Essex Investment Management Co. LLC
In its 13F for Q1 2026 (holdings as of March 31, 2026, filed May 11, 2026), Essex Investment Management Co. LLC reported 305 stock positions worth $631.7 million. Its top holding was Tower Semiconductor (TSEM) at 3.2% of the portfolio, followed by Lincoln Educational Services (LINC, 2.3%) and Sterling Infrastructure (STRL, 2.1%). Compared with Q4 2025, it opened 27 new positions, sold out of 28, added to 83 and reduced 86. The biggest buy was a new position in Novocure (NVCR) and the biggest sale an exit from Beta Bionics (BBNX).
- Most Recent 13F
- Q2 2026
- Location
- BOSTON, MA
- CIK
- 0000201772
- Portfolio Value
- $631.7M (Q1 2026)
- SEC Filing
- 0000201772-26-000004 ↗ filed May 11, 2026
Holdings Value
Holdings 305 stocks · $631.7M
| TSEM Tower Semiconductor Ltd. | 3.22% | 115,933 | $20.3M | Reduce -39.8% |
| LINC Lincoln Educational Services | 2.29% | 355,304 | $14.5M | Reduce -8.6% |
| STRL Sterling Infrastructure Inc. | 2.07% | 32,057 | $13.1M | Reduce -28.3% |
| KNSA Kiniksa Pharmaceuticals Inte | 1.90% | 249,278 | $12.0M | Reduce -0.7% |
| LGND Ligand Pharmaceuticals | 1.85% | 58,460 | $11.7M | Reduce -2.6% |
| DRS Leonardo DRS Inc. | 1.84% | 261,454 | $11.6M | Add +1.8% |
| KTOS Kratos Defense & Security | 1.77% | 158,844 | $11.2M | Reduce -16.5% |
| GSAT Globalstar Inc. | 1.74% | 165,665 | $11.0M | Reduce -1.0% |
| INSM Insmed Inc. | 1.62% | 62,676 | $10.2M | Add +0.4% |
| GHM Graham Corp. | 1.60% | 128,294 | $10.1M | Reduce -8.8% |
| MIRM Mirum Pharmaceuticals Inc. | 1.58% | 108,338 | $10.0M | Reduce -2.7% |
| CECO Ceco Environmental Corp. | 1.48% | 157,246 | $9.4M | Add +1.8% |
| HCI Hci Group Inc. | 1.41% | 57,634 | $8.9M | Reduce -2.7% |
| AGX Argan Inc. | 1.39% | 16,098 | $8.8M | Reduce -41.7% |
| AAPL Apple Inc. | 1.31% | 32,580 | $8.3M | Reduce -6.6% |
| BWAY Brainsway Ltd.-ADR | 1.30% | 618,553 | $8.2M | Add +1.7% |
| AEM Agnico Eagle Mines Ltd. | 1.24% | 38,643 | $7.8M | Reduce -3.5% |
| AMSC American Superconductor Corp. | 1.22% | 227,558 | $7.7M | Add +5.8% |
| AMPX Amprius Technologies Inc. | 1.19% | 445,441 | $7.5M | Reduce -13.8% |
| GEV GE Vernova Inc. | 1.15% | 8,319 | $7.3M | Reduce -3.3% |
| PRIM Primoris Services Corp. | 1.09% | 48,177 | $6.9M | Reduce -5.5% |
| ADPT Adaptive Biotechnologies | 1.08% | 493,403 | $6.8M | Reduce -21.0% |
| TTI Tetra Technologies Inc. | 1.04% | 774,099 | $6.6M | Add +1.8% |
| GS Goldman Sachs Group Inc. | 1.01% | 7,556 | $6.4M | Reduce -12.7% |
| WLDN Willdan Group Inc. | 0.95% | 78,292 | $6.0M | Add +1.8% |
| COHU Cohu Inc. | 0.93% | 191,885 | $5.9M | Add +1.8% |
| MSFT Microsoft Corp. | 0.93% | 15,791 | $5.8M | Reduce -10.3% |
| MIR Mirion Technologies Inc. | 0.91% | 309,110 | $5.7M | Add +1.9% |
| AMZN Amazon.com Inc. | 0.90% | 27,208 | $5.7M | Reduce -5.6% |
