, 2026

Redinbo Greg

Award / grantAward, grant, or acquisition under an equity compensation plan.
Shares
32.94K
% company
0.11%
Price
No cash value
Value
No cash value

Filed May 15, 2026

Evans Eileen

Tax withholdingShares withheld to cover tax obligations. Usually administrative, not an open-market sale.
Shares
32.22K
% company
0.10%
Price
$155.18
Value
$5,000,055

Filed May 15, 2026

Evans Eileen

Award / grantAward, grant, or acquisition under an equity compensation plan.
Shares
33.09K
% company
0.11%
Price
No cash value
Value
No cash value

Filed May 15, 2026

Evans Eileen

Award / grantAward, grant, or acquisition under an equity compensation plan.
Shares
29.20K
% company
0.09%
Price
No cash value
Value
No cash value

Filed May 15, 2026

Low Russell

Tax withholdingShares withheld to cover tax obligations. Usually administrative, not an open-market sale.
Shares
155.61K
% company
0.51%
Price
$155.18
Value
$24,147,715

Filed May 15, 2026

Low Russell

Tax withholdingShares withheld to cover tax obligations. Usually administrative, not an open-market sale.
Shares
157.06K
% company
0.51%
Price
$155.18
Value
$24,373,192

Filed May 15, 2026

Low Russell

Tax withholdingShares withheld to cover tax obligations. Usually administrative, not an open-market sale.
Shares
158.79K
% company
0.52%
Price
$155.18
Value
$24,640,411

Filed May 15, 2026

Low Russell

Award / grantAward, grant, or acquisition under an equity compensation plan.
Shares
162.50K
% company
0.53%
Price
No cash value
Value
No cash value

Filed May 15, 2026

Low Russell

Award / grantAward, grant, or acquisition under an equity compensation plan.
Shares
143.04K
% company
0.47%
Price
No cash value
Value
No cash value

Filed May 15, 2026

Quirk Jeanne

Award / grantAward, grant, or acquisition under an equity compensation plan.
Shares
13.19K
% company
0.04%
Price
No cash value
Value
No cash value

Filed May 15, 2026

Chiu Tzu Yin

Award / grantAward, grant, or acquisition under an equity compensation plan.
Shares
11.84K
% company
0.04%
Price
No cash value
Value
No cash value

Filed May 15, 2026

Titinger Jorge

Award / grantAward, grant, or acquisition under an equity compensation plan.
Shares
5.92K
% company
0.02%
Price
No cash value
Value
No cash value

Filed May 15, 2026

St Dennis Thomas

Award / grantAward, grant, or acquisition under an equity compensation plan.
Shares
18.59K
% company
0.06%
Price
No cash value
Value
No cash value

Filed May 15, 2026

Sayiner Necip

Award / grantAward, grant, or acquisition under an equity compensation plan.
Shares
8.70K
% company
0.03%
Price
No cash value
Value
No cash value

Filed May 15, 2026

GRAVES GREGORY B

Award / grantAward, grant, or acquisition under an equity compensation plan.
Shares
8.70K
% company
0.03%
Price
No cash value
Value
No cash value

Filed May 15, 2026

KURTZWEIL JOHN T

Award / grantAward, grant, or acquisition under an equity compensation plan.
Shares
36.49K
% company
0.12%
Price
No cash value
Value
No cash value

Filed May 15, 2026

Sutton Todd

SaleOpen-market or direct sale reported on Form 4.
Shares
7.82K
% company
0.03%
Price
$163.89
Value
$1,281,164

Filed May 14, 2026

Blumenstock Gerald M

SaleOpen-market or direct sale reported on Form 4.
Shares
17.29K
% company
0.06%
Price
$162.32
Value
$2,806,913

Filed May 14, 2026

Redinbo Greg

SaleOpen-market or direct sale reported on Form 4.
Shares
29.82K
% company
0.10%
Price
$160.85
Value
$4,797,030

Filed May 13, 2026

Titinger Jorge

SaleOpen-market or direct sale reported on Form 4.
Shares
4.48K
% company
0.01%
Price
$164.14
Value
$734,855

Filed May 13, 2026

Mahoney Robert John

SaleOpen-market or direct sale reported on Form 4.
Shares
12.76K
% company
0.04%
Price
$161.00
Value
$2,054,199

Filed May 12, 2026

Low Russell

SaleOpen-market or direct sale reported on Form 4.
Shares
123.57K
% company
0.40%
Price
$156.75
Value
$19,369,598

Filed May 6, 2026

Low Russell

SaleOpen-market or direct sale reported on Form 4.
Shares
131.04K
% company
0.43%
Price
$138.86
Value
$18,195,937

Filed May 1, 2026

Tatnall Christopher

Tax withholdingShares withheld to cover tax obligations. Usually administrative, not an open-market sale.
Shares
23.04K
% company
0.07%
Price
$131.02
Value
$3,019,225

