Impax Asset Management, Ltd.
- Regulatory AUM
- $25.8B
- Discretionary
- $24.4B
- Clients
- 686
- Avg AUM / client
- $37.7M
- Accounts
- 686
- Employees
- 165
AUM over time
Annual snapshots from Form ADV filings · as of Dec 22, 2025
Who they serve
| Client type | Clients | AUM | % of AUM |
|---|---|---|---|
| Individuals (non-high net worth) | 33 | $7.1M | 0.03% |
| High net worth individuals | 562 | $218M | 0.85% |
| Investment companies | 4 | $2.2B | 8.69% |
| Pooled investment vehicles (non-investment companies) | 27 | $18.0B | 69.7% |
| Pension and profit sharing plans | 9 | $894M | 3.46% |
| Charitable organizations | 7 | $12.8M | 0.05% |
| State or municipal government entities | 3 | $1.5B | 5.67% |
| Other investment advisers | 11 | $1.6B | 6.07% |
| Corporations and other businesses | 17 | $14.3M | 0.06% |
| Other | 13 | $1.4B | 5.4% |
People (3)
| Name | Role / title | Credentials | With firm since | Ownership |
|---|---|---|---|---|
| Simm, Ian | Director, Chief Executive Officer | Aug 1998 (28y) | Less than 5% | |
| Boese, John, Aquinas | Chief Compliance Officer | Nov 2020 (6y) | Less than 5% | |
| Cockburn, Karen | Director, Chief Financial Officer | Dec 2022 (4y) | Less than 5% |
Entity owners (Schedule A/B)
| Entity | Title / status | Since | Sch. | Ownership |
|---|---|---|---|---|
| Impax Asset Management Group Plc | Parent | Jun 1998 | A | 75% or more |
Undisclosed: 0% – 25% of the firm is not attributable from the filed Schedule A bands.
Roster from the IAPD representatives feed; ownership and acquisition dates from Form ADV Schedule A/B. "Since" is the earliest filed registration or acquisition date.
Documents (1 archived)
| Form | Period | Size | |
|---|---|---|---|
| Form ADV (full filing) | 12/22/2025 | 1.35 MB | View · PDF · Source ↗ |
Archived copies of the firm's regulatory filings, versioned by content hash.
Disciplinary disclosures
No disciplinary events reported on the firm's latest Form ADV filing.
How they charge
- • Percentage of assets under management
- • Performance-based fees
Services
- • Portfolio management for individuals/small businesses
- • Portfolio management for investment companies
- • Portfolio management for pooled investment vehicles
- • Portfolio management for businesses/institutional clients
Custody
Reported custodians
- Bnp Paribas $1.0B (4% of AUM) Dec 2025
- State Street $892M (2% of AUM) Dec 2024
- Hsbc $792M (3% of AUM) Dec 2025
- BNY Mellon $729M (3% of AUM) Dec 2025
- Northern Trust $689M (2% of AUM) Dec 2024
- Citibank $563M (2% of AUM) Dec 2025
- J.P. Morgan $462M (2% of AUM) Dec 2025
Amounts as reported in ADV Item 5.K.(3) (custodians holding 10%+ of SMA assets).
Firm reports it does not have custody of client funds or securities (Item 9.A).
Source
All data on this page comes from this firm's Form ADV filings, reproduced without modification. Latest filing: Dec 22, 2025.
View current Form ADV (SEC/IAPD) ↗