Mainstreet RIA provides financial planning, portfolio management for individuals and small businesses, pension consulting, and educational seminars.
Mainstreet RIA reports 141 clients. They include 124 individual clients, 12 high-net-worth individuals, and 5 pension and profit-sharing plans. Of its assets, 100.0% ($472M across 141 accounts) are managed with discretion. It advised 2 clients without assets under management last fiscal year.
| Client type | Clients | Assets |
|---|---|---|
| Individuals (other than HNW) | 88% | 10% |
| High-net-worth individuals | 9% | 6% |
| Pension and profit-sharing plans | 4% | 84% |
Client breakdown and activity details
| Client type | Clients | Regulatory AUM | AUM share | Avg. per client |
|---|---|---|---|---|
| Individuals (other than HNW) | 124 | $47.2M | 10.0% | $380K |
| High-net-worth individuals | 12 | $28.7M | 6.1% | $2.39M |
| Pension and profit-sharing plans | 5 | $396M | 83.9% | $79.2M |
| Total | 141 | $472M | 100% | $3.35M |
- Clients
- 124
- Regulatory AUM
- $47.2M
- AUM share
- 10.0%
- Avg. per client
- $380K
- Clients
- 12
- Regulatory AUM
- $28.7M
- AUM share
- 6.1%
- Avg. per client
- $2.39M
- Clients
- 5
- Regulatory AUM
- $396M
- AUM share
- 83.9%
- Avg. per client
- $79.2M
Total
- Clients
- 141
- Regulatory AUM
- $472M
- AUM share
- 100%
- Avg. per client
- $3.35M
- Clients outside the U.S.
- 0%
- Clients advised without assets under management last fiscal year
- 2
- Private funds advised
- 0
- Financial planning clients last fiscal year
- 0
Mainstreet RIA is paid through a percentage of assets under management, hourly charges and fixed fees (other than subscription fees); its fees and minimums are set out in its brochures on the SEC website.
Robert Oldham owns 25% to 50% of Mainstreet RIA. The leadership team of Mainstreet RIA includes Chief Compliance Officer Nicholas Oldham. It has 3 employees.
Staff
- 3 employees
- 3 in advisory functions
- 3 state-registered reps
- 1 soliciting firm
- Owns 25% to 50% of Mainstreet RIA LLC
Robert Oldham
Control person · since July 2019
- Owns 25% to 50% of Mainstreet RIA LLC
Richard Counts
Control person · since August 2020
- Owns 25% to 50% of Mainstreet RIA LLC
Nicholas Oldham
Control person · since February 2021
Mainstreet RIA’s regulatory assets grew 1.8× from $258M (May 2021) to $472M (September 2026); clients rose from 86 to 141 and employees fell from 4 to 3.
Figures from each annual filing
| Filed | Regulatory AUM | Clients | StaffEmployees | Offices |
|---|---|---|---|---|
| Sep 2026September 2026 | $472M | 141 | 3 | 1 |
| Jan 2025January 2025 | $392M | 136 | 3 | 1 |
| Jul 2024July 2024 | $375M | 136 | 3 | 1 |
| Jan 2023January 2023 | $274M | 103 | 3 | 1 |
| Jul 2022July 2022 | $287M | 109 | 3 | 1 |
| May 2021May 2021 | $258M | 86 | 4 | 2 |
Besides its headquarters, Mainstreet RIA has 0 offices, with 1 listed address in 1 state.
Missouri · 1 listed address
- 6700 Keaton Corporate Parkway, Suite 102, O'FallonHQ
Contact and registration details
- Legal name
- Mainstreet RIA LLC
- Headquarters
- 6700 Keaton Corporate Parkway, Suite 102, O'Fallon, MO 63368
- Website
- mainstreet-ria.com
- Phone
- 888-801-0325
- @mainstreet-ria-llc
- SEC file
- 801-121454
- Structure
- Missouri LLC
- Fiscal year end
- December
Mainstreet RIA’s named custodians for separately managed accounts are Corebridge Financial ($364M, 83%) and Charles Schwab ($74.6M, 17%). Mainstreet RIA does not have custody of client assets.
- Charles SchwabCharles Schwab & Co., Inc. · San Francisco, CA · $74.6M17%
- Corebridge FinancialCorebridge Financial · Amarillo, TX · $364M83%
At year end, Mainstreet RIA’s separately managed accounts were mostly in funds (82%).
What the accounts hold
- Stocks2%
- Funds82%
- Bonds7%
- Other9%
- Fixed interest accounts9%
How many clients does Mainstreet RIA have?
Mainstreet RIA has 141 clients and manages $472 million for them, as of September 2026. They include 124 individual clients, 12 high-net-worth individuals, and 5 pension and profit-sharing plans.
Source: Form ADV Part 1A, Items 5.D and 5.F, filed 29 September 2026
What services does Mainstreet RIA offer?
Mainstreet RIA provides financial planning, portfolio management for individuals and small businesses, pension consulting, and educational seminars.
Source: Form ADV Part 1A, Item 5.G, from the SEC's 2 October 2026 data file
Which custodians does Mainstreet RIA use?
Mainstreet RIA’s separately managed account assets are held at Corebridge Financial (Amarillo, TX), with $364M and Charles Schwab & Co., Inc. (San Francisco, CA), with $74.6M. Only custodians holding at least a tenth of those assets are named.
Source: Form ADV Part 1A, Schedule D, Section 5.K.(3), filed 29 September 2026
How many financial advisors does Mainstreet RIA have?
Mainstreet RIA has 3 investment adviser representatives registered with state securities authorities, out of 3 employees, and 3 perform investment advisory functions. None are registered representatives of a broker-dealer or 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 Mainstreet RIA invest in?
At the end of its last fiscal year, Mainstreet RIA’s separately managed accounts held 82% registered funds (mutual funds, ETFs, BDCs), 9% other, 7% U.S. government and agency bonds and 2% exchange-traded equities. The 9% other category is described as: Fixed Interest Accounts.
Source: Form ADV Part 1A, Items 5.K.(1) and 7.B, from the SEC's 2 October 2026 data file
Who owns Mainstreet RIA?
Mainstreet RIA’s direct owners are Robert Oldham, Richard Counts and Nicholas Oldham, each holding 50% or less.
Source: Form ADV Part 1A, Schedules A and B, filed 29 September 2026
How does Mainstreet RIA get paid?
Mainstreet RIA 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 Mainstreet RIA?
Mainstreet RIA’s main office is at 6700 Keaton Corporate Parkway, Suite 102, O'Fallon, MO 63368. Its phone number is 888-801-0325. Its website is mainstreet-ria.com.