GAGNON SECURITIES LLC

New York, NY · CIK 1125725 · 13F filing filed 2026-08-05

SEC-registered investment adviser since 2005 · limited liability company

Assets managed$529.7m
Staff19 · 10 in investment roles
Main clients (by assets)Individuals 47%, High net worth individuals 42%, Companies 11%
Websitegagnonsec.com
Form ADV · 2026-08-12SEC adviser record

$518.8m reported value +19.8% vs Q1 2026

83positions

47.7%in top 10

4 new 25 added 46 reduced 6 sold out vs Q1 2026

Holdings, Q2 2026

The small lines show how much was held over the last 4 quarters (adjusted for stock splits).

#	Security	Ticker	Shares	Value	% of portfolio	Change	Shares change
1	CAREDX INC COM CDNA	CDNA	1,770,735	$50.5m9.73%	9.73%	Added +8.9k	+8,861 0.5%
2	GENEDX HOLDINGS CORP COM CL A WGS	WGS	524,865	$36.0m6.94%	6.94%	Added +221.7k	+221,716 73.1%
3	ENSIGN GROUP INC COM ENSG	ENSG	173,911	$27.9m5.37%	5.37%	Reduced -5.8k	-5,760 -3.2%
4	AMERESCO INC CL A AMRC	AMRC	826,562	$22.8m4.40%	4.40%	Reduced -13.5k	-13,501 -1.6%
5	GENERAC HLDGS INC COM GNRC	GNRC	73,170	$21.4m4.13%	4.13%	Reduced -1.7k	-1,743 -2.3%
6	ENTERPRISE PRODS PARTNERS L COM EPD	EPD	510,576	$18.8m3.62%	3.62%	Reduced -3.7k	-3,681 -0.7%
7	QUIDELORTHO CORP COM QDEL	QDEL	1,030,371	$18.0m3.48%	3.48%	Added +627.0k	+627,046 155.5%
8	CHEESECAKE FACTORY INC COM CAKE	CAKE	221,792	$17.6m3.40%	3.40%	Reduced -3.3k	-3,256 -1.4%
9	EQUINIX INC COM EQIX	EQIX	16,720	$17.4m3.36%	3.36%	Reduced -231	-231 -1.4%
10	CARMAX INC COM KMX	KMX	325,410	$17.2m3.32%	3.32%	Added +15.7k	+15,711 5.1%
11	FRESHWORKS INC CLASS A COM FRSH	FRSH	1,563,866	$15.8m3.05%	3.05%	Reduced -167.5k	-167,501 -9.7%
12	PACIRA BIOSCIENCES INC COM PCRX	PCRX	608,617	$15.4m2.98%	2.98%	Reduced -8.9k	-8,893 -1.4%
13	FIVE9 INC COM FIVN	FIVN	722,698	$15.4m2.97%	2.97%	Added +100.6k	+100,634 16.2%
14	HINGE HEALTH INC CL A HNGE	HNGE	182,959	$15.2m2.93%	2.93%	Added +58.7k	+58,709 47.2%
15	BIOLIFE SOLUTIONS INC COM NEW BLFS	BLFS	535,906	$15.1m2.92%	2.92%	Reduced -606	-606 -0.1%
16	PROFOUND MED CORP COM NEW PROF	PROF	1,960,074	$13.0m2.51%	2.51%	Added +15.8k	+15,750 0.8%
17	CARGURUS INC COM CL A CARG	CARG	367,073	$12.5m2.41%	2.41%	Added +95.5k	+95,549 35.2%
18	TREACE MED CONCEPTS INC COM TMCI	TMCI	3,029,543	$12.1m2.32%	2.32%	Reduced -2.2m	-2,172,343 -41.8%
19	N/A 0 0		765,179	$11.7m2.25%	2.25%	New
20	INTUITIVE SURGICAL INC COM NEW ISRG	ISRG	29,144	$11.6m2.23%	2.23%	Reduced -2.5k	-2,475 -7.8%
21	BLACKLINE INC COM BL	BL	375,769	$10.5m2.03%	2.03%	Added +79.3k	+79,345 26.8%
22	ASPEN AEROGELS INC COM ASPN	ASPN	1,535,812	$9.7m1.88%	1.88%	Reduced -326.0k	-326,039 -17.5%