Filed Apr 20, 2026

Low Russell

SaleOpen-market or direct sale reported on Form 4.
Shares
132.28K
% company
0.43%
Price
$94.06
Value
$12,442,445

Filed Apr 1, 2026

Low Russell

SaleOpen-market or direct sale reported on Form 4.
Shares
133.53K
% company
0.43%
Price
$90.00
Value
$12,017,340

Filed Mar 24, 2026

Mahoney Robert John

Tax withholdingShares withheld to cover tax obligations. Usually administrative, not an open-market sale.
Shares
14.63K
% company
0.05%
Price
$86.58
Value
$1,266,925

Filed Mar 2, 2026

Tatnall Christopher

Tax withholdingShares withheld to cover tax obligations. Usually administrative, not an open-market sale.
Shares
23.18K
% company
0.08%
Price
$86.58
Value
$2,007,184

Filed Mar 2, 2026

Blumenstock Gerald M

Tax withholdingShares withheld to cover tax obligations. Usually administrative, not an open-market sale.
Shares
17.54K
% company
0.06%
Price
$86.58
Value
$1,518,613

Filed Mar 2, 2026

Redinbo Greg

Tax withholdingShares withheld to cover tax obligations. Usually administrative, not an open-market sale.
Shares
31.94K
% company
0.10%
Price
$86.58
Value
$2,765,192

Filed Mar 2, 2026

COOGAN JAMES GORDON

Tax withholdingShares withheld to cover tax obligations. Usually administrative, not an open-market sale.
Shares
37.14K
% company
0.12%
Price
$86.58
Value
$3,215,928

Filed Mar 2, 2026

Low Russell

Tax withholdingShares withheld to cover tax obligations. Usually administrative, not an open-market sale.
Shares
130.93K
% company
0.43%
Price
$86.58
Value
$11,335,746

Filed Mar 2, 2026

Titinger Jorge

SaleOpen-market or direct sale reported on Form 4.
Shares
6.48K
% company
0.02%
Price
$80.00
Value
$518,160

Filed Feb 20, 2026

Mahoney Robert John

Award / grantAward, grant, or acquisition under an equity compensation plan.
Shares
15.21K
% company
0.05%
Price
No cash value
Value
No cash value

Filed Jan 15, 2026

Titinger Jorge

SaleOpen-market or direct sale reported on Form 4.
Shares
7.48K
% company
0.02%
Price
$86.05
Value
$643,396

Filed Dec 17, 2025

Evans Eileen

Tax withholdingShares withheld to cover tax obligations. Usually administrative, not an open-market sale.
Shares
24.41K
% company
0.08%
Price
$86.32
Value
$2,106,726

Filed Dec 16, 2025

Blumenstock Gerald M

SaleOpen-market or direct sale reported on Form 4.
Shares
18.66K
% company
0.06%
Price
$89.46
Value
$1,669,413

Filed Dec 11, 2025

COOGAN JAMES GORDON

Tax withholdingShares withheld to cover tax obligations. Usually administrative, not an open-market sale.
Shares
38.94K
% company
0.13%
Price
$83.62
Value
$3,256,497

Filed Oct 16, 2025

Tatnall Christopher

Tax withholdingShares withheld to cover tax obligations. Usually administrative, not an open-market sale.
Shares
24.30K
% company
0.08%
Price
$87.30
Value
$2,121,739

Filed Sep 15, 2025

Redinbo Greg

Tax withholdingShares withheld to cover tax obligations. Usually administrative, not an open-market sale.
Shares
32.66K
% company
0.11%
Price
$87.30
Value
$2,851,305

Filed Sep 15, 2025

Showing 83 of 83 matching Form 4 rows. Percent of company uses current shares outstanding when available.

Frequently asked

Common questions.

Who are the largest ACLS shareholders?

Axcelis Technologies Inc (ACLS) institutional holders are ranked by reported share count when ownership data publishes filing rows.

What is institutional ownership of ACLS?

Axcelis Technologies Inc (ACLS) institutional ownership appears when filing-based market data returns holder rows. TECHi does not fill unavailable ownership fields with placeholder shareholders.

Where can I see Axcelis Technologies Inc insider transactions?

Axcelis Technologies Inc (ACLS) has 83 Form 4 insider transactions on file, most recently on Jun 15, 2026, separated into purchases, sales, option exercises, awards, gifts, and tax withholding so administrative transactions are distinguished from open-market trades.

Are ACLS insiders buying or selling?

Recent ACLS insider activity reads Net selling: 23 sales and 0 purchases. Awards, gifts, conversions, and tax withholding are listed separately because they do not carry the same signal as open-market trades.

Who is the most active ACLS insider?

Low Russell is the most active ACLS insider by absolute share movement, with 1.58 million shares moving across the filing history. Review the action labels before treating that activity as buying or selling.