Broker-dealer firm · New York, NY
Gagnon Securities, LLC
SEC-registered investment adviser · CRD 103727 · SEC 801-64836
At a glance
Gagnon Securities, LLC is an SEC-registered investment adviser based in New York, New York, with $530 million in regulatory assets under management as of its Form ADV filed August 12, 2026. Its largest client group by assets is individuals, and it reports 1,058 individual clients. By Form ADV it is a broker-dealer firm, ranked 207th of 391 broker-dealer firms and 7,601st of 17,210 SEC-registered advisers by assets.
Main office 212-554-5000gagnonsec.comLinkedInAs filed on Form ADV
- Regulatory AUM
- $530M
- Rank among broker-dealer firms
- #207 of 391
- Rank among all SEC RIAs
- #7,601 of 17,210
- Rank in New York
- #1,447 of 2,591
- Individual clients
- 1,058
- High-net-worth clients
- 33
- Accounts
- 1,202
- Discretionary
- 100% of AUM
- Employees
- 19
- Advisory staff
- 10
- Offices
- 1
Owners and executives on its Form ADV
- Matthew Howard JampoleMember
- Henry Carl BeinsteinMember
- Jonathan Williams RobohmMember
- Lisa Catherine FerranteMember
- Alison O'Brien TranchidaMember
- Willis Gitt TaylorMember
- Marianne D'alessandroMember
- Adrienne Michelle GarofaloMember
- Marianne D'alessandroChief Financial Officer
- Alison O'Brien TranchidaOperations Manager
- Lisa Catherine FerranteChief Compliance Officer
- Lisa Catherine FerranteCrop/rop
Custody and brokerage
Broker-dealer
Hybrid RIA
Gagnon Securities, LLC is a hybrid RIA: 19 of its employees are also registered representatives of a broker-dealer.
Its Form ADV brochure (filed May 2026) names Gagnon Securities as the broker-dealer its advisers are registered with.
Other Material Relationships Maureen Drew is a Senior Partner/Registered Representative of Gagnon Securities, she is a member of Gagnon Advisors LLC.
Who it serves
| Client type | Clients | Regulatory AUM | Share |
|---|---|---|---|
| Individuals | 1,025 | $248M | 47% |
| High-net-worth individuals | 33 | $224M | 42% |
| Corporations or other businesses | 144 | $58M | 11% |
Disciplinary disclosures
Gagnon Securities, LLC answers yes to 3 disclosure items in Item 11 of Form ADV (criminal, regulatory or civil matters involving the firm or its advisory affiliates). Read the details on the SEC’s adviser search ↗
Services
- Portfolio management for individuals and small businesses
How it’s paid
- A percentage of assets under management
- Commissions
Form ADV and brochures on the SEC’s adviser search ↗gagnonsec.com ↗
AtlasMembers
The full record on Gagnon Securities, LLC
Ten years of SEC filings, its owners and contacts, and how it stacks up against its peers. Atlas members see all of it.
- Assets, accounts, clients and staff, ten years of filings
- Locked
- Growth over one, three and five years
- Locked
- Rank against 149 peers of its type and size
- Locked
- Owners and executives, with titles and stakes
- 23 namedLocked
- Main office, fax and compliance officer
- Locked
- Filing changes this year, with alerts
- Locked
Free while Atlas launches: create a free account and confirm your email. Every figure comes from SEC filings.
Background
Questions
How much does Gagnon Securities, LLC manage?
Gagnon Securities, LLC reports $530 million in regulatory assets under management across 1,202 accounts, 100% of it on a discretionary basis, on its Form ADV filed August 12, 2026.
What kind of firm is Gagnon Securities, LLC?
Gagnon Securities, LLC is a broker-dealer firm by its Form ADV answers. The firm is itself registered as a broker-dealer as well as an investment adviser.
Who are Gagnon Securities, LLC’s clients?
By assets, its largest client types are individuals ($248 million, 1,025 clients); high-net-worth individuals ($224 million, 33 clients); corporations or other businesses ($58 million, 144 clients).
Does Gagnon Securities, LLC have any disciplinary history?
Gagnon Securities, LLC answers yes to 3 disclosure items in Item 11 of Form ADV, which covers criminal, regulatory and civil matters involving the firm or its advisory affiliates. The details are on the SEC’s adviser search.
Where these numbers come from
Every figure is Gagnon Securities, LLC’s own answer on its latest Form ADV, from the SEC’s registered-adviser list as of October 1, 2026: regulatory assets and accounts (Item 5.F), clients by type (5.D), employees (5.A and 5.B), compensation (5.E) and services (5.G). Custodians come from Schedule D 5.K(3) of its latest filing (2026-08-12), which lists those holding 10% or more of separately managed account assets and the amount at each. “Hybrid” means some employees are also registered representatives of a broker-dealer (Item 5.B(2)); affiliated broker-dealers are the related persons it lists in Item 7.A and Schedule D. Firm type comes from its own answers: broker-dealer firms are registered broker-dealers themselves (Item 6.A); private fund advisers manage mostly private funds (Item 7.B, 5.D); wealth managers manage at least half their assets for individuals (5.D). Ranks compare it by regulatory assets with every SEC-registered adviser and with firms of its type. Figures are as of the firm’s last annual update, so they can lag recent deals and market moves. Regulatory AUM counts assets the firm continuously supervises and can differ from what a firm markets.
Not an endorsement or a recommendation. Before hiring any adviser, read its Form ADV Part 2A brochure and check its record on the SEC’s adviser search. How to check a financial advisor →