23	PROTO LABS INC COM PRLB	PRLB	116,283	$9.5m1.83%	1.83%	Added +5.4k	+5,394 4.9%
24	VERTEX INC CL A VERX	VERX	761,026	$8.7m1.68%	1.68%	Added +292.8k	+292,806 62.5%
25	AMPLITUDE INC COM CL A AMPL	AMPL	1,055,508	$8.1m1.56%	1.56%	Reduced -4.3k	-4,328 -0.4%
26	MARINEMAX INC COM HZO	HZO	211,480	$7.7m1.49%	1.49%	Reduced -9.1k	-9,130 -4.1%
27	ORASURE TECHNOLOGIES INC COM OSUR	OSUR	1,592,147	$7.1m1.37%	1.37%	Reduced -122.2k	-122,244 -7.1%
28	DOUBLEVERIFY HLDGS INC COM DV	DV	523,328	$5.7m1.09%	1.09%	Added +34.9k	+34,866 7.1%
29	CELCUITY INC COM CELC	CELC	53,240	$5.6m1.07%	1.07%	Reduced -102	-102 -0.2%
30	CHIPOTLE MEXICAN GRILL INC COM CMG	CMG	155,463	$5.3m1.02%	1.02%	Reduced -2.4k	-2,386 -1.5%
31	CARETRUST REIT INC COM CTRE	CTRE	129,955	$5.2m1.01%	1.01%	Reduced -3.1k	-3,091 -2.3%
32	PENNANT GROUP INC COM PNTG	PNTG	135,035	$5.0m0.96%	0.96%	Reduced -2.4k	-2,449 -1.8%
33	WHITECAP RESOURCES INC COM NEW WCPRF	WCPRF	435,100	$4.5m0.87%	0.87%	Reduced -318	-318 -0.1%
34	ICU MED INC COM ICUI	ICUI	29,400	$4.3m0.83%	0.83%	Reduced -343	-343 -1.1%
35	KALTURA INC COM KLTR	KLTR	3,266,999	$4.2m0.82%	0.82%	Reduced -11.9k	-11,937 -0.4%
36	MICROCHIP TECHNOLOGY INC. COM MCHP	MCHP	26,229	$2.4m0.46%	0.46%	Reduced -609	-609 -2.3%
37	GENTEX CORP COM GNTX	GNTX	57,159	$1.4m0.28%	0.28%	Added +226	+226 0.4%
38	GLOBAL NET LEASE INC COM NEW GNL	GNL	160,598	$1.4m0.28%	0.28%	Reduced -9.5k	-9,527 -5.6%
39	SL GREEN RLTY CORP COM SLG	SLG	25,862	$1.3m0.26%	0.26%	Unchanged
40	BOSTON BEER INC CL A SAM	SAM	7,283	$1.3m0.25%	0.25%	Added +44	+44 0.6%
41	NCINO INC COM NCNO	NCNO	75,333	$1.2m0.24%	0.24%	Reduced -4.2k	-4,187 -5.3%
42	FLAGSTAR FINANCIAL INC COM NEW FLG	FLG	74,456	$1.1m0.21%	0.21%	Reduced -255	-255 -0.3%
43	DIGITAL TURBINE INC COM NEW APPS	APPS	81,839	$1.1m0.20%	0.20%	Unchanged
44	WEAVE COMMUNICATIONS INC COM WEAV	WEAV	157,170	$998.7k0.19%	0.19%	Added +123.0k	+122,950 359.3%
45	DOCUSIGN INC COM DOCU	DOCU	20,906	$928.6k0.18%	0.18%	Reduced -326	-326 -1.5%
46	CNFINANCE HLDGS LTD SPONSORED ADS CNF	CNF	332,345	$920.6k0.18%	0.18%	Added +18.4k	+18,407 5.9%
47	ALPHABET INC CAP STK CL A GOOGL	GOOGL	2,556	$913.4k0.18%	0.18%	Unchanged
48	MARVELL TECHNOLOGY INC COM MRVL	MRVL	2,923	$870.7k0.17%	0.17%	Reduced -3.9k	-3,902 -57.2%
49	BIO-TECHNE CORP COM TECH	TECH	12,230	$864.0k0.17%	0.17%	Added +2.4k	+2,351 23.8%
50	DEVON ENERGY CORP NEW COM DVN	DVN	19,021	$785.9k0.15%	0.15%	Reduced -45	-45 -0.2%
51	MICRON TECHNOLOGY INC COM MU	MU	679	$783.8k0.15%	0.15%	Reduced -398	-398 -37.0%
52	Nintendo Co Ltd COM NTDOY	NTDOY	70,675	$740.7k0.14%	0.14%	Added +978	+978 1.4%
