Ardsley Partners is an SEC-registered investment adviser based in Norwalk, CT that reports managing 6 hedge funds on Form ADV. It reports $1.6 billion in regulatory assets under management. Its private funds, of all types, hold $838.0 million in gross assets. Its disclosed U.S. stock holdings returned an estimated +46.6% 2026 YTD through Jun 30 (S&P 500: +9.5%), based on 13F filings. Over a longer period they returned an estimated +126.0% from Q3 2024 to Q2 2026, compared with +37.2% for the S&P 500, based on 13F filings.
- Regulatory assets under management
- $1.6 billionForm ADV Item 5.F
- Gross assets of private funds
- $838.0 millionAll private fund types, Form ADV
- Hedge funds managed
- 66 private funds in total
- Employees
- 11Form ADV Item 5.A
- Registration
- SEC-registered adviserCRD 301116
- Latest Form ADV
- 05/06/2026Disciplinary disclosures: none reported
Estimated 13F portfolio performance
| Quarter | Est. 13F return | S&P 500 |
|---|---|---|
| Q2 2026 | +42.5% | +14.8% |
| Q1 2026 | +2.9% | -4.6% |
| Q4 2025 | +10.7% | +2.4% |
| Q3 2025 | +18.8% | +7.8% |
| Q2 2025 | +28.7% | +10.4% |
| Q1 2025 | -15.2% | -4.5% |
| Q4 2024 | +1.6% | +2.1% |
| Q3 2024 | +5.7% | +5.4% |
Estimate of the firm's disclosed long U.S. stock portfolio from its quarterly 13F filings, holding each quarter-end portfolio to the next quarter-end at prices implied by all 13F filers. It is a price return before dividends and fees, ignores shorts, options, bonds, cash and trading within the quarter, and is not the return of any fund. Disclosures
Largest disclosed holdings
- Sandisk$56.7 million
- Advanced Micro Devices Inc Com$54.0 million
- Sezzle Inc$36.9 million
- Terawulf Inc$23.7 million
- Brightspring Health Services I$22.7 million
- Ebay Inc.$22.3 million
- Sunrun Inc$21.4 million
- Viavi Solutions Inc$18.6 million
- Pure Storage$18.3 million
- Arm Holdings PLC Sponsored ADS$16.6 million
As of 2026-06-30, from 13F filing by Ardsley Advisory Partners LP.
Hedge funds filing Form D (6)
Matched to this firm by the fund names and related persons in each Form D. The list may be incomplete.
Private funds reported on Form ADV (6)
As reported in the adviser's Form ADV filed Jan 30, 2024. Funds also listed from Form D are shown above.
From SEC filings. Firm data comes from the SEC's Form ADV data as of Oct 2, 2026; performance estimates come from Form 13F. AltMountain has not verified this information, and it is not an offer, solicitation or recommendation. Full disclosures