| OII Oceaneering Intl Inc. | 0.89% | 158,374 | $5.6M | Add +1.9% |
| WMS Advanced Drainage Systems Inc. | 0.88% | 40,569 | $5.6M | Reduce -5.3% |
| BVS Bioventus Inc. Class A | 0.87% | 603,258 | $5.5M | Add +55.5% |
| MAMA Mama's Creations Inc. | 0.83% | 341,657 | $5.2M | Add +1.8% |
| BWXT BWX Technologies Inc. | 0.83% | 25,555 | $5.2M | Reduce -6.2% |
| PATK Patrick Industries Inc. | 0.81% | 46,228 | $5.1M | Add +0.6% |
| LYTS Lsi Industries Inc. | 0.81% | 274,082 | $5.1M | Add +1.8% |
| ORN Orion Group Holdings Inc. | 0.80% | 461,772 | $5.0M | Add +2.7% |
| NVCR Novocure Ltd. | 0.78% | 452,370 | $4.9M | New |
| TVTX Travere Therapeutics Inc. | 0.76% | 161,705 | $4.8M | Add +1.9% |
| AIP Arteris Inc. | 0.76% | 290,319 | $4.8M | Add +1.8% |
| AVPT Avepoint Inc. | 0.75% | 498,482 | $4.7M | Reduce -1.9% |
| ASML ASML Holding NV-NY Reg SHS filed as ASML HLDG NV | 0.74% | 3,556 | $4.7M | Reduce -6.6% |
| SNDX Syndax Pharmaceuticals Inc. | 0.74% | 198,985 | $4.6M | New |
| CXDO Crexendo Inc. | 0.73% | 742,986 | $4.6M | Add +1.8% |
| ECG Everus Construction Group | 0.71% | 38,098 | $4.5M | Add +1.9% |
| XERS Xeris Biopharma Holdings Inc. | 0.69% | 747,769 | $4.3M | Add +1.8% |
| GMED Globus Medical Inc. Class A | 0.68% | 50,004 | $4.3M | Reduce -2.7% |
| AMBA Ambarella Inc. | 0.67% | 82,387 | $4.2M | Reduce -1.7% |
| XZO Exzeo Group Inc. | 0.67% | 288,111 | $4.2M | Reduce -1.0% |
| FEIM Frequency Electronics Inc. | 0.65% | 93,026 | $4.1M | Add +1.8% |
| JAZZ Jazz Pharmaceuticals PLC | 0.65% | 21,778 | $4.1M | Reduce -6.1% |
| PKE Park Aerospace Corp. | 0.65% | 149,893 | $4.1M | Add +1.8% |
| MG Mistras Group Inc. | 0.63% | 268,567 | $4.0M | New |
| SMTC Semtech Corp. | 0.62% | 50,644 | $3.9M | Add +1.9% |
| IDN Intellicheck Inc. | 0.60% | 537,842 | $3.8M | Add +67.1% |
| MITK Mitek Systems Inc. | 0.59% | 275,602 | $3.7M | New |
| MRVL Marvell Technology Inc. | 0.57% | 36,203 | $3.6M | New |
| DAKT Daktronics Inc. | 0.56% | 182,086 | $3.6M | Add +1.8% |
| AGIO Agios Pharmaceuticals Inc. | 0.55% | 103,177 | $3.5M | New |
| AMTB Amerant Bancorp Inc. | 0.55% | 156,818 | $3.5M | Add +1.8% |
| SOPH Sophia Genetics SA | 0.54% | 692,809 | $3.4M | New |
| BKSY Blacksky Technology Inc. | 0.54% | 136,104 | $3.4M | Add +1.8% |
| GFF Griffon Corp. | 0.54% | 47,076 | $3.4M | Add +1.9% |
| ARQT Arcutis Biotherapeutics Inc. | 0.54% | 143,934 | $3.4M | Add +1.9% |
| OUST Ouster Inc. | 0.54% | 184,585 | $3.4M | Add +1.8% |
| EVER Everquote Inc. Class A | 0.53% | 217,075 | $3.3M | Reduce -6.2% |
| BKR Baker Hughes Co. | 0.53% | 54,682 | $3.3M | Reduce -6.8% |
| DIOD Diodes Inc. | 0.53% | 48,869 | $3.3M | New |
| CRM Salesforce Inc. | 0.53% | 17,854 | $3.3M | Reduce -6.4% |
| OCUL Ocular Therapeutix Inc. | 0.53% | 392,718 | $3.3M | Add +1.8% |