53	COGNEX CORP COM CGNX	CGNX	9,798	$709.6k0.14%	0.14%	Added +18	+18 0.2%
54	NVIDIA CORPORATION COM NVDA	NVDA	3,498	$699.9k0.13%	0.13%	Reduced -157	-157 -4.3%
55	COMMVAULT SYS INC COM CVLT	CVLT	4,874	$690.8k0.13%	0.13%	Added +498	+498 11.4%
56	ALPHABET INC CAP STK CL C GOOG	GOOG	1,929	$681.6k0.13%	0.13%	Reduced -5	-5 -0.3%
57	ONTO INNOVATION INC COM ONTO	ONTO	1,709	$646.8k0.12%	0.12%	Reduced -533	-533 -23.8%
58	AT&T INC COM T	T	30,898	$639.6k0.12%	0.12%	Reduced -1.2k	-1,196 -3.7%
59	HIMAX TECHNOLOGIES INC SPONSORED ADR HIMX	HIMX	39,498	$605.9k0.12%	0.12%	Reduced -5.3k	-5,275 -11.8%
60	PFIZER INC COM PFE	PFE	23,346	$562.2k0.11%	0.11%	Reduced -20.9k	-20,914 -47.2%
61	LIFE TIME GROUP HOLDINGS INC COMMON STOCK LTH	LTH	13,465	$549.9k0.11%	0.11%	Reduced -85	-85 -0.6%
62	MACOM TECH SOLUTIONS HLDGS I COM MTSI	MTSI	1,281	$487.3k0.09%	0.09%	Reduced -2.4k	-2,389 -65.1%
63	VIAVI SOLUTIONS INC COM VIAV	VIAV	9,986	$476.8k0.09%	0.09%	Reduced -4.5k	-4,525 -31.2%
64	META PLATFORMS INC CL A META	META	839	$472.6k0.09%	0.09%	Unchanged
65	SHOPIFY INC CL A SUB VTG SHS SHOP	SHOP	4,023	$459.3k0.09%	0.09%	Added +91	+91 2.3%
66	ETSY INC COM ETSY	ETSY	5,755	$433.5k0.08%	0.08%	Reduced -18	-18 -0.3%
67	STARBUCKS CORP COM SBUX	SBUX	4,045	$413.4k0.08%	0.08%	Reduced -26	-26 -0.6%
68	MERCK & CO INC COM MRK	MRK	3,187	$409.5k0.08%	0.08%	Reduced -5	-5 -0.2%
69	CES ENERGY SOLUTIONS C F FOREIGN CANADIAN CESDF	CESDF	33,350	$389.5k0.08%	0.08%	Unchanged
70	AKAMAI TECHNOLOGIES INC COM AKAM	AKAM	3,163	$373.9k0.07%	0.07%	Added +267	+267 9.2%
71	WARBY PARKER INC CL A COM WRBY	WRBY	11,381	$345.3k0.07%	0.07%	New
72	RINGCENTRAL INC CL A RNG	RNG	8,517	$332.0k0.06%	0.06%	Added +95	+95 1.1%
73	VERICEL CORP COM VCEL	VCEL	7,303	$324.9k0.06%	0.06%	New
74	BEYOND MEAT INC NOTE 3/1 BYND 0 03.15.27	BYND 0 03.15.27	381,271	$286.0k0.06%	0.06%	New
75	PLANET LABS PBC COM CL A PL	PL	8,352	$276.7k0.05%	0.05%	Unchanged
76	ELECTROVAYA INC COM NEW ELVA	ELVA	26,307	$276.2k0.05%	0.05%	Added +50	+50 0.2%
77	REIN THERAPEUTICS INC COM NEW RNTX	RNTX	229,070	$238.2k0.05%	0.05%	Reduced -10.4k	-10,450 -4.4%
78	RAMBUS INC DEL COM RMBS	RMBS	1,778	$236.0k0.05%	0.05%	Reduced -944	-944 -34.7%
79	BLACKSTONE INC COM BX	BX	1,940	$228.3k0.04%	0.04%	Unchanged
80	MICROSOFT CORP COM MSFT	MSFT	556	$207.4k0.04%	0.04%	Added +11	+11 2.0%
81	ACTINIUM PHARMACEUTICALS INC COM ATNM	ATNM	182,142	$178.5k0.03%	0.03%	Reduced -19.2k	-19,158 -9.5%
82	PATTERSON-UTI ENERGY INC COM PTEN	PTEN	17,420	$159.9k0.03%	0.03%	Reduced -297.2k	-297,226 -94.5%
83	REDHILL BIOPHARMA LTD SPONSORED ADR RDHL	RDHL	88,405	$74.7k0.01%	0.01%	Unchanged

