Data / Investment advisers / Missouri / Mainstreet RIA LLC
Mainstreet RIA LLC, O'Fallon, MO: $472 million AUM, SEC registered investment adviser
Updated November 7, 2026. Source: the SEC's Form ADV data files for investment advisers.
Mainstreet RIA LLC is an SEC registered investment adviser with its main office in O'Fallon, Missouri and reports $472 million in regulatory assets under management in its Form ADV filed September 29, 2026. Its clients include pension and profit sharing plans, individuals and high net worth individuals. It is paid through a percentage of assets under management, hourly charges and fixed fees.
The request: Watch Mainstreet RIA LLC (CRD number 309150): each new Form ADV amendment, with AUM, clients and private funds. $10 of work on sign-up, no card.
SpecStream is the live web data engine for teams and agents. It reads the SEC's Form ADV files every month, and this page is that reading, keyed on the CRD number. Ask for the advisers you track by state, city, size, client type or private funds, and new registrations and filings arrive in your sheet, CRM, Slack or agent as the SEC publishes them.
- Registration
- SEC registered investment adviser
- CRD number
- 309150
- SEC file number
- 801-121454
- SEC status
- Approved, effective June 8, 2021
- Main office
- 6700 Keaton Corporate Parkway Suite 102, O'Fallon, MO 63368
- Phone
- (888) 801-0325
- Regulatory AUM
- $471,751,580 in the Form ADV filed September 29, 2026
- Discretionary AUM
- $471,751,580
- Accounts
- 141
- Employees
- 3, of which 3 give investment advice
- Form of organization
- Limited Liability Company
- Paid through
- a percentage of assets under management, hourly charges, fixed fees
- Form ADV Item 11 disclosures
- None reported
- Latest Form ADV filing
- September 29, 2026
- SEC record
- Investment Adviser Public Disclosure
Clients
Client types the adviser reports in Form ADV item 5.D, with the AUM it attributes to each.
| Client type | Clients | AUM |
|---|---|---|
| Pension and profit sharing plans | 5 | $395.9 million |
| Individuals (other than high net worth individuals) | 124 | $47.2 million |
| High net worth individuals | 12 | $28.7 million |
AUM in the SEC's monthly files
Each change in the AUM the adviser reported across the monthly SEC files held here, with the first file that shows the new value.
| First in the file of | AUM | Form ADV filed |
|---|---|---|
| October 2, 2026 | $471.8 million | September 29, 2026 |
| March 2, 2026 | $446.4 million | February 12, 2026 |
| December 1, 2025 | $392.2 million | January 15, 2025 |
Other advisers in Missouri
| Adviser | City | AUM | Private funds | Source |
|---|---|---|---|---|
| Agellus Capital, LLC | Clayton | $507.8 million | 6 | adviserinfo.sec.gov |
| Financial & Tax Architects, LLC | St. Louis | $506.2 million | Not listed | adviserinfo.sec.gov |
| Fyra Capital Management | St. Charles | $504.2 million | Not listed | adviserinfo.sec.gov |
| Clark Financial Services Group, Inc. | Chesterfield | $498.7 million | Not listed | adviserinfo.sec.gov |
| MBM Wealth Consultants, LLC | Chesterfield | $476.7 million | Not listed | adviserinfo.sec.gov |
| Hofman Wealth Management | Chesterfield | $464.1 million | Not listed | adviserinfo.sec.gov |
| Truenorth Wealth & Impact, LLC | Joplin | $456.2 million | Not listed | adviserinfo.sec.gov |
| Sarver Vrooman Wealth Advisors LLC | Kansas City | $452.2 million | Not listed | adviserinfo.sec.gov |
Also on SpecStream
- Investment advisers in Missouri
- Advisers with $100 million to $500 million in AUM
- Advisers serving pension and profit sharing plans
- Advisers serving individuals
- Mainstreet RIA LLC on the SEC's adviser search
Public data published by the US Securities and Exchange Commission (US government work). Advisers report these values themselves in Form ADV, and neither the SEC nor the states approve or guarantee them. AUM is regulatory assets under management as the adviser reported it in Form ADV item 5.F, which can differ from the AUM a firm quotes elsewhere. Exempt reporting advisers do not report AUM. Office address, phone and website are the adviser's main office as filed; a firm that files its main office as a private residence shows no street address or phone. An Item 11 disclosure is a reported event, not a finding about the firm today. Details for each firm are on the SEC's Investment Adviser Public Disclosure site. This page uses SEC data and is not endorsed or certified by the SEC. Free to reuse with credit to SpecStream under CC BY 4.0. Spot a wrong value? Write to [email protected] with the link to this page.