Booster provides financial planning, portfolio management for individuals and small businesses, pension consulting, selecting other managers, and educational seminars. Financial planning was provided to 1–10 clients last fiscal year.
Booster reports 190 clients. They include 147 individual clients, 29 pension and profit-sharing plans, and 14 high-net-worth individuals. Of its assets, 3.9% ($8.84M across 98 accounts) are managed with discretion; $220M across 128 accounts are not. It advised 4 clients without assets under management last fiscal year.
| Client type | Clients | Assets |
|---|---|---|
| Individuals (other than HNW) | 77% | 17% |
| High-net-worth individuals | 7% | 13% |
| Pension and profit-sharing plans | 15% | 70% |
Client breakdown and activity details
| Client type | Clients | Regulatory AUM | AUM share | Avg. per client |
|---|---|---|---|---|
| Individuals (other than HNW) | 147 | $39.3M | 17.1% | $267K |
| High-net-worth individuals | 14 | $29.5M | 12.9% | $2.11M |
| Pension and profit-sharing plans | 29 | $161M | 70.0% | $5.53M |
| Total | 190 | $229M | 100% | $1.21M |
- Clients
- 147
- Regulatory AUM
- $39.3M
- AUM share
- 17.1%
- Avg. per client
- $267K
- Clients
- 14
- Regulatory AUM
- $29.5M
- AUM share
- 12.9%
- Avg. per client
- $2.11M
- Clients
- 29
- Regulatory AUM
- $161M
- AUM share
- 70.0%
- Avg. per client
- $5.53M
Total
- Clients
- 190
- Regulatory AUM
- $229M
- AUM share
- 100%
- Avg. per client
- $1.21M
- Clients outside the U.S.
- 0%
- Clients advised without assets under management last fiscal year
- 4
- Private funds advised
- 0
- Financial planning clients last fiscal year
- 1–10
Booster is paid through a percentage of assets under management and fixed fees (other than subscription fees); its fees and minimums are set out in its brochures on the SEC website.
Mary Ceselsky-Grunder owns 75% or more of Booster. The leadership team of Booster includes Chief Compliance Officer Mary Ceselsky-Grunder. It has 4 employees, 2 of them in advisory roles.
Leadership
- Mary Ceselsky-GrunderOwner and Chief Compliance Officer
Investment adviser representatives
2 representatives listed in the SEC register as of 9 October 2026.
- Mary Carol Ceselsky-Grunder
- Thomas Clyde Tavenner
Staff
- 4 employees
- 2 in advisory functions
- 2 state-registered reps
- 1 insurance agent
- Owns 75% or more of Booster, LLC
Mary Ceselsky-Grunder
Control person · since April 2021
Booster’s regulatory assets grew from $173M (January 2022) to $229M (March 2026); clients rose from 104 to 190 and employees from 3 to 4.
Figures from each annual filing
| Filed | Regulatory AUM | Clients | Employees | Offices |
|---|---|---|---|---|
| March 2026 | $229M | 190 | 4 | 3 |
| June 2025 | $240M | 249 | 4 | 3 |
| January 2024 | $200M | 255 | 3 | 3 |
| March 2023 | $167M | 207 | 3 | 3 |
| January 2022 | $173M | 104 | 3 | 2 |
Besides its headquarters, Booster has 2 offices (2 private residences, listed without an address), with 1 listed address in Maryland.
Maryland · 1 listed address
- 6 East Eager Street, BaltimoreHQ
Contact and registration details
- Legal name
- Booster, LLC
- Headquarters
- 6 East Eager Street, Baltimore, MD 21202
- Website
- booster401k.com
- Phone
- 410-216-1551
- @booster-401k
- SEC file
- 801-123233
- Structure
- Maryland LLC
- Fiscal year end
- December
Booster uses Ascensus Financial Services ($132M) as custodian for its separately managed accounts. Booster does not have custody of client assets.
- Ascensus Financial ServicesAscensus Financial Services, LLC. · Dresher, PA · $132M100%
At year end, Booster’s separately managed accounts were mostly in funds (75%) and stocks (14%).
What the accounts hold
- Stocks14%
- Funds75%
- Bonds9%
- U.S. government and agency bonds8%
- State and local bonds1%
- Cash2%
How many clients does Booster have?
Booster has 190 clients and manages $229 million for them, as of March 2026. They include 147 individual clients, 29 pension and profit-sharing plans, and 14 high-net-worth individuals.
Source: Form ADV Part 1A, Items 5.D and 5.F, filed 4 March 2026
What services does Booster offer?
Booster provides financial planning, portfolio management for individuals and small businesses, pension consulting, selecting other managers, and educational seminars.
Source: Form ADV Part 1A, Item 5.G, from the SEC's 2 October 2026 data file
Which custodians does Booster use?
Booster’s separately managed account assets are held at Ascensus Financial Services, LLC. (Dresher, PA), with $132M. Only custodians holding at least a tenth of those assets are named.
Source: Form ADV Part 1A, Schedule D, Section 5.K.(3), filed 4 March 2026
How many financial advisors does Booster have?
Booster has 2 investment adviser representatives registered with state securities authorities, out of 4 employees, and 2 perform investment advisory functions. 0 employees are registered representatives of a broker-dealer and 1 employee is a licensed insurance agent.
Source: Form ADV Part 1A, Items 5.A and 5.B, from the SEC's 2 October 2026 data file
What does Booster invest in?
At the end of its last fiscal year, Booster’s separately managed accounts held 75% registered funds (mutual funds, ETFs, BDCs), 14% exchange-traded equities, 8% U.S. government and agency bonds, 2% cash and equivalents and 1% state and local bonds.
Source: Form ADV Part 1A, Items 5.K.(1) and 7.B, from the SEC's 2 October 2026 data file
Who owns Booster?
Booster’s direct owner is Mary Ceselsky-Grunder (75% or more).
Source: Form ADV Part 1A, Schedules A and B, filed 4 March 2026
How does Booster get paid?
Booster is paid through a percentage of assets under management 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 Booster?
Booster’s main office is at 6 East Eager Street, Baltimore, MD 21202. Its phone number is 410-216-1551. Its website is booster401k.com.