Water Island Capital LLC holds a diversified book of 86 stocks worth $750.1M as of Q1 2026 (disclosed May 15, 2026, a ~45-day 13F lag). This quarter they opened Penumbra Inc and trimmed Air Lease Corp. Their largest long position is Electronic Arts Inc at 7% of the equity book. They also disclosed $137.8M in put options (a bearish bet) and $7.7M in call options (bullish), shown separately below and excluded from the equity book.
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curl -H "Authorization: Bearer YOUR_API_KEY" \ "https://arkolith.com/api/v1/funds/1222765/holdings"
Use Arkolith to show WATER ISLAND CAPITAL LLC's latest holdings, largest changes, and filing provenance.
Top-heavy: diversified book
Share of the disclosed book in its largest positions. A higher top-5 share means a more concentrated, higher-conviction portfolio.
67% mapped to company sectors
Direct operating-company sectors from our SIC-based security master. ETF/fund and unclassified holdings stay visible separately; this is not ETF look-through exposure.
Estimated $ traded · quarter-end prices, no cost basis
Bars show each stock's share of the portfolio. Click a row for its position history.
| # | Security | Value | Shares | % Port | Last move | History |
|---|---|---|---|---|---|---|
| 1 | Electronic Arts Inc Equity | $50.9M | 249.9K | 6.8% | ▲+38% Added · +69K sh | |
| 2 | Janus Henderson Group PLC Equity | $47.4M | 922.3K | 6.3% | ▲+42% Added · +275K sh | |
| 3 | Warner Bros Discovery Inc Equity | $44.4M | 1.62M | 5.9% | ▲+42% Added · +477K sh | |
| 4 | Hologic Inc Equity | $42.3M | 560.0K | 5.6% | ▲+20% Added · +92K sh | |
| 5 | TXNM Energy Inc Equity | $39.5M | 674.9K | 5.3% | ▲+17% Added · +98K sh | |
| 6 | Penumbra Inc Equity | $39.4M | 120.1K | 5.3% | ▲New New position | |
| 7 | Chart Inds Inc Equity | $39.3M | 189.9K | 5.2% | ▲+0.8% Added · +2K sh | |
| 8 | Norfolk Southn Corp Equity | $38.5M | 134.1K | 5.1% | ▲+3.9% Added · +5K sh | |
| 9 | Masimo Corp Equity | $34.5M | 194.2K | 4.6% | ▲New New position | |
| 10 | Webster Finl Corp Equity | $28.9M | 415.8K | 3.8% | ▲New New position | |
| 11 | Tri Pointe Homes Inc Equity | $25.1M | 536.4K | 3.3% | ▲New New position | |
| 12 | National Storage Affiliates Equity | $21.7M | 576.2K | 2.9% | ▲New New position | |
| 13 | Great Lakes Dredge & Dock Co Equity | $21.5M | 1.26M | 2.9% | ▲New New position | |
| 14 | Arcellx Inc Equity | $21.1M | 183.4K | 2.8% | ▲New New position | |
| 15 | Day One Biopharmaceuticals I Equity | $20.2M | 944.2K | 2.7% | ▲New New position | |
| 16 | Digitalbridge Group Inc Equity | $20.0M | 1.30M | 2.7% | ▲+40% Added · +370K sh | |
| 17 | Stellar Bancorp Inc Equity | $15.8M | 431.2K | 2.1% | ▲New New position | |
| 18 | Enhabit Inc Equity | $13.9M | 984.6K | 1.8% | ▲New New position | |
| 19 | Silicon Laboratories Inc Equity | $12.2M | 58.4K | 1.6% | ▲New New position | |
| 20 | Kenvue Inc Equity | $12.1M | 700.6K | 1.6% | ▲+1.5% Added · +10K sh | |
| 21 | Veris Residential Inc Equity | $11.3M | 597.4K | 1.5% | ▲New New position | |
| 22 | Peakstone Realty Trust Equity | $10.5M | 503.6K | 1.4% | ▲New New position | |
| 23 | Terns Pharmaceuticals Inc Equity | $9.9M | 188.5K | 1.3% | ▲New New position | |
| 24 | Kennedy-Wilson Holdings Inc Equity | $8.9M | 825.7K | 1.2% | ▲New New position | |
| 25 | Zim Integrated Shipping Serv Equity | $8.7M | 331.8K | 1.2% | ▲New New position | |
| 26 | TXNM Energy Inc Convertible Bond | $8.1M | 6.00M | 1.1% | ▲+100% Added · +3.0M sh | |
| 27 | Unifirst Corp Mass Equity | $6.5M | 25.7K | 0.9% | ▲New New position | |
| 28 | CSG Sys Intl Inc Convertible Bond | $6.1M | 5.00M | 0.8% | —Held | |
| 29 | Axalta Coating Sys Ltd Equity | $5.7M | 206.9K | 0.8% | ▲+0.6% Added · +1K sh | |
| 30 | Rapid7 Inc Convertible Bond | $4.9M | 5.50M | 0.6% | —Held | |
| 31 | Apellis Pharmaceuticals Inc Equity | $4.8M | 120.5K | 0.6% | ▲New New position | |
| 32 | Air Lease Corp Equity | $4.7M | 73.1K | 0.6% | ▼−75% Reduced · −225K sh | |
| 33 | Bentley Sys Inc Convertible Bond | $4.7M | 5.00M | 0.6% | —Held | |
| 34 | Nutanix Inc Convertible Bond | $4.5M | 5.00M | 0.6% | ▲+43% Added · +1.5M sh | |
| 35 | Redfin Corp Convertible Bond | $4.3M | 4.50M | 0.6% | —Held | |
| 36 | Halozyme Therapeutics Inc Convertible Bond | $3.1M | 3.00M | 0.4% | —Held | |
| 37 | Aes Corp Equity | $2.6M | 185.8K | 0.3% | ▲New New position | |
| 38 | Varonis Sys Inc Convertible Bond | $2.6M | 3.00M | 0.3% | —Held | |
| 39 | Clearwater Analytics Hldgs I Equity | $2.6M | 109.6K | 0.3% | ▼−87% Reduced · −766K sh | |
| 40 | Sealed Air Corp New Equity | $2.4M | 56.1K | 0.3% | ▼−90% Reduced · −503K sh | |
| 41 | Allied Gold Corp Equity | $2.3M | 72.8K | 0.3% | ▲New New position | |
| 42 | Onestream Inc Equity | $2.2M | 91.1K | 0.3% | ▲New New position | |
| 43 | Brighthouse Finl Inc Equity | $2.0M | 33.5K | 0.3% | ▲+16% Added · +5K sh | |
| 44 | NCR Atleos Corporation Equity | $1.7M | 38.9K | 0.2% | ▲New New position | |
| 45 | Select Med Hldgs Corp Equity