Asset manager · New York, NY
Diameter Principal Finance LLC
SEC-registered investment adviser · CRD 328057 · SEC 801-128935
At a glance
Diameter Principal Finance LLC is an SEC-registered investment adviser based in New York, New York, with $3.4 billion in regulatory assets under management as of its Form ADV filed April 29, 2026. Its largest client group by assets is business development companies. By Form ADV it is a asset manager, ranked 828th of 3,218 asset managers and 2,619th of 17,210 SEC-registered advisers by assets.
Main office 212-665-1400diametercap.comLinkedInAs filed on Form ADV
- Regulatory AUM
- $3.4B
- Rank among asset managers
- #828 of 3,218
- Rank among all SEC RIAs
- #2,619 of 17,210
- Rank in New York
- #655 of 2,591
- Clients
- 1
- Accounts
- 1
- Discretionary
- 100% of AUM
- Employees
- 119
- Advisory staff
- 62
- Offices
- 3
Owners and executives on its Form ADV
- Scott K. GoodwinCo-Chief Executive Officer & Co-President
- Jonathan N. LewinsohnCo-Chief Executive Officer & Co-President
- Benjamin D. PasternackCo-Head & Partner
- Joseph A. CarvalhoCo-Head & Partner
- Michael J. CohnGeneral Counsel and Chief Compliance Officer
- Matthew G. GilmartinChief Financial Officer
Custody and brokerage
Custodian
Diameter Principal Finance 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.
Who it serves
| Client type | Clients | Regulatory AUM | Share |
|---|---|---|---|
| Business development companies | 1 | $3.4B | 100% |
Disciplinary disclosures
Diameter Principal Finance LLC reports no disciplinary disclosures in Item 11 of Form ADV. Read the details on the SEC’s adviser search ↗
Services
- Portfolio management for investment companies
How it’s paid
- A percentage of assets under management
- Performance-based fees
Form ADV and brochures on the SEC’s adviser search ↗diametercap.com ↗
AtlasMembers
The full record on Diameter Principal Finance 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, 2 years of filings
- Locked
- Growth over one, three and five years
- Locked
- Rank against 780 peers of its type and size
- Locked
- Owners and executives, with titles and stakes
- 6 namedLocked
- Main office, fax and compliance officer
- Locked
- Filing changes this year, with alerts
- 2Locked
Free while Atlas launches: create a free account and confirm your email. Every figure comes from SEC filings.
Background
Questions
How much does Diameter Principal Finance LLC manage?
Diameter Principal Finance LLC reports $3.4 billion in regulatory assets under management across 1 accounts, 100% of it on a discretionary basis, on its Form ADV filed April 29, 2026.
What kind of firm is Diameter Principal Finance LLC?
Diameter Principal Finance LLC is a asset manager by its Form ADV answers. Most of its assets are managed for funds, institutions or other businesses rather than individuals.
Who are Diameter Principal Finance LLC’s clients?
By assets, its largest client types are business development companies ($3.4 billion, 1 clients).
Does Diameter Principal Finance LLC have any disciplinary history?
Diameter Principal Finance 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 Diameter Principal Finance 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 (2026-04-29), 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 →