ESSEX INVESTMENT MANAGEMENT CO LLC — 13F Holdings & Portfolio
CIK 201772 · latest 13F-HR filed 2026-05-11
ESSEX INVESTMENT MANAGEMENT CO LLC manages $631.7M in 13F-reported U.S. long-equity assets across 305 reported positions as of its 2026-03-31 13F-HR filing. Its largest disclosed positions are TSEM (3.22%), LINC (2.29%), STRL (2.07%). Quarter over quarter (versus its 2025-12-31 filing) the fund opened 28 new positions, exited 29, added to 111, and trimmed 122.
AUM is the long-equity portion reported on Form 13F-HR. Excludes short positions, cash, foreign holdings, and non-13F assets. For informational purposes only — not investment advice.
$631.7M
Long-equity book
305
Distinct positions
2026-03-31
Filed 2026-05-11
+28 / −29 / ↑111 / ↓122
vs 2025-12-31
| Name | Title / Status | Ownership | Type |
|---|
Top Adds (vs prior quarter)
- LINCOLN EDL SVCS CORP$5.1M +53.9%
- AMPRIUS TECHNOLOGIES INC$3.4M +84.2%
- LEONARDO DRS INC$2.9M +32.9%
- BIOVENTUS INC$2.6M +90.9%
- BRAINSWAY LTD$2.4M +42.1%
Top Trims
- ADAPTIVE BIOTECHNOLOGIES CORP-$3.3M -32.4%
- KRATOS DEFENSE & SEC SOLUTIONS-$3.2M -22.4%
- EVERQUOTE INC-$2.9M -46.4%
- EXZEO GROUP INC-$2.8M -40.1%
- MICROSOFT CORP-$2.7M -31.4%
New Positions
- NOVOCURE LTD$4.9M
- SYNDAX PHARMACEUTICALS INC$4.6M
- MISTRAS GROUP INC$4.0M
- MITEK SYS INC$3.7M
- MARVELL TECHNOLOGY INC$3.6M
Exited Positions
- BETA BIONICS INC$6.6M
- UNIVERSAL INS HLDGS INC$6.0M
- ANGIODYNAMICS INC$4.6M
- WINNEBAGO INDS INC$4.4M
- MAXLINEAR INC$4.1M
Rows tagged Call or Put are options positions, not stock. Per SEC Form 13F-HR, Value shows the notional value of the underlying (shares covered × underlying price), not the option premium. Shares is the number of underlying shares covered (divide by 100 for contract count).
| # | Issuer | Symbol | CUSIP | Value | Weight | Shares | Type |
|---|---|---|---|---|---|---|---|
| 1 | TOWER SEMICONDUCTOR LTD | TSEM | M87915274 | $20.3M | 3.22% | 115,933 | SH |
| 2 | LINCOLN EDL SVCS CORP | LINC | 533535100 | $14.5M | 2.29% | 355,304 | SH |
| 3 | STERLING INFRASTRUCTURE INC | STRL | 859241101 | $13.1M | 2.07% | 32,057 | SH |
| 4 | KINIKSA PHARMACEUTICALS INTL P | KNSA | G52694109 | $12.0M | 1.90% | 249,278 | SH |
| 5 | LIGAND PHARMACEUTICALS INC | LGND | 53220K504 | $11.7M | 1.85% | 58,460 | SH |
| 6 | LEONARDO DRS INC | DRS | 52661A108 | $11.6M | 1.84% | 261,454 | SH |
| 7 | KRATOS DEFENSE & SEC SOLUTIONS | KTOS | 50077B207 | $11.2M | 1.77% | 158,844 | SH |
| 8 | GLOBALSTAR INC | GSAT | 378973507 | $11.0M | 1.74% | 165,665 | SH |
| 9 | INSMED INC | INSM | 457669307 | $10.2M | 1.62% | 62,676 | SH |
| 10 | GRAHAM CORP | GHM | 384556106 | $10.1M | 1.60% | 128,294 | SH |
| 11 | MIRUM PHARMACEUTICALS INC | MIRM | 604749101 | $10.0M | 1.58% | 108,338 | SH |
| 12 | CECO ENVIRONMENTAL CORP | CECO | 125141101 | $9.4M | 1.48% | 157,246 | SH |
| 13 | HCI GROUP INC | HCI | 40416E103 | $8.9M | 1.41% | 57,634 | SH |
| 14 | ARGAN INC | AGX | 04010E109 | $8.8M | 1.39% | 16,098 | SH |
| 15 | APPLE INC | AAPL | 037833100 | $8.3M | 1.31% | 32,580 | SH |
