Institutional Manager · CIK 0000201772
ESSEX INVESTMENT MANAGEMENT CO LLC
BOSTON, MA · File #028-00878
Latest AUM
$655.9M
Positions
306
Top-10 Concentration
33.0%
Filings
9
Portfolio Value Over Time
2024-03
2024-06
2024-09
2024-12
2025-03
2025-06
2025-09
2025-12
Biggest QoQ Changes
Ranked by conviction flow (share change × current price) so mark-to-market moves don't dominate. Price effect column shows how much of the $ change was just the stock moving.
| Action | Issuer | Ticker / CUSIP | Δ Shares | Flow ($) | Price Effect |
|---|---|---|---|---|---|
| NEW | EXZEO GROUP INC | XZO | +291,076 | +$7.1M | $0 |
| EXITED | CLEARPOINT NEURO INC | 18507C103 | -232,458 | -$5.1M | $0 |
| EXITED | ENVIRI CORP | 415864107 | -352,360 | -$4.5M | $0 |
| NEW | WINNEBAGO INDS INC | 974637100 | +109,490 | +$4.4M | $0 |
| EXITED | PENGUIN SOLUTIONS INC | 706915105 | -168,126 | -$4.4M | $0 |
| REDUCE | INSMED INC | INSM | -24,654 | -$4.3M | +$2.6M |
| REDUCE | KRATOS DEFENSE & SEC SOLUTIONS | 50077B207 | -53,861 | -$4.1M | -$3.8M |
| EXITED | SUNOPTA INC | 8676EP108 | -695,206 | -$4.1M | $0 |
| NEW | GENTHERM INC | THRM | +111,037 | +$4.0M | $0 |
| EXITED | ONESPAN INC | 68287N100 | -227,628 | -$3.6M | $0 |
Sector Allocation
Filing History
- 13F HOLDINGS REPORTQ/E Dec 2025306 pos · $655.9M
- 13F HOLDINGS REPORTQ/E Sep 2025299 pos · $653.4M
- 13F HOLDINGS REPORTQ/E Jun 2025298 pos · $550.0M
- 13F HOLDINGS REPORTQ/E Mar 2025303 pos · $479.4M
- 13F HOLDINGS REPORTQ/E Dec 2024307 pos · $556.1M
- 13F HOLDINGS REPORTQ/E Sep 2024302 pos · $573.7M
- 13F HOLDINGS REPORTQ/E Jun 2024302 pos · $534.7M
- 13F HOLDINGS REPORTQ/E Mar 2024306 pos · $506.7M
- 13F HOLDINGS REPORTQ/E Dec 2023356 pos · $612.7M
Top 20 Holdings — Dec 2025
| # | Issuer | Ticker | Shares | Value | % of Portfolio |
|---|---|---|---|---|---|
| 1 | TOWER SEMICONDUCTOR LTD | TSEM | 192,628 | $22.6M | 6.00% |
| 2 | KRATOS DEFENSE & SEC SOLUTIONS | 50077B207 | 190,194 | $14.4M | 3.83% |
| 3 | STERLING INFRASTRUCTURE INC | STRL | 44,685 | $13.7M | 3.63% |
| 4 | HCI GROUP INC | HCIIP | 59,209 | $11.3M | 3.01% |
| 5 | LIGAND PHARMACEUTICALS INC | LGNZZ | 60,020 | $11.3M | 3.01% |
| 6 | INSMED INC | INSM | 62,423 | $10.9M | 2.88% |
| 7 | KINIKSA PHARMACEUTICALS INTL P | G52694109 | 250,975 | $10.4M | 2.75% |
| 8 | GLOBALSTAR INC | GSAT | 167,389 | $10.2M | 2.71% |
| 9 | ADAPTIVE BIOTECHNOLOGIES CORP | ADTI | 624,217 | $10.1M | 2.69% |
| 10 | APPLE INC | AAPL | 34,868 | $9.5M | 2.52% |
| 11 | LINCOLN EDL SVCS CORP | 533535100 | 388,819 | $9.4M | 2.49% |
| 12 | CECO ENVIRONMENTAL CORP | CECO | 154,457 | $9.2M | 2.45% |
| 13 | GRAHAM CORP | GHM | 140,691 | $9.0M | 2.40% |
| 14 | MIRUM PHARMACEUTICALS INC | MIRM | 111,310 | $8.8M | 2.33% |
| 15 | LEONARDO DRS INC | DRS | 256,862 | $8.8M | 2.32% |
| 16 | ARGAN INC | AGX | 27,628 | $8.7M | 2.30% |
| 17 | MICROSOFT CORP | MSFT | 17,613 | $8.5M | 2.26% |
| 18 | WILLDAN GROUP INC | WLDN | 76,921 | $8.0M | 2.12% |
| 19 | GOLDMAN SACHS GROUP INC | GSCE | 8,659 | $7.6M | 2.02% |
| 20 | TETRA TECHNOLOGIES INC DEL | 88162F105 | 760,393 | $7.1M | 1.89% |