Ranked by reported Q1 2026 13F market value
Share of total reported institutional value in ACLS held by the largest 10 / 25 filers.
| # | Institution | Shares Held | Market Value | QoQ Change | Ownership % | % of Fund |
|---|---|---|---|---|---|---|
| 1 | BlackRock, Inc. | 4.9M | $459.5M | +2.3% | 16.063% | 0.01% |
| 2 | VANGUARD PORTFOLIO MANAGEMENT LLC | 2.5M | $231.6M | β | 8.096% | 0.01% |
| 3 | FMR LLC | 2.4M | $226.3M | +298.1% | 7.910% | 0.01% |
| 4 | REINHART PARTNERS, INC. | 1.7M | $154.3M | +4.3% | 5.394% | 4.44% |
| 5 | VANGUARD CAPITAL MANAGEMENT LLC | 1.4M | $128.7M | β | 4.499% | 0.00% |
| 6 | BALYASNY ASSET MANAGEMENT LLC | 1.4M | $127.0M | +460.4% | 4.440% | 0.44% |
| 7 | VICTORY CAPITAL MANAGEMENT INC | 1.3M | $119.0M | -29.2% | 4.162% | 0.08% |
| 8 | STATE STREET CORP | 1.2M | $110.7M | +0.2% | 3.869% | 0.00% |
| 9 | BNP Paribas Asset Management Holding S.A. | 1.0M | $93.6M | -7.8% | 3.273% | 0.11% |
| 10 | AMERICAN CENTURY COMPANIES INC | 952K | $88.6M | -22.8% | 3.097% | 0.05% |
| 11 | DIMENSIONAL FUND ADVISORS LP | 844K | $78.6M | +0.4% | 2.747% | 0.02% |
| 12 | GEODE CAPITAL MANAGEMENT, LLC | 811K | $75.5M | -11.6% | 2.640% | 0.00% |
| 13 | PRIMECAP MANAGEMENT CO/CA/ | 659K | $61.3M | -0.9% | 2.143% | 0.05% |
| 14 | MORGAN STANLEY | 582K | $54.1M | +66.1% | 1.893% | 0.00% |
| 15 | D. E. Shaw & Co., Inc. | 544K | $50.7M | +15.8% | 1.771% | 0.05% |
| 16 | GOLDMAN SACHS GROUP INC | 498K | $46.3M | -21.0% | 1.619% | 0.01% |
| 17 | MANUFACTURERS LIFE INSURANCE COMPANY, THE | 492K | $45.8M | +3402.5% | 1.600% | 0.04% |
| 18 | CHARLES SCHWAB INVESTMENT MANAGEMENT INC | 446K | $41.5M | +3.4% | 1.450% | 0.01% |
| 19 | NORTHERN TRUST CORP | 417K | $38.8M | +2.9% | 1.356% | 0.01% |
| 20 | Boston Trust Walden Corp | 379K | $35.2M | -11.5% | 1.232% | 0.29% |
| 21 | UBS Group AG | 377K | $35.1M | +76.8% | 1.227% | 0.01% |
| 22 | Boston Partners | 340K | $31.8M | -19.4% | 1.107% | 0.03% |
| 23 | Grantham, Mayo, Van Otterloo & Co. LLC | 335K | $31.2M | +3.7% | 1.089% | 0.08% |
| 24 | Allspring Global Investments Holdings, LLC | 259K | $24.7M | -2.8% | 0.841% | 0.04% |
| 25 | SEGALL BRYANT & HAMILL, LLC | 228K | $19.6M | +122.8% | 0.741% | 0.32% |
denotes a marquee investor (Buffett, Burry, ARK, Tiger Global, Pershing Square, Baupost and other widely-followed managers). β% of Fundβ shows how much of that investorβs total 13F portfolio is invested in ACLS β a direct measure of their conviction.
Filings activity in ACLS during Q1 2026, grouped by how each filer changed its position.
Institutions that opened a new ACLS position in Q1 2026
Institutions that fully closed their ACLS position in Q1 2026
8 quarters of 13F filings Β· Ξ columns show change vs prior quarter
| Quarter | Inst. Holders | Ξ Holders | Ownership % | Ξ Ownership | Total 13F Value | Ξ Value |
|---|---|---|---|---|---|---|
| Q1 2026 | 365 | +0.3% | 52.92% | +10.10 pp | $2.93B | +24% |
| Q4 2025 | 364 | +3.7% | 42.82% | 7.61 pp | $2.37B | 15% |
| Q3 2025 | 351 | +8.7% | 50.43% | +12.47 pp | $2.79B | +33% |
| Q2 2025 | 323 | +8.0% | 37.96% | +12.02 pp | $2.10B | +46% |
| Q1 2025 | 299 | 6.6% | 25.94% | 11.69 pp | $1.44B | 31% |
| Q4 2024 | 320 | 11% | 37.63% | 15.74 pp | $2.08B | 29% |
| Q3 2024 | 358 | 6.8% | 53.37% | 22.13 pp | $2.95B | 29% |
| Q2 2024 | 384 | β | 75.50% | β | $4.18B | β |
Source: SEC 13F institutional filings. Ownership % requires market cap data and will show once linked. Ξ columns compare to the immediately prior filed quarter.
Quick answers to the most common questions about buying ACLS stock.
Based on Q1 2026 13F filings, institutional ownership of Axcelis Technologies, Inc. stands at 52.9%, held across 365 reporting institutions.
BlackRock, Inc. is the largest reported institutional holder of ACLS, with approximately 4,936,774 shares worth $0.46B as of Q1 2026.
No marquee "smart money" managers (Berkshire, Burry, ARK, Tiger Global, Pershing Square, Baupost, etc.) currently appear among the top 25 institutional holders of ACLS.
Our composite Smart Money Score for ACLS is 47 out of 100 (Neutral). It combines net institutional buying activity, ownership shift, marquee investor presence, and holder-count growth.
69 institutions opened new positions in ACLS during Q1 2026, while 68 fully exited. 224 added to existing positions and 69 trimmed.
ACLS institutional ownership rose by 10.10 percentage points quarter-over-quarter, with a net change of +1 holders.
The top 10 institutions account for 59.4% of all reported 13F value in ACLS, and the top 25 account for 82.2%.
All data is sourced from SEC Form 13F filings, which institutional investment managers with at least $100M in assets are required to file each quarter. We process every 13F filing from EDGAR and recompute the aggregates after each cycle. Insider transactions are sourced from Form 4 filings.
Axcelis Technologies, Inc. (ACLS) Institutional Ownership