Home / Leaderboard / Sunriver Management LLC
Sunriver Management LLC
Will Cook · Hedge Fund · Long/Short Equity
Sunriver Management LLC is a fundamental equity investment firm founded in 2014 by Will Cook and headquartered in Greenwich, Connecticut. The firm specializes in a long/short equity strategy, primarily focusing on underfollowed mid and small-cap companies with market capitalizations typically below $25 billion. Sunriver employs a rigorous, research-driven approach intended to capitalize on market inefficiencies and dislocations often caused by the short-term focus of other market participants. With a background rooted in high-level fundamental analysis from firms like Ziff Brothers Investments, the team manages capital for a range of sophisticated institutional and private investors with a disciplined, repeatable process focused on long-term capital appreciation.
Simulated Performance
| Metric | Value |
|---|---|
| Total return | +1.6% |
| YTD return | -3.0% |
| Sharpe ratio | -0.92 |
| Win rate | 54% |
| AUM | $0.8B |
| Inception | Oct 1, 2025 |
| Updated | Sep 21, 2026 |
Institution Status
| Field | Value |
|---|---|
| AUM | $0.8B |
| Turnover | Low (<15%) |
| Avg holding | 18 Months |
| Inception | Oct 1, 2025 |
| Website | https://www.sunrivermgmt.com/ |
Current Holdings
Updated on Sep 21, 2026.
| Ticker | Name | Portfolio % | Return |
|---|---|---|---|
| LMT | Lockheed Martin Corporation | 10.2% | -18.4% |
| SYY | Sysco Corporation | 6.9% | -6.2% |
| ARMK | Aramark Holdings | 6.4% | +44.1% |
| VRRM | Verra Mobility Corp | 6.4% | -84.0% |
| RTO | Rentokil Initial PLC | 6.3% | -16.9% |
| WEX | Wex Inc | 6.0% | +18.1% |
| HII | Huntington Ingalls Industries Inc | 5.9% | -3.0% |
| SSNC | SS&C Technologies Holdings Inc | 5.3% | -4.1% |
| PFGC | Performance Food Group Co | 5.3% | -8.8% |
| OPLN | OPENLANE, Inc. | 5.1% | +22.1% |
| BOX | Box Inc | 4.7% | +13.3% |
| TRU | TransUnion | 4.6% | -5.2% |
| SWK | Stanley Black & Decker Inc | 4.6% | +20.6% |
| HURN | Huron Consulting Group Inc | 4.3% | +7.8% |
| NABL | N-Able Inc | 3.4% | -46.7% |
| CBZ | CBIZ Inc | 3.4% | +29.2% |
| IQV | IQVIA Holdings Inc | 3.2% | +32.4% |
| FA | First Advantage Corp | 3.0% | +47.0% |
| LYV | Live Nation Entertainment Inc | 2.7% | +2.7% |
| CDW | CDW Corp | 2.4% | +18.2% |
Recent activity
| Date | Action | Ticker | Weight |
|---|---|---|---|
| Mar 2, 2026 | BUY | PFGC | 5.3% → 5.3% |
| Mar 2, 2026 | SELL | BOX | 4.7% → 4.7% |
| Mar 2, 2026 | SELL | FA | 3.0% → 3.0% |
| Mar 2, 2026 | SELL | CBZ | 3.4% → 3.4% |
| Mar 2, 2026 | BUY | SYY | 6.9% → 6.9% |
Investment Style Analysis
Sunriver Management LLC is widely recognized for employing a Long/Short Equity strategy. As of Sep 21, 2026, the firm oversees approximately $0.8B in assets under management (AUM). The portfolio demonstrates a clear preference for the Specialty Business Services and Aerospace & Defense sectors, reflecting a high-conviction approach to capital allocation.
Recent Market Moves
During the latest rebalancing period ending Mar 2, Sunriver Management LLC made a significant move by increasing exposure to PFGC. This adjustment aligns with the fund's dynamic approach to risk management and capital deployment in current market conditions.
Investment Philosophy
Sunriver Management’s investment philosophy is defined by a fundamental, bottom-up approach and a commitment to a long-term time horizon. The firm seeks out "less well-trafficked" stocks where it can find significant valuation gaps and dislocations. By focusing on the small to mid-cap space and maintaining a concentrated portfolio, Sunriver aims to generate high-conviction returns. The strategy prioritizes playing "offense" during periods of market volatility and uncertainty, viewing such times as opportunities to deploy capital into high-quality assets at attractive prices. Ultimately, the firm seeks to maximize absolute long-term returns and build wealth by partnering with investors who prioritize fundamental value over short-term market fluctuations.
Disclaimer
The content provided on this page, including the simulated portfolio performance, holdings analysis, and AI-generated insights, is for informational and educational purposes only. It does not constitute financial advice, investment recommendations, or an offer to buy or sell any securities. All data is derived from historical SEC 13F filings and other public disclosures, which have a reporting lag. The "Simulated Performance" is a hypothetical reconstruction based on past disclosures and does not represent the actual returns of the institution. Past performance is not indicative of future results. Tritonix.ai is not affiliated with Sunriver Management LLC.
Similar Investment Style
Based on Long/Short Equity.
- Perceptive Advisors LLC — Joseph Edelman · 3M +4.5%
- Glenview Capital Management, LLC — Larry Robbins · 3M +10.8%
- Zweig-DiMenna Associates, Inc. — Joseph DiMenna · 3M +4.2%
- Redmile Group, LLC — Jeremy Green · 3M +3.2%
Frequently asked questions
How is the simulated portfolio for Sunriver Management LLC constructed?
This simulation is powered by Tritonix AI using official SEC filings. We focus on the "Best Ideas" by filtering for only the Top 20 largest holdings and rebalancing them to 100%. The simulation tracks performance starting from Oct 1, 2025. Our AI monitors for updates every Monday to capture major shifts. This concentrated approach highlights the manager's true stock-picking skill and mirrors their actual investment returns.
What is Sunriver Management LLC's largest holding?
As of the latest filing, Sunriver Management LLC's top position is Lockheed Martin Corporation (LMT), representing 10.2% of the portfolio. This reflects a high-conviction bet by the institution.
What is Sunriver Management LLC's historical performance and risk profile?
Our simulation indicates a total return of +1.6% with a win rate of 54%. Notably, the portfolio maintains a Sharpe Ratio of -0.92, suggesting an standard level of risk-adjusted returns compared to the broader market.
What sectors does Sunriver Management LLC primarily invest in?
Sunriver Management LLC has a strong preference for the Specialty Business Services sector, which makes up 19.2% of their disclosed assets. The portfolio also has exposure to Aerospace & Defense, indicating a specific thematic focus.
Is Sunriver Management LLC's portfolio concentrated or diversified?
Sunriver Management LLC runs a moderately concentrated portfolio with 20 disclosed positions. The top 3 holdings alone account for 23.5% of the total portfolio weight, suggesting a strategy that favors broader market exposure.
How has Sunriver Management LLC performed in 2026?
Our AI-simulated model portfolio for Sunriver Management LLC tracks a Year-to-Date (YTD) return of -3.0%. This metric helps investors gauge the institution's effectiveness in the current market environment.
Does Will Cook manage Sunriver Management LLC directly?
Yes, Will Cook serves as the key portfolio manager for Sunriver Management LLC, overseeing the investment strategy and final capital allocation decisions.