Fee-only adviser · Wynnewood, PA
Mainline Investment Advisers, LLC
Mainline Investment Advisers, LLC is a fee-only investment adviser registered with the U.S. Securities and Exchange Commission, with its main office in Wynnewood, Pennsylvania. On its latest Form ADV, filed September 1, 2026, it reports $110M in regulatory assets under management, 7 individual clients and 3 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 | 159045 · SEC file 801-72761 |
| Office | 308 E. Lancaster Avenue Suite 300 Wynnewood, PA 19096 |
| Phone | (610) 896-3000 |
| Website | www.mainlineco.com |
| Regulatory assets under management | $110M ($84M discretionary) |
| Individual clients | 0 non-high-net-worth, 7 high-net-worth |
| Financial planning clients | Not reported |
| How it charges | Percentage of assets, Fixed fee, Other |
| Services | Portfolio management |
| Employees | 4 |
| Disciplinary disclosures | None reported |
| Latest Form ADV filing | September 1, 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 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.
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