# EDGAR Filing Document

**Accession Number:** 0001125725
**File Stem:** 0001019056-25-000228
**Filing Date:** 2025-11
**Character Count:** 12192
**Document Hash:** 1581cf7873ebf318eae6f941076edf2e
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0001019056-25-000228.hdr.sgml**: 20251103

**ACCESSION NUMBER**: 0001019056-25-000228

**CONFORMED SUBMISSION TYPE**: 13F-HR

**PUBLIC DOCUMENT COUNT**: 2

**CONFORMED PERIOD OF REPORT**: 20250930

**FILED AS OF DATE**: 20251103

**DATE AS OF CHANGE**: 20251103

**EFFECTIVENESS DATE**: 20251103

**FILER**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** GAGNON SECURITIES LLC
- **CENTRAL INDEX KEY:** 0001125725

**ORGANIZATION NAME:**
- **EIN:** 134087058
- **STATE OF INCORPORATION:** DE
- **FISCAL YEAR END:** 1231

**FILING VALUES:**
- **FORM TYPE:** 13F-HR
- **SEC ACT:** 1934 Act
- **SEC FILE NUMBER:** 028-06377
- **FILM NUMBER:** 251443771

**BUSINESS ADDRESS:**
- **STREET 1:** 1370 AVENUE OF THE AMERICAS
- **STREET 2:** 26TH FLOOR
- **CITY:** NEW YORK
- **STATE:** NY
- **ZIP:** 10019
- **BUSINESS PHONE:** 212-554-5000

**MAIL ADDRESS:**
- **STREET 1:** 1370 AVENUE OF THE AMERICAS
- **STREET 2:** 26TH FLOOR
- **CITY:** NEW YORK
- **STATE:** NY
- **ZIP:** 10019

### FORM 13F COVER PAGE

**Report for the Calendar Year or Quarter Ended:** 09-30-2025

**Check here if Amendment** [ ] **Amendment Number:** 

**This Amendment (Check only one.):** [ ] is a restatement.

[ ] adds new holdings entries.

**Institutional Investment Manager Filing this Report:**

**Name:** GAGNON SECURITIES LLC<br>**Address:** 1370 Avenue of the Americas<br>26th Floor<br>New York, NY 10019

**Form 13F File Number:** 028-06377

**CRD Number (if applicable):** 000103727

**SEC File Number (if applicable):** 801-64836

The institutional investment manager filing this report and the person by whom it is signed hereby represent that the person signing the report is authorized to submit it, that all information contained herein is true, correct and complete, and that it is understood that all required items, statements, schedules, lists, and tables, are considered integral parts of this form.

**Person Signing this Report on Behalf of Reporting Manager:**

**Name:** Lisa Ferrante<br>**Title:** Chief Compliance Officer<br>**Phone:** 212-554-5000

**Signature, Place, and Date of Signing:**

/s/ Lisa Ferrante  New York, NY  11-03-2025<br>[Signature]  [City, State]  [Date]

**Report Type (Check only one.):**

[x] **13F HOLDINGS REPORT.** (Check here if all holdings of this reporting manager are reported in this report.)

[ ] **13F NOTICE.** (Check here if no holdings are reported in this report, and all holdings are reported by other reporting manager(s).)

[ ] **13F COMBINATION REPORT.** (Check here if a portion of the holdings for this reporting manager are reported in this report and a portion are reported by other reporting manager(s).)

### Form 13F Summary Page

**Report Summary:**

**Number of Other Included Managers:** 0

**Form 13F Information Table Entry Total:** 86

**Form 13F Information Table Value Total:** $498503418

      (round to nearest dollar)

**List of Other Included Managers:**

Provide a numbered list of the name(s) and Form 13F file number(s) of all institutional investment managers with respect to which this report is filed, other than the manager filing this report.

[If there are no entries in this list, state “NONE” and omit the column headings and list entries.]

