Main Street Research Llc
- Regulatory AUM
- $2.7B
- Discretionary
- $2.7B
- Clients
- 1,031
- Avg AUM / client
- $2.6M
- Accounts
- 3,017
- Employees
- 24
AUM over time
Annual snapshots from Form ADV filings · as of Apr 27, 2026
Who they serve
| Client type | Clients | AUM | % of AUM |
|---|---|---|---|
| Individuals (non-high net worth) | 203 | $67.9M | 2.53% |
| High net worth individuals | 815 | $2.6B | 95.2% |
| Pension and profit sharing plans | 8 | $16.9M | 0.63% |
| Charitable organizations | 5 | $43.9M | 1.64% |
Retirement plan clients
Plans that reported this firm as an investment service provider on Form 5500 Schedule C.
| Plan | Location | Plan year |
|---|---|---|
| Nossaman Llp Profit Sharing & Retirement Savings Plan Ii Nossaman Llp | 2024 | |
| Schwabplan Retirement Savings And Investment Plan The Charles Schwab Corporation | 2024 | |
| Latham & Watkins 401(k) Savings And Profit Sharing Plan Latham & Watkins Llp | 2024 | |
| United Airlines Pilot Retirement Account Plan United Airlines, Inc. | 2024 |
People (17)
roster as of Jul 20, 2026| Name | Role / title | Credentials | With firm since | Ownership |
|---|---|---|---|---|
| James Edmund Demmert | Managing Partner And Chief Investment Officer | Apr 2000 (26y) | 75% or more | |
| Aaron Michael Stern | Managing Partner West, Portfolio Manager | Nov 2014 (12y) | 5% – 10% | |
| Benjamin B Armellini | Managing Partner East, Portfolio Manager | Dec 2015 (11y) | Less than 5% | |
| Natalie Elaine Mc Mahon | Partner And Chief Operating Officer | CFP | Jan 2020 (7y) | Less than 5% |
| Stephanie Hawk Andersen | Registered representative | Jun 2016 (10y) | ||
| Elizabeth Irene Baldassari | Registered representative | Jun 2019 (7y) | ||
| Lily Nicole Taft | Registered representative | CFA | Dec 2019 (7y) | |
| Jacob Adam Swartz | Registered representative | Jun 2021 (5y) | ||
| Jacob Lionel Margo | Registered representative | Oct 2021 (5y) | ||
| Peter A Fiorita | Registered representative | CFP | Oct 2021 (5y) | |
| Roman Tyler Le Febure | Registered representative | Dec 2021 (5y) | ||
| Henrique Cataldi | Registered representative | Apr 2022 (4y) | ||
| Matthew Craig Northrop | Registered representative | CFP | Jan 2024 (3y) | |
| Michael John Sondag | Registered representative | May 2024 (2y) | ||
| Alexandra Mary Rooney | Registered representative | CFP | Jul 2024 (2y) | |
| Janelle Durbin | Registered representative | Sep 2024 (2y) | ||
| Emily Slama | Registered representative | May 2025 (1y) |
Undisclosed: 0% – 20% of the firm is not attributable from the filed Schedule A bands.
Roster from the IAPD representatives feed; ownership and acquisition dates from Form ADV Schedule A/B. "Since" is the earliest filed registration or acquisition date.
Retirement plans served (4)
| Plan | Sponsor | Participants | Plan assets | As of |
|---|---|---|---|---|
| Nossaman Llp Profit Sharing & Retirement Savings Plan Ii | Nossaman Llp | 81 | $66.7M | 01/01/2024 |
| Schwabplan Retirement Savings And Investment Plan | The Charles Schwab Corporation | 32,145 | $8.9B | 01/01/2024 |
| Latham & Watkins 401(k) Savings And Profit Sharing Plan | Latham & Watkins Llp | 4,864 | $3.1B | 01/01/2024 |
| United Airlines Pilot Retirement Account Plan | United Airlines, Inc. | 17,444 | $16.8B | 01/01/2024 |
From Form 5500 service-provider disclosures.
Documents (1 archived)
| Form | Period | Size | |
|---|---|---|---|
| Form ADV (full filing) | 04/27/2026 | 1.01 MB | View · PDF · Source ↗ |
Archived copies of the firm's regulatory filings, versioned by content hash.
Disciplinary disclosures
No disciplinary events reported on the firm's latest Form ADV filing.
How they charge
- • Percentage of assets under management
- • Performance-based fees
Services
- • Financial planning services
- • Portfolio management for individuals/small businesses
- • Portfolio management for businesses/institutional clients
- • Educational seminars/workshops
- • Other services
Custody
Reported custodians
- Charles Schwab & Co. $2.7B (99% of AUM) Apr 2026
Amounts as reported in ADV Item 5.K.(3) (custodians holding 10%+ of SMA assets).
Firm reports having custody of client funds or securities (Item 9.A).
Source
All data on this page comes from this firm's Form ADV filings, reproduced without modification. Latest filing: Apr 27, 2026.
View current Form ADV (SEC/IAPD) ↗