Sold out since Q1 2026

Security	Ticker	Shares held before	Value then
NAVIGATOR HLDGS LTD NVGS	NVGS	886,631	$17.1m886.6k shares
ISHARES TR SGOV	SGOV	92,702	$9.3m92.7k shares
ALPHA & OMEGA SEMICONDUCTOR AOSL	AOSL	167,874	$3.7m167.9k shares
GAMBLING COM GROUP LIMITED GRSD	GRSD	109,697	$425.6k109.7k shares
EOG RES INC EOG	EOG	1,851	$267.6k1.9k shares
SAVERS VALUE VLG INC SVV	SVV	25,148	$187.1k25.1k shares

Stakes above 5%

Companies where this manager has reported owning more than 5% of a class of shares, on Schedule 13D (may seek influence) or 13G (passive): its latest filing for each, from 19 Dec 2024 on.

Company	Ticker	Stake	Change	Schedule	Last filed
PROFOUND MED CORP PROF · 13G · filed 2025-01-23	PROF	11.2%≈ $22.3m		13G	2025-01-23
TREACE MED CONCEPTS INC TMCI · 13G · filed 2026-02-12	TMCI	9.6%≈ $24.4m	+3.3 pts	13G	2026-02-12
POWER SOLUTIONS INTL INC PSIX · 13G · filed 2025-01-23	PSIX	7.3%≈ $65.3m	no change	13G	2025-01-23
CNFINANCE HLDGS LTD 13G · filed 2026-02-12		6.8%	no change	13G	2026-02-12
KALTURA INC KLTR · 13G · filed 2026-08-12	KLTR	5.8%≈ $11.5m	new	13G	2026-08-12
ORASURE TECHNOLOGIES INC OSUR · 13G · filed 2026-04-08	OSUR	5.4%≈ $16.7m	+0.5 pts	13G	2026-04-08
AMERESCO INC AMRC · 13G · filed 2026-08-27	AMRC	5.0%≈ $48.7m	+0.1 pts	13G	2026-08-27