Great Diamond Partners provides financial planning, portfolio management for individuals and small businesses, business succession planning, estate planning, and insurance. Financial planning was provided to 101–250 clients last fiscal year.
Great Diamond Partners reports 533 clients. They include 285 high-net-worth individuals, 238 individual clients, and 7 pension and profit-sharing plans. Of its assets, 100.0% ($804M across 1,736 accounts) are managed with discretion. It advised 1 client without assets under management last fiscal year.
| Client type | Clients | Assets |
|---|---|---|
| Individuals (other than HNW) | 45% | 9% |
| High-net-worth individuals | 53% | 89% |
| Pension and profit-sharing plans | 1% | 1% |
| Charitable organizations | <1% | <1% |
Client breakdown and activity details
| Client type | Clients | Regulatory AUM | AUM share | Avg. per client |
|---|---|---|---|---|
| Individuals (other than HNW) | 238 | $73.8M | 9.2% | $310K |
| High-net-worth individuals | 285 | $716M | 89.0% | $2.51M |
| Pension and profit-sharing plans | 7 | $11.8M | 1.5% | $1.69M |
| Charitable organizations | 3 | $2.47M | 0.3% | $824K |
| Total | 533 | $804M | 100% | $1.51M |
- Clients
- 238
- Regulatory AUM
- $73.8M
- AUM share
- 9.2%
- Avg. per client
- $310K
- Clients
- 285
- Regulatory AUM
- $716M
- AUM share
- 89.0%
- Avg. per client
- $2.51M
- Clients
- 7
- Regulatory AUM
- $11.8M
- AUM share
- 1.5%
- Avg. per client
- $1.69M
- Clients
- 3
- Regulatory AUM
- $2.47M
- AUM share
- 0.3%
- Avg. per client
- $824K
Total
- Clients
- 533
- Regulatory AUM
- $804M
- AUM share
- 100%
- Avg. per client
- $1.51M
- Clients outside the U.S.
- 0%
- Clients advised without assets under management last fiscal year
- 1
- Private funds advised
- 0
- Financial planning clients last fiscal year
- 101–250
Great Diamond Partners charges 0.50%–1.20% a year for its Portfolio management services. The fee is billed in advance, is negotiable and has a $5,000 annual minimum. The brochure also prices one other service, listed under fee details.
Fee details and sources
Other fees
- Financial planning
- Financial planning is billed at an hourly fee of $300 or an annual flat fee not to exceed $25,000, negotiable.
Joseph Powers owns 25% to 50% of Great Diamond Partners. The leadership team of Great Diamond Partners includes Chief Financial Officer Helen Andreoli and Chief Compliance Officer John Piper. It has 12 employees, 7 of them in advisory roles.
Staff
- 12 employees
- 7 in advisory functions
- 8 state-registered reps
- 5 insurance agents
- Owns 25% to 50% of Great Diamond Partners, LLC
Joseph Powers
Control person · since May 2019
- Owns 25% to 50% of Great Diamond Partners, LLC
Helen Andreoli
Control person · since April 2026
- Owns 10% to 25% of Great Diamond Partners, LLC
John Piper
Control person · since April 2026
Great Diamond Partners’ regulatory assets grew from $551M (April 2021) to $804M (September 2026); clients rose from 277 to 533 and employees from 8 to 12. In 2025, HeadInvest joined it.
Figures from each annual filing
| Filed | Regulatory AUM | Clients | StaffEmployees | Offices |
|---|---|---|---|---|
| Sep 2026September 2026 | $804M | 533 | 12 | 2 |
| May 2025May 2025 | $613M | 328 | 10 | 1 |
| Mar 2024March 2024 | $649M | 335 | 8 | 1 |
| Apr 2023April 2023 | $541M | 314 | 9 | 1 |
| Mar 2022March 2022 | $671M | 290 | 10 | 1 |
| Apr 2021April 2021 | $551M | 277 | 8 | 1 |
Firms that joined
20251 joined
- HeadInvestTeamNo filed AUM
Firms whose SEC withdrawal reports a sale to this firm, and deals reported in the press. Teams that moved without selling a registered firm may not appear.