**NONE**

### FORM 13F INFORMATION TABLE

---

|  |  |  |  |  |  |  |  |  |  |  |  |  |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| NAME OF ISSUER | TITLE OF CLASS | CUSIP | FIGI | VALUE (x$1000) | SHRS OR PRN AMT | SH/PRN | PUT/CALL | INVESTMENT DISCRETION | OTHER MANAGER | VOTING AUTHORITY | VOTING AUTHORITY | VOTING AUTHORITY |
| NAME OF ISSUER | TITLE OF CLASS | CUSIP | FIGI | VALUE (x$1000) | SHRS OR PRN AMT | SH/PRN | PUT/CALL | INVESTMENT DISCRETION | OTHER MANAGER | SOLE | SHARED | NONE |
| ACTINIUM PHARMACEUTICALS INC | COM | 00507W206 |  | 362011 | 226257 | SH |  | SOLE |  | 0 | 0 | 226257 |
| AIR LEASE CORP | CL A | 00912X302 |  | 38547567 | 605618 | SH |  | SOLE |  | 0 | 0 | 605618 |
| ALPHA  OMEGA SEMICONDUCTOR LT | SHS | G6331P104 |  | 6021158 | 215349 | SH |  | SOLE |  | 0 | 0 | 215349 |
| ALPHABET INC | CAP STK CL A | 02079K305 |  | 621364 | 2556 | SH |  | SOLE |  | 0 | 0 | 2556 |
| ALPHABET INC | CAP STK CL C | 02079K107 |  | 470539 | 1932 | SH |  | SOLE |  | 0 | 0 | 1932 |
| AMERESCO INC | CL A | 02361E108 |  | 28858954 | 859409 | SH |  | SOLE |  | 0 | 0 | 859409 |
| AMPLITUDE INC | COM CL A | 03213A104 |  | 5475036 | 510731 | SH |  | SOLE |  | 0 | 0 | 510731 |
| ASPEN AEROGELS INC | COM | 04523Y105 |  | 12213638 | 1754833 | SH |  | SOLE |  | 0 | 0 | 1754833 |
| AT INC | COM | 00206R102 |  | 957873 | 33919 | SH |  | SOLE |  | 0 | 0 | 33919 |
| BACKBLAZE INC | COM CL A | 05637B105 |  | 514047 | 55393 | SH |  | SOLE |  | 0 | 0 | 55393 |
| BIOLIFE SOLUTIONS INC | COM NEW | 09062W204 |  | 13667161 | 535757 | SH |  | SOLE |  | 0 | 0 | 535757 |
| Bio-Techne Corp | COM | 09073M104 |  | 534827 | 9614 | SH |  | SOLE |  | 0 | 0 | 9614 |
| BLACKLINE INC | COM | 09239B109 |  | 14810599 | 278919 | SH |  | SOLE |  | 0 | 0 | 278919 |
| BOSTON BEER INC | CL A | 100557107 |  | 4547221 | 21508 | SH |  | SOLE |  | 0 | 0 | 21508 |
| CAREDX INC | COM | 14167L103 |  | 25145846 | 1729425 | SH |  | SOLE |  | 0 | 0 | 1729425 |
| CARETRUST REIT INC | COM | 14174T107 |  | 4705556 | 135685 | SH |  | SOLE |  | 0 | 0 | 135685 |
| CARGURUS INC | COM CL A | 141788109 |  | 10138027 | 272308 | SH |  | SOLE |  | 0 | 0 | 272308 |
| CARMAX INC | COM | 143130102 |  | 10123973 | 225629 | SH |  | SOLE |  | 0 | 0 | 225629 |
| CELCUITY INC | COM | 15102K100 |  | 2665377 | 53955 | SH |  | SOLE |  | 0 | 0 | 53955 |
| CES ENERGY SOLUTIONS CORP | COM | 15713J104 |  | 310942 | 46075 | SH |  | SOLE |  | 0 | 0 | 46075 |
| CHEESECAKE FACTORY INC | COM | 163072101 |  | 12421639 | 227336 | SH |  | SOLE |  | 0 | 0 | 227336 |
| CHIPOTLE MEXICAN GRILL INC | COM | 169656105 |  | 4718280 | 120395 | SH |  | SOLE |  | 0 | 0 | 120395 |
| CNFINANCE HLDGS LTD | SPON ADS | 18979T204 |  | 1329072 | 317201 | SH |  | SOLE |  | 0 | 0 | 317201 |
| Cognex Corp | COM | 192422103 |  | 442672 | 9772 | SH |  | SOLE |  | 0 | 0 | 9772 |
| COMMVAULT SYS INC | COM | 204166102 |  | 456470 | 2418 | SH |  | SOLE |  | 0 | 0 | 2418 |
| DEVON ENERGY CORP | COM | 25179M103 |  | 710947 | 20278 | SH |  | SOLE |  | 0 | 0 | 20278 |
