# Mainline Investment Advisers, LLC

> Mainline Investment Advisers, LLC is an SEC-registered investment advisory firm in Wynnewood, PA, registered since 2011, reporting $100 million to $500 million in regulatory assets under management in its Form ADV filing dated September 1, 2026.

- CRD: 159045
- Filed as: MAINLINE INVESTMENT ADVISERS, LLC
- Also doing business as: MAINLINE COMPANIES, MAINLINE INVESTMENTS
- Registration: SEC-registered investment adviser (status as filed: Approved)
- Location: Wynnewood, PA
- Filing period: October 2026
- Form ADV filing dated: September 1, 2026
- SEC record (IAPD): https://adviserinfo.sec.gov/firm/summary/159045
- AdvisorCensus page: https://advisorcensus.com/firm/mainline-investment-advisers-llc-wynnewood-pa-159045

## Quick answers

**How is Mainline Investment Advisers, LLC compensated?**
On its Form ADV (Item 5.E, October 2026), Mainline Investment Advisers, LLC reports these compensation arrangements: a percentage of assets under its management; fixed fees (other than subscription fees); performance-based fees; other.

**How much does Mainline Investment Advisers, LLC charge?**
Its Form ADV Part 2A brochure dated March 30, 2026 states: Asset-based fee: 0.25% to 2% a year (a range, as the brochure states it). Fees can differ by service and may be negotiable; the brochure is the complete statement.

**Where is Mainline Investment Advisers, LLC located?**
Mainline Investment Advisers, LLC's principal office is in Wynnewood, PA, according to its Form ADV.

**Is Mainline Investment Advisers, LLC registered with the SEC or a state?**
Mainline Investment Advisers, LLC is an SEC-registered investment advisory firm, registered since 2011. Status as filed: Approved. CRD 159045.

**How much does Mainline Investment Advisers, LLC manage?**
Mainline Investment Advisers, LLC reports $109,927,979 in regulatory assets under management in its Form ADV filing dated September 1, 2026 (77% discretionary).

**How have Mainline Investment Advisers, LLC's assets and staff changed since 2021?**
In the Form ADV data for Mainline Investment Advisers, LLC: Regulatory assets under management: $404,993,715 in the October 2021 data and $109,927,979 in the October 2026 data, down 73%. Total employees: 5 in October 2021 and 4 in October 2026. Assets under management move with markets as well as with clients coming and going.

**What types of clients does Mainline Investment Advisers, LLC serve?**
By number of clients on Form ADV Item 5.D: pooled investment vehicles (other than investment companies and business development companies) (9); high net worth individuals (7).

**Does Mainline Investment Advisers, LLC report any disciplinary disclosures?**
Reports no disclosure items on Form ADV Item 11. The detail of any item is on the firm's SEC record: https://adviserinfo.sec.gov/firm/summary/159045

**What changed in Mainline Investment Advisers, LLC's recent Form ADV filings?**
In the April 2026 filing data: Employees performing advisory functions went from 4 to 3. Regulatory assets under management went from $200,838,563 to $109,796,880 (-45%).

## From the Form ADV filing

### Compensation (Item 5.E)
- A percentage of assets under your management
- Fixed fees (other than subscription fees)
- Performance-based fees
- Other

### Fees and minimums (Form ADV Part 2A brochure dated March 30, 2026)

- Asset-based fee: 0.25% to 2% a year (a range, as the brochure states it)

> The Firm charges its clients annual advisory fees that generally range from 0.25% to 2.0% of an asset fee base.

As stated in the firm's brochure. Fees can differ by service and may be negotiable.

### Regulatory assets under management (Item 5.F)
- Total: $109,927,979
- Discretionary: $84,439,443
- Non-discretionary: $25,488,536

### Clients (Item 5.D)

| Client type | Clients | Assets |
| --- | --- | --- |
| High net worth individuals | 7 | $2,000,000 |
| Pooled investment vehicles (other than investment companies and business development companies) | 9 | $107,927,979 |

### Advisory services (Item 5.G)
- Portfolio management for individuals and/or small businesses
- Portfolio management for pooled investment vehicles (other than investment companies)

### Firm details
- Registered since: 2011 (14 years)
- Employees: 4 total, 3 performing advisory functions
- Wrap fee program participation: No
- States registered or notice-filed: DE, FL, PA
- Disclosures (Item 11): Reports no disclosure items on Form ADV Item 11.

### Websites listed on Form ADV (Item 1.I)
- [mainlineco.com](https://mainlineco.com)
- [mainlineinvestmentadvisers.com](https://mainlineinvestmentadvisers.com)
- LinkedIn @MAINLINE-INVESTMENT-ADVISORS

## Assets and staff over time

| Data period | Regulatory assets under management | Employees | Filing dated |
| --- | --- | --- | --- |
| October 2021 | $404,993,715 | 5 | September 28, 2021 |
| October 2022 | $435,072,100 | 5 | March 30, 2022 |
| October 2023 | $296,489,320 | 5 | April 28, 2023 |
| October 2024 | $244,810,132 | 6 | July 19, 2024 |
| October 2025 | $200,838,563 | 5 | April 29, 2025 |
| October 2026 | $109,927,979 | 4 | September 1, 2026 |

Regulatory assets under management: $404,993,715 in the October 2021 data and $109,927,979 in the October 2026 data, down 73%.
Total employees: 5 in October 2021 and 4 in October 2026.

## Changes in the filing (last 12 months)

### April 2026
- Employees performing advisory functions went from 4 to 3.
- Regulatory assets under management went from $200,838,563 to $109,796,880 (-45%).

### December 2025
- Updated its list of owners and control persons (Schedule A).

## Source

Form ADV as filed, October 2026. Values appear as filed. Cite as: AdvisorCensus. Mainline Investment Advisers, LLC (CRD 159045): Form ADV filing data as of October 2026.