Besides its headquarters, Great Diamond Partners has 1 office (1 private residence, listed without an address), with 1 listed address in 1 state.
Maine · 1 listed address
- 22 Monument Square, Suite 300, PortlandHQ
Contact and registration details
- Legal name
- Great Diamond Partners, LLC
- Headquarters
- 22 Monument Square, Suite 300, Portland, ME 04101
- Website
- greatdiamondpartners.com
- Phone
- 207-274-2500
- @great-diamond-partners
- SEC file
- 801-115058
- Founded
- 2019
- Structure
- Delaware LLC
- Fiscal year end
- December
Great Diamond Partners’ named custodian for separately managed accounts is Charles Schwab ($159M). Great Diamond Partners has custody of $187M for 270 clients.
- Charles SchwabCharles Schwab & Co., Inc. · Westlake, TX · $159M100%
At year end, Great Diamond Partners’ separately managed accounts were largely in stocks (42%) and funds (34%). Its reported 13F holdings for the quarter ended 30 June 2026 total $582M across 238 positions; the largest are Vanguard Index Fds (5.6%), iShares TR (5.3%) and iShares TR (4.7%).
What the accounts hold
- Stocks42%
- Funds34%
- Bonds16%
- Investment grade corporate bonds8%
- State and local bonds6%
- U.S. government and agency bonds2%
- Cash8%
How many clients does Great Diamond Partners have?
Great Diamond Partners has 533 clients and manages $804 million for them, as of September 2026. They include 285 high-net-worth individuals, 238 individual clients, and 7 pension and profit-sharing plans.
Source: Form ADV Part 1A, Items 5.D and 5.F, filed 14 September 2026
What services does Great Diamond Partners offer?
Great Diamond Partners provides financial planning, portfolio management for individuals and small businesses, business succession planning, estate planning, and insurance.
Source: Form ADV Part 1A, Item 5.G, from the SEC's 2 October 2026 data file; Part 2A brochure, Item 4
How much does Great Diamond Partners charge?
Great Diamond Partners charges 0.50%–1.20% a year for its Portfolio management services. The fee is billed in advance, is negotiable and has a $5,000 annual minimum.
Which custodians does Great Diamond Partners use?
Great Diamond Partners’ separately managed account assets are held at Charles Schwab & Co., Inc. (Westlake, TX), with $159M. Only custodians holding at least a tenth of those assets are named.
Source: Form ADV Part 1A, Schedule D, Section 5.K.(3), filed 14 September 2026
How many financial advisors does Great Diamond Partners have?
Great Diamond Partners has 8 investment adviser representatives registered with state securities authorities, out of 12 employees, and 7 perform investment advisory functions. 0 employees are registered representatives of a broker-dealer and 5 employees are licensed insurance agents.
Source: Form ADV Part 1A, Items 5.A and 5.B, from the SEC's 2 October 2026 data file
What does Great Diamond Partners invest in?
At the end of its last fiscal year, Great Diamond Partners’ separately managed accounts held 42% exchange-traded equities, 34% registered funds (mutual funds, ETFs, BDCs), 8% investment grade corporate bonds, 8% cash and equivalents, 6% state and local bonds and 2% U.S. government and agency bonds.
Source: Form ADV Part 1A, Items 5.K.(1) and 7.B, from the SEC's 2 October 2026 data file
Who owns Great Diamond Partners?
Great Diamond Partners’ direct owners are John Piper, Joseph Powers and Helen Andreoli, each holding 50% or less.
Source: Form ADV Part 1A, Schedules A and B, filed 14 September 2026
How does Great Diamond Partners get paid?
Great Diamond Partners is paid through a percentage of assets under management, hourly charges and fixed fees. Its Form ADV lists no commissions or performance-based fees among how it is paid.
Source: Form ADV Part 1A, Item 5.E, from the SEC's 2 October 2026 data file
How do I contact Great Diamond Partners?
Great Diamond Partners’ main office is at 22 Monument Square, Suite 300, Portland, ME 04101. Its phone number is 207-274-2500. Its website is greatdiamondpartners.com.