| DIGITAL TURBINE INC | COM NEW | 25400W102 |  | 523770 | 81839 | SH |  | SOLE |  | 0 | 0 | 81839 |
| DOUBLEVERIFY HLDGS INC | COM | 25862V105 |  | 8145406 | 679917 | SH |  | SOLE |  | 0 | 0 | 679917 |
| ENSIGN GROUP INC | COM | 29358P101 |  | 31622093 | 183030 | SH |  | SOLE |  | 0 | 0 | 183030 |
| ENTERPRISE PRODS PARTNERS L P | COM | 293792107 |  | 16534075 | 528752 | SH |  | SOLE |  | 0 | 0 | 528752 |
| EQUINIX INC | COM | 29444U700 |  | 13513240 | 17253 | SH |  | SOLE |  | 0 | 0 | 17253 |
| ETSY INC | COM | 29786A106 |  | 329958 | 4970 | SH |  | SOLE |  | 0 | 0 | 4970 |
| EXACT SCIENCES CORP | COM | 30063P105 |  | 9817272 | 179442 | SH |  | SOLE |  | 0 | 0 | 179442 |
| EXXON MOBIL CORP | COM | 30231G102 |  | 814957 | 7228 | SH |  | SOLE |  | 0 | 0 | 7228 |
| FIVE9 INC | COM | 338307101 |  | 7245553 | 299403 | SH |  | SOLE |  | 0 | 0 | 299403 |
| FLAGSTAR BANK NATIONAL ASSOCIA | COM NEW | 649445400 |  | 865707 | 74953 | SH |  | SOLE |  | 0 | 0 | 74953 |
| FRESHWORKS INC | CLASS A COM | 358054104 |  | 21960678 | 1865818 | SH |  | SOLE |  | 0 | 0 | 1865818 |
| GAMBLING COM GROUP LIMITED | ORDINARY SHARES | G3R239101 |  | 188647 | 23062 | SH |  | SOLE |  | 0 | 0 | 23062 |
| GENEDX HOLDINGS CORP | COM CL A | 81663L200 |  | 28989171 | 269066 | SH |  | SOLE |  | 0 | 0 | 269066 |
| GENERAC HLDGS INC | COM | 368736104 |  | 12983711 | 77561 | SH |  | SOLE |  | 0 | 0 | 77561 |
| GENTEX CORP | COM | 371901109 |  | 1562568 | 55214 | SH |  | SOLE |  | 0 | 0 | 55214 |
| GLOBAL NET LEASE INC | COM NEW | 379378201 |  | 1575513 | 193790 | SH |  | SOLE |  | 0 | 0 | 193790 |
| GOODRX HLDGS INC | COM CL A | 38246G108 |  | 186386 | 44063 | SH |  | SOLE |  | 0 | 0 | 44063 |
| HIMAX TECHNOLOGIES INC | SPONSORED ADR | 43289P106 |  | 481129 | 54488 | SH |  | SOLE |  | 0 | 0 | 54488 |
| ICU MED INC | COM | 44930G107 |  | 3448970 | 28751 | SH |  | SOLE |  | 0 | 0 | 28751 |
| INTUITIVE SURGICAL INC | COM NEW | 46120E602 |  | 19391451 | 43359 | SH |  | SOLE |  | 0 | 0 | 43359 |
| KALTURA INC | COM | 483467106 |  | 4155805 | 2885976 | SH |  | SOLE |  | 0 | 0 | 2885976 |
| LIFE TIME GROUP HOLDINGS INC | COMMON STOCK | 53190C102 |  | 373649 | 13538 | SH |  | SOLE |  | 0 | 0 | 13538 |
| MACOM TECH SOLUTIONS HLDGS INC | COM | 55405Y100 |  | 391148 | 3142 | SH |  | SOLE |  | 0 | 0 | 3142 |
| MarineMax Inc | COM | 567908108 |  | 6619970 | 261349 | SH |  | SOLE |  | 0 | 0 | 261349 |
| MARVELL TECHNOLOGY INC | ORD | 573874104 |  | 531911 | 6327 | SH |  | SOLE |  | 0 | 0 | 6327 |
| MERCK  CO INC | COM | 58933Y105 |  | 338909 | 4038 | SH |  | SOLE |  | 0 | 0 | 4038 |
| META PLATFORMS INC | CL A | 30303M102 |  | 616145 | 839 | SH |  | SOLE |  | 0 | 0 | 839 |
| MICROCHIP TECHNOLOGY INC. | COM | 595017104 |  | 1735558 | 27025 | SH |  | SOLE |  | 0 | 0 | 27025 |
| MICRON TECHNOLOGY INC | COM | 595112103 |  | 491586 | 2938 | SH |  | SOLE |  | 0 | 0 | 2938 |
| MICROSOFT CORP | COM | 594918104 |  | 262083 | 506 | SH |  | SOLE |  | 0 | 0 | 506 |
