Wealth manager, public-company owned · New York, NY
Siebert Advisornxt, LLC.
SEC-registered investment adviser · CRD 288572 · SEC 801-110718
At a glance
Siebert Advisornxt, LLC. is an SEC-registered investment adviser based in New York, New York, with $392 million in regulatory assets under management as of its Form ADV filed September 23, 2026. Its largest client group by assets is individuals, and it reports 973 individual clients. By Form ADV it is a wealth manager (public-company owned), ranked 3,559th of 8,915 wealth managers and 8,900th of 17,210 SEC-registered advisers by assets.
Main office 800-872-0444siebertnxt.comAs filed on Form ADV
- Regulatory AUM
- $392M
- Rank among wealth managers
- #3,559 of 8,915
- Rank among all SEC RIAs
- #8,900 of 17,210
- Rank in New York
- #1,616 of 2,591
- Individual clients
- 973
- High-net-worth clients
- 93
- Accounts
- 973
- Discretionary
- 0% of AUM
- Employees
- 43
- Advisory staff
- 32
- Offices
- 9
Owners and executives on its Form ADV
- Mark P. MalekChief Investment Officer
- Andrew H. ReichChief Financial Officer
- Barbara D. VillellaCCO & Amlco
- Peter J. SosnowskiCeo/chief Operating Officer
Custody and brokerage
Custodian
Siebert Advisornxt, LLC.’s Form ADV lists no custodian for separately managed accounts. Firms report one only when they manage $10 million or more in those accounts.
Broker-dealer
Hybrid RIA
Siebert Advisornxt, LLC. is a hybrid RIA: 43 of its employees are also registered representatives of a broker-dealer. It names an affiliated broker-dealer: Muriel Siebert & Co., LLC.
- Muriel Siebert & Co., LLC ↗CRD 5376
An introducing broker-dealer: its trades clear through National Financial Services (Fidelity), which holds the brokerage accounts. Its annual audited report filed with the SEC, March 2026
Its Form ADV brochure (filed September 2026) names Muriel Siebert & Co. as the broker-dealer its advisers are registered with.
Investment Advisory Representatives ("IARs") may, in their separate capacity, be licensed as registered representatives of Muriel Siebert & Co., LLC an affiliated broker -dealer and/or licensed as insurance agents or brokers.
Who it serves
| Client type | Clients | Regulatory AUM | Share |
|---|---|---|---|
| Individuals | 880 | $209M | 53% |
| High-net-worth individuals | 93 | $183M | 47% |
Disciplinary disclosures
Siebert Advisornxt, LLC. reports no disciplinary disclosures in Item 11 of Form ADV. Read the details on the SEC’s adviser search ↗
Services
- Portfolio management for individuals and small businesses
- Other services
How it’s paid
- A percentage of assets under management
Form ADV and brochures on the SEC’s adviser search ↗siebertnxt.com ↗
AtlasMembers
The full record on Siebert Advisornxt, 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, 8 years of filings
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- Growth over one, three and five years
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- Rank against 6,078 peers of its type and size
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- Owners and executives, with titles and stakes
- 4 namedLocked
- Main office, fax and compliance officer
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- Filing changes this year, with alerts
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Background
Questions
How much does Siebert Advisornxt, LLC. manage?
Siebert Advisornxt, LLC. reports $392 million in regulatory assets under management across 973 accounts, on its Form ADV filed September 23, 2026.
What kind of firm is Siebert Advisornxt, LLC.?
Siebert Advisornxt, LLC. is a wealth manager by its Form ADV answers. At least half of its regulatory assets are managed for individuals and high-net-worth individuals. A public reporting company controls it.
Who are Siebert Advisornxt, LLC.’s clients?
By assets, its largest client types are individuals ($209 million, 880 clients); high-net-worth individuals ($183 million, 93 clients).
Does Siebert Advisornxt, LLC. have any disciplinary history?
Siebert Advisornxt, LLC. reports no disciplinary disclosures in Item 11 of its Form ADV. Check the SEC’s adviser search for the latest record.
Where these numbers come from
Every figure is Siebert Advisornxt, 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 (2026-09-23), 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 →