| APYX Apyx Medical Corp. | 0.53% | 901,398 | $3.3M | New |
| LQDT Liquidity Services Inc. | 0.52% | 108,004 | $3.3M | Add +1.8% |
| BGC BGC Group Inc. Class A | 0.52% | 336,781 | $3.3M | Add +1.9% |
| DLTR Dollar Tree Inc. | 0.51% | 29,614 | $3.2M | Reduce -6.8% |
| CON Concentra Group Holdings Par | 0.51% | 149,625 | $3.2M | Reduce -6.9% |
| PEGA Pegasystems Inc. | 0.50% | 74,445 | $3.2M | Reduce -6.3% |
| GWRE Guidewire Software Inc. | 0.50% | 21,153 | $3.2M | Reduce -6.0% |
| RSKD Riskified Ltd. Class A | 0.50% | 803,032 | $3.1M | New |
| THRM Gentherm Inc. | 0.50% | 113,138 | $3.1M | Add +1.9% |
| CMCO Columbus McKinnon Corp. | 0.49% | 211,707 | $3.1M | Add +1.8% |
| DCBO Docebo Inc. | 0.48% | 172,367 | $3.0M | Add +70.7% |
| MASS 908 Devices Inc. | 0.48% | 491,221 | $3.0M | Add +1.8% |
| VREX Varex Imaging Corp. | 0.47% | 279,551 | $3.0M | Add +1.9% |
| LQDA Liquidia Corp. | 0.47% | 78,171 | $3.0M | New |
| STXS Stereotaxis Inc. | 0.46% | 1,590,101 | $2.9M | Add +1.8% |
| JOUT Johnson Outdoors Inc. Class A | 0.46% | 62,864 | $2.9M | New |
| NPCE Neuropace Inc. | 0.45% | 217,738 | $2.9M | Add +1.8% |
| RAIL Freightcar America Inc. | 0.44% | 352,343 | $2.8M | Add +1.8% |
| INFU Infusystem Holdings Inc. | 0.44% | 299,332 | $2.8M | Add +1.8% |
| AXSM Axsome Therapeutics Inc. | 0.44% | 16,328 | $2.8M | Reduce -6.1% |
| ARLO Arlo Technologies Inc. | 0.43% | 192,504 | $2.7M | Add +1.9% |
| INVE Inve Technologies Inc. filed as IDENTIV INC | 0.43% | 736,608 | $2.7M | Add +1.8% |
| SIBN Si-Bone Inc. | 0.42% | 212,488 | $2.7M | Add +1.8% |
| TRMB Trimble Inc. | 0.42% | 40,964 | $2.7M | Reduce -6.1% |
| EVR Evercore Inc. Class A | 0.42% | 8,939 | $2.7M | Add +1.9% |
| XPRO Expro Group Holdings NV | 0.41% | 150,315 | $2.6M | Add +1.9% |
| CCLD Carecloud Inc. | 0.40% | 697,836 | $2.5M | Add +1.9% |
| MTDR Matador Resources Co. | 0.40% | 39,998 | $2.5M | Add +2.0% |
| NOVT Novanta Inc. | 0.39% | 20,703 | $2.4M | Add +1.8% |
| ONT Onterris Inc. filed as MONTROSE ENVIRONMENTAL GROUP | 0.39% | 111,473 | $2.4M | Add +1.8% |
Portfolio Sells Q4 2025 → Q1 2026
| BBNX Beta Bionics Inc. | Sold out | 0.00% | −1.01 |
| UVE Universal Insurance Holdings | Sold out | 0.00% | −0.91 |
| ANGO Angiodynamics Inc. | Sold out | 0.00% | −0.71 |
| WGO Winnebago Industries | Sold out | 0.00% | −0.68 |
| MXL Maxlinear Inc. | Sold out | 0.00% | −0.63 |
| GLDD Great Lakes Dredge & Dock Co. | Sold out | 0.00% | −0.60 |
| ADPT Adaptive Biotechnologies | Reduce -21.0% | 1.08% | −0.46 |
| RDCM Radcom Ltd. | Sold out | 0.00% | −0.46 |
| CRNT Ceragon Networks Ltd. | Sold out | 0.00% | −0.45 |
| KTOS Kratos Defense & Security | Reduce -16.5% | 1.77% | −0.43 |
| EVER Everquote Inc. Class A | Reduce -6.2% | 0.53% | −0.42 |
| XZO Exzeo Group Inc. | Reduce -1.0% | 0.67% | −0.41 |
