Fee-only adviser · Portland, ME
Great Diamond Partners, LLC
Great Diamond Partners, LLC is a fee-only investment adviser registered with the U.S. Securities and Exchange Commission, with its main office in Portland, Maine. On its latest Form ADV, filed September 14, 2026, it reports $804M in regulatory assets under management, 523 individual clients and 7 employees who give investment advice. It reports no commission compensation, is not registered as a broker-dealer and does not act as an insurance agent.
Key facts from Form ADV
| Registration | SEC-registered |
|---|---|
| Firm CRD number | 299598 · SEC file 801-115058 |
| Office | 22 Monument Square Suite 300 Portland, ME 04101 |
| Phone | (207) 274-2500 |
| Website | www.greatdiamondpartners.com |
| Regulatory assets under management | $804M |
| Individual clients | 238 non-high-net-worth, 285 high-net-worth |
| Financial planning clients | 101-250 |
| How it charges | Percentage of assets, Hourly, Fixed fee |
| Services | Financial planning, Portfolio management |
| Employees | 12 |
| Disciplinary disclosures | None reported |
| Latest Form ADV filing | September 14, 2026 |
Source: the firm’s Form ADV Part 1A as published by the SEC’s Investment Adviser Public Disclosure database, data as of November 6, 2026. Figures are self-reported by the firm.
What this means for you
- It offers hourly or fixed-fee arrangements, so you may be able to pay for a plan without handing over your investments.
- It also charges a percentage of assets managed for ongoing investment management.
- Most of its individual clients are high-net-worth, which on Form ADV means they meet the SEC’s qualified-client or qualified-purchaser test: broadly, more than $1 million managed by the adviser or a net worth above $2 million, with the thresholds indexed for inflation.
- It provides financial planning services, not only portfolio management.
- It reports no disciplinary history on Form ADV.
Before you hire any adviser
Read the firm’s Form ADV Part 2 brochure on its SEC record: it sets out fees, minimums, conflicts of interest and who will manage your money. Ask whether the firm acts as a fiduciary for all of your accounts, how it is paid in total, and who holds your assets. Our guide to choosing a financial adviser lists the questions to ask.
Other fee-only advisers in Portland
- R M Davis Inc $8.2B
- Old Port Advisors $783M
- Penobscot Financial Advisors $545M
- Headinvest $892M
- Bigelow Investment Advisors, LLC $555M
- Portland Global Advisors LLC $1.2B
See all 14 fee-only advisers in Portland →
Nearby
- South Portland 2 firms
- Falmouth 3 firms
- Westbrook 2 firms
- Yarmouth 2 firms
- Old Orchard Beach 1 firm
- Freeport 1 firm
- New Gloucester 1 firm
- Brunswick 1 firm
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