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ARDSLEY PARTNERS
Legal name: ARDSLEY ADVISORY PARTNERS LP
CRD 301116File 801-114966
APPROVED
Custody
Filing as of May 6, 2026
Feed vintage Oct 1, 2026
Regulatory AUM
$1.64B
Top 25% of cohort (national)
Discretionary AUM
$1.64B
Clients
9
11 accounts
Employees
11
Above cohort median in CT
Identity & registration
ADV Item 1- Organization form
- Limited Partnership
- Firm type
- Registered
- SEC region
- BRO
- Registration date
- Mar 27, 2019
- Principal office
- 105 ROWAYTON AVE., NORWALK, CT, 06853
- Phone
- 203-564-4200
- Website
- http://www.ardsley.com/
Assets & accounts
ADV Item 5F- Total regulatory AUM
- $1.64B
- Discretionary AUM
- $1.64B
- Non-discretionary AUM
- $0
- Discretionary accounts
- 11
- Non-discretionary accounts
- 0
- Total accounts
- 11
- AUM per client
- $181.7M
Clients by type
ADV Item 5D| Client type | Clients | AUM |
|---|---|---|
| Pooled investment vehicles | 9 | $1.43B |
Compensation & activities
ADV Items 5E, 5GCompensation
- Performance-based fees
- A percentage of assets under your management
Advisory activities
- Portfolio management for businesses
- Portfolio management for pooled investment vehicles
Custody
ADV Item 9- Firm Custody Cash
- Yes
- Firm Custody Assets
- Yes
- Firm Custody Clients
- Yes
- Firm Custody Securities
- Yes
- Related Person Custody Cash
- No
- Related Person Custody Assets
- No
- Related Person Custody Clients
- No
- Related Person Custody Securities
- Yes
Disclosure events
ADV Item 11This firm answered no to every Item 11 disclosure question in this filing.
Filed changes
| Date | Field | From | To | Change |
|---|---|---|---|---|
| Aug 17, 2026 | Clients | 11 | 9 | decreased by2 |
| Mar 1, 2026 | Employees | 14 | 11 | decreased by3 |
| Mar 1, 2026 | Clients | 10 | 11 | increased by1 |
| Mar 1, 2026 | AUM | $1,143,814,787 | $1,635,701,621 | increased by$491,886,834 |
| Mar 1, 2026 | Accounts | 10 | 11 | increased by1 |
| May 1, 2025 vs Oct 1, 2022 | Employees | 12 | 14 | increased by2 |
| May 1, 2025 vs Oct 1, 2022 | Disclosures | Yes | No | |
| May 1, 2025 vs Oct 1, 2022 | Clients | 6 | 10 | increased by4 |
| May 1, 2025 vs Oct 1, 2022 | AUM | $851,898,478 | $1,143,814,787 | increased by$291,916,309 |
| May 1, 2025 vs Oct 1, 2022 | Accounts | 6 | 10 | increased by4 |
| Apr 1, 2022 | Clients | 8 | 6 | decreased by2 |
| Apr 1, 2022 | AUM | $1,197,794,786 | $851,898,478 | decreased by$345,896,308 |
| Apr 1, 2022 | Accounts | 8 | 6 | decreased by2 |
| Apr 1, 2021 | Registration | — | APPROVED |
On Form 5500, an adviser usually appears as a plan service provider (Schedule C), not the plan sponsor.
See plans that list “ARDSLEY PARTNERS” as a service provider on 5500mcp →Matched by name only — Form ADV and Form 5500 share no identifier, and names are searched loosely (“ARDSLEY PARTNERS” may also match similarly-named firms). Confirm identity against each filing.
Every value above is reproduced from this firm's Form ADV filing. Fields the firm left blank are shown as “Not reported” rather than filled in from other sources.