| DERM Journey Medical Corp. | Sold out | 0.00% | −0.41 |
| LZ Legalzoomcom Inc. | Sold out | 0.00% | −0.41 |
| MSFT Microsoft Corp. | Reduce -10.3% | 0.93% | −0.37 |
| PROF Profound Medical Corp. | Sold out | 0.00% | −0.37 |
| AVPT Avepoint Inc. | Reduce -1.9% | 0.75% | −0.33 |
| HCI Hci Group Inc. | Reduce -2.7% | 1.41% | −0.32 |
| FSLR First Solar Inc. | Sold out | 0.00% | −0.32 |
| IFNNF Infineon Technologies AG | Sold out | 0.00% | −0.30 |
| CTM Castellum Inc. | Sold out | 0.00% | −0.29 |
| PHR Phreesia Inc. | Sold out | 0.00% | −0.26 |
| CRM Salesforce Inc. | Reduce -6.4% | 0.53% | −0.24 |
| SLND Southland Holdings Inc. | Sold out | 0.00% | −0.24 |
| AMBA Ambarella Inc. | Reduce -1.7% | 0.67% | −0.23 |
| TSEM Tower Semiconductor Ltd. | Reduce -39.8% | 3.22% | −0.23 |
| PEGA Pegasystems Inc. | Reduce -6.3% | 0.50% | −0.22 |
| BLDR Builders Firstsource Inc. | Sold out | 0.00% | −0.21 |
| INTU Intuit Inc. | Reduce -35.4% | 0.15% | −0.19 |
| GWRE Guidewire Software Inc. | Reduce -6.0% | 0.50% | −0.19 |
| WK Workiva Inc. | Reduce -8.1% | 0.34% | −0.18 |
| ZS Zscaler Inc. | Reduce -6.8% | 0.25% | −0.17 |
| AXP American Express Co. | Reduce -69.3% | 0.06% | −0.17 |
| GS Goldman Sachs Group Inc. | Reduce -12.7% | 1.01% | −0.15 |
| AAPL Apple Inc. | Reduce -6.6% | 1.31% | −0.14 |
| PAYX Paychex Inc. | Reduce -34.4% | 0.16% | −0.13 |
| PRLB Proto Labs Inc. | Sold out | 0.00% | −0.12 |
| AMZN Amazon.com Inc. | Reduce -5.6% | 0.90% | −0.12 |
| DE Deere & Co. | Sold out | 0.00% | −0.10 |
| TRMB Trimble Inc. | Reduce -6.1% | 0.42% | −0.10 |
| DFLI Dragonfly Energy Holdings Co. | Sold out | 0.00% | −0.09 |
| DLTR Dollar Tree Inc. | Reduce -6.8% | 0.51% | −0.08 |
| PG The Procter & Gamble Co. | Reduce -37.8% | 0.13% | −0.07 |
| OWLT Owlet Inc. | Sold out | 0.00% | −0.07 |
| ERII Energy Recovery Inc. | Reduce -2.1% | 0.21% | −0.07 |
| ARRY Array Technologies Inc. | Sold out | 0.00% | −0.07 |
| WMS Advanced Drainage Systems Inc. | Reduce -5.3% | 0.88% | −0.07 |
| VMI Valmont Industries | Reduce -27.9% | 0.18% | −0.06 |
| FLNC Fluence Energy Inc. | Reduce -33.7% | 0.06% | −0.06 |
| DIS The Walt Disney Co. | Reduce -2.6% | 0.35% | −0.06 |
Portfolio Buys Q4 2025 → Q1 2026
| NVCR Novocure Ltd. | New | 0.78% | +0.78 |
| SNDX Syndax Pharmaceuticals Inc. | New | 0.74% | +0.74 |
| MG Mistras Group Inc. | New | 0.63% | +0.63 |
| MITK Mitek Systems Inc. | New | 0.59% | +0.59 |
| MRVL Marvell Technology Inc. | New | 0.57% | +0.57 |
| AGIO Agios Pharmaceuticals Inc. | New | 0.55% | +0.55 |
| SOPH Sophia Genetics SA | New | 0.54% | +0.54 |
| DIOD Diodes Inc. | New | 0.53% | +0.53 |
| APYX Apyx Medical Corp. | New | 0.53% | +0.53 |
| DRS Leonardo DRS Inc. | Add +1.8% | 1.84% | +0.51 |
| RSKD Riskified Ltd. Class A | New | 0.50% | +0.50 |
| LQDA Liquidia Corp. | New | 0.47% | +0.47 |