| NAVIGATOR HLDGS LTD | COM | Y62132108 |  | 13412171 | 865860 | SH |  | SOLE |  | 0 | 0 | 865860 |
| NCINO INC | SPONSORED ADS | 63947X101 |  | 1037174 | 38258 | SH |  | SOLE |  | 0 | 0 | 38258 |
| NINTENDO LTD | COM | 654445303 |  | 1497001 | 70150 | SH |  | SOLE |  | 0 | 0 | 70150 |
| NVIDIA CORPORATION | COM | 67066G104 |  | 3838510 | 20573 | SH |  | SOLE |  | 0 | 0 | 20573 |
| ONTO INNOVATION INC | COM | 683344105 |  | 289711 | 2242 | SH |  | SOLE |  | 0 | 0 | 2242 |
| OraSure Technologies Inc | COM | 68554V108 |  | 5119215 | 1594771 | SH |  | SOLE |  | 0 | 0 | 1594771 |
| PACIRA BIOSCIENCES INC | COM | 695127100 |  | 11589207 | 449717 | SH |  | SOLE |  | 0 | 0 | 449717 |
| PATTERSON-UTI ENERGY INC | COM | 703481101 |  | 1081050 | 208697 | SH |  | SOLE |  | 0 | 0 | 208697 |
| PAYPAL HLDGS INC | COM | 70450Y103 |  | 441322 | 6581 | SH |  | SOLE |  | 0 | 0 | 6581 |
| PENNANT GROUP INC | COM | 70805E109 |  | 3573220 | 141682 | SH |  | SOLE |  | 0 | 0 | 141682 |
| PETMED EXPRESS INC | COM | 716382106 |  | 59841 | 23841 | SH |  | SOLE |  | 0 | 0 | 23841 |
| PFIZER INC | COM NEW | 717081103 |  | 1099717 | 43160 | SH |  | SOLE |  | 0 | 0 | 43160 |
| POWER SOLUTIONS INTL INC | COM | 73933G202 |  | 6361709 | 64770 | SH |  | SOLE |  | 0 | 0 | 64770 |
| PROFOUND MED CORP | COM | 74319B502 |  | 8474566 | 1733040 | SH |  | SOLE |  | 0 | 0 | 1733040 |
| PROTO LABS INC | SPON ADS NEW | 743713109 |  | 5440712 | 108749 | SH |  | SOLE |  | 0 | 0 | 108749 |
| QUIDELORTHO CORP | COM NEW | 219798105 |  | 3607596 | 122499 | SH |  | SOLE |  | 0 | 0 | 122499 |
| RAMBUS INC DEL | COM | 750917106 |  | 282486 | 2711 | SH |  | SOLE |  | 0 | 0 | 2711 |
| REDHILL BIOPHARMA LTD | SPONSORED ADR | 757468301 |  | 38674 | 17822 | SH |  | SOLE |  | 0 | 0 | 17822 |
| REIN THERAPEUTICS INC | COM | 00887A204 |  | 261852 | 228692 | SH |  | SOLE |  | 0 | 0 | 228692 |
| RINGCENTRAL INC | CL A | 76680R206 |  | 230177 | 8122 | SH |  | SOLE |  | 0 | 0 | 8122 |
| SAVERS VALUE VLG INC | COM | 80517M109 |  | 182373 | 13764 | SH |  | SOLE |  | 0 | 0 | 13764 |
| SHOPIFY INC | CL A SUB VTG SHS | 82509L107 |  | 794320 | 5345 | SH |  | SOLE |  | 0 | 0 | 5345 |
| SL GREEN RLTY CORP | COM | 78440X887 |  | 1554223 | 25986 | SH |  | SOLE |  | 0 | 0 | 25986 |
| STARBUCKS CORP | COM | 855244109 |  | 476975 | 5638 | SH |  | SOLE |  | 0 | 0 | 5638 |
| TAPESTRY INC | COM CL A | 876030107 |  | 2428944 | 21453 | SH |  | SOLE |  | 0 | 0 | 21453 |
| TREACE MED CONCEPTS INC | COM | 89455T109 |  | 15152777 | 2258238 | SH |  | SOLE |  | 0 | 0 | 2258238 |
| VERTEX INC | COM | 92538J106 |  | 9387601 | 378685 | SH |  | SOLE |  | 0 | 0 | 378685 |
| VIAVI SOLUTIONS INC | COM | 925550105 |  | 304458 | 23992 | SH |  | SOLE |  | 0 | 0 | 23992 |
| WEAVE COMMUNICATIONS INC | COM | 94724R108 |  | 304227 | 45543 | SH |  | SOLE |  | 0 | 0 | 45543 |
| WHITECAP RES INC | CL A | 96467A200 |  | 3713794 | 486570 | SH |  | SOLE |  | 0 | 0 | 486570 |

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