| 16 | BRAINSWAY LTD | BWAY | 10501L106 | $8.2M | 1.30% | 618,553 | SH |
| 17 | AGNICO EAGLE MINES LTD | AEM | 008474108 | $7.8M | 1.24% | 38,643 | SH |
| 18 | AMERICAN SUPERCONDUCTOR CORP | AMSC | 030111207 | $7.7M | 1.22% | 227,558 | SH |
| 19 | AMPRIUS TECHNOLOGIES INC | AMPX | 03214Q108 | $7.5M | 1.19% | 445,441 | SH |
| 20 | GE VERNOVA INC | GEV | 36828A101 | $7.3M | 1.15% | 8,319 | SH |
| 21 | PRIMORIS SVCS CORP | PRIM | 74164F103 | $6.9M | 1.09% | 48,177 | SH |
| 22 | ADAPTIVE BIOTECHNOLOGIES CORP | ADPT | 00650F109 | $6.8M | 1.08% | 493,403 | SH |
| 23 | TETRA TECHNOLOGIES INC DEL | TTI | 88162F105 | $6.6M | 1.04% | 774,099 | SH |
| 24 | GOLDMAN SACHS GROUP INC | GS | 38141G104 | $6.4M | 1.01% | 7,556 | SH |
| 25 | WILLDAN GROUP INC | WLDN | 96924N100 | $6.0M | 0.95% | 78,292 | SH |
| 26 | COHU INC | COHU | 192576106 | $5.9M | 0.93% | 191,885 | SH |
| 27 | MICROSOFT CORP | MSFT | 594918104 | $5.8M | 0.93% | 15,791 | SH |
| 28 | MIRION TECHNOLOGIES INC | MIR | 60471A101 | $5.7M | 0.91% | 309,110 | SH |
| 29 | AMAZON COM INC | AMZN | 023135106 | $5.7M | 0.90% | 27,208 | SH |
| 30 | OCEANEERING INTL INC | OII | 675232102 | $5.6M | 0.89% | 158,374 | SH |
| 31 | ADVANCED DRAIN SYS INC DEL | WMS | 00790R104 | $5.6M | 0.88% | 40,569 | SH |
| 32 | BIOVENTUS INC | BVS | 09075A108 | $5.5M | 0.87% | 603,258 | SH |
| 33 | MAMAS CREATIONS INC | MAMA | 56146T103 | $5.2M | 0.83% | 341,657 | SH |
| 34 | BWX TECHNOLOGIES INC | BWXT | 05605H100 | $5.2M | 0.83% | 25,555 | SH |
| 35 | PATRICK INDS INC | PATK | 703343103 | $5.1M | 0.81% | 46,228 | SH |
| 36 | LSI INDS INC OHIO | LYTS | 50216C108 | $5.1M | 0.81% | 274,082 | SH |
| 37 | ORION GROUP HLDGS INC | ORN | 68628V308 | $5.0M | 0.80% | 461,772 | SH |
| 38 | NOVOCURE LTD | NVCR | G6674U108 | $4.9M | 0.78% | 452,370 | SH |
| 39 | TRAVERE THERAPEUTICS INC | TVTX | 89422G107 | $4.8M | 0.76% | 161,705 | SH |
| 40 | ARTERIS INC | AIP | 04302A104 | $4.8M | 0.76% | 290,319 | SH |
| 41 | AVEPOINT INC | AVPT | 053604104 | $4.7M | 0.75% | 498,482 | SH |
| 42 | ASML HLDG NV | ASML | N07059210 | $4.7M | 0.74% | 3,556 | SH |
| 43 | SYNDAX PHARMACEUTICALS INC | SNDX | 87164F105 | $4.6M | 0.74% | 198,985 | SH |
| 44 | CREXENDO INC | CXDO | 226552107 | $4.6M | 0.73% | 742,986 | SH |
| 45 | EVERUS CONSTR GROUP | ECG | 300426103 | $4.5M | 0.71% | 38,098 | SH |
| 46 | XERIS BIOPHARMA HOLDINGS INC | XERS | 98422E103 | $4.3M | 0.69% | 747,769 | SH |
| 47 | GLOBUS MED INC | GMED | 379577208 | $4.3M | 0.68% | 50,004 | SH |
| 48 | AMBARELLA INC | AMBA | G037AX101 | $4.2M | 0.67% | 82,387 | SH |
| 49 | EXZEO GROUP INC | XZO | 30234F101 | $4.2M | 0.67% | 288,111 | SH |
| 50 | FREQUENCY ELECTRS INC | FEIM | 358010106 | $4.1M | 0.65% | 93,026 | SH |
| Period | Filed | AUM | Holdings | Accession |
|---|---|---|---|---|
| 2026-03-31 | 2026-05-11 | $631.7M | 305 | 0000201772-26-000004 |
| 2025-12-31 | 2026-02-13 | $655.9M | 306 | 0000201772-26-000001 |
| 2025-09-30 | 2025-11-06 | $653.4M | 299 | 0000201772-25-000008 |