| JOUT Johnson Outdoors Inc. Class A | New | 0.46% | +0.46 |
| BVS Bioventus Inc. Class A | Add +55.5% | 0.87% | +0.43 |
| BWAY Brainsway Ltd.-ADR | Add +1.7% | 1.30% | +0.42 |
| OII Oceaneering Intl Inc. | Add +1.9% | 0.89% | +0.32 |
| CODA Coda Octopus Group Inc. | Add +713.9% | 0.34% | +0.31 |
| BDSX Biodesix Inc. | New | 0.30% | +0.30 |
| RPID Rapid Micro Biosystems Inc. Class A | Add +1318.2% | 0.32% | +0.29 |
| LGCY Legacy Education Inc. | New | 0.28% | +0.28 |
| LTRX Lantronix Inc. | New | 0.28% | +0.28 |
| LPTH Lightpath Technologies Inc. Class A | Add +429.3% | 0.34% | +0.28 |
| AMSC American Superconductor Corp. | Add +5.8% | 1.22% | +0.28 |
| IDN Intellicheck Inc. | Add +67.1% | 0.60% | +0.27 |
| COHU Cohu Inc. | Add +1.8% | 0.93% | +0.26 |
| ALLT Allot Ltd. | New | 0.24% | +0.24 |
| ECG Everus Construction Group | Add +1.9% | 0.71% | +0.22 |
| PKE Park Aerospace Corp. | Add +1.8% | 0.65% | +0.17 |
| BKSY Blacksky Technology Inc. | Add +1.8% | 0.54% | +0.16 |
| MTDR Matador Resources Co. | Add +2.0% | 0.40% | +0.15 |
| MAMA Mama's Creations Inc. | Add +1.8% | 0.83% | +0.14 |
| DCBO Docebo Inc. | Add +70.7% | 0.48% | +0.13 |
| SFM Sprouts Farmers Market Inc. | New | 0.13% | +0.13 |
| ORN Orion Group Holdings Inc. | Add +2.7% | 0.80% | +0.12 |
| XPRO Expro Group Holdings NV | Add +1.9% | 0.41% | +0.11 |
| LNN Lindsay Corp. | New | 0.11% | +0.11 |
| CCLD Carecloud Inc. | Add +1.9% | 0.40% | +0.10 |
| ENPH Enphase Energy Inc. | Add +46.8% | 0.21% | +0.09 |
| MASS 908 Devices Inc. | Add +1.8% | 0.48% | +0.09 |
| AMTB Amerant Bancorp Inc. | Add +1.8% | 0.55% | +0.09 |
| NXT Nextpower Inc. | Add +23.1% | 0.20% | +0.09 |
| MWH Solv Energy Inc. Class A | New | 0.08% | +0.08 |
| AIP Arteris Inc. | Add +1.8% | 0.76% | +0.08 |
| AMBQ Ambiq Micro Inc. | New | 0.08% | +0.08 |
| ON On Semiconductor | Add +41.9% | 0.19% | +0.08 |
| ALFEN NV | New | 0.08% | +0.08 |
| CECO Ceco Environmental Corp. | Add +1.8% | 1.48% | +0.07 |
| BGC BGC Group Inc. Class A | Add +1.9% | 0.52% | +0.07 |
| CARR Carrier Global Corp. | Add +43.1% | 0.18% | +0.07 |
| GENC Gencor Industries Inc. | Add +2.7% | 0.31% | +0.06 |
All Filings
| Quarter | Positions | 13F Reported Value | Top Holdings |
|---|---|---|---|
| Q2 2026 | 306 | $763.4M | TSEM, LINC, KNSA, OUST, LGND |
| Q1 2026 | 305 | $631.7M | TSEM, LINC, STRL, KNSA, LGND |
| Q4 2025 | 306 | $655.9M | TSEM, KTOS, STRL, HCI, LGND |
| Q3 2025 | 299 | $653.4M | KTOS, STRL, AMSC, TSEM, INSM |
| Q2 2025 | 298 | $550.0M | KTOS, AMSC, STRL, DRS, AVPT |
| Q1 2025 | 303 | $479.4M | HCI, KTOS, DRS, AAPL, NEE |
| Q4 2024 | 307 | $556.1M | PRIM, AMSC, AAPL, KTOS, HCI |
| Q3 2024 | 302 | $573.7M | AMSC, DRS, AAPL, HCI, NEE |
| Q2 2024 | 302 | $534.7M | AMSC, AAPL, MSFT, DRS, NEE |
| Q1 2024 | 306 | $506.7M | MSFT, AAPL, HCI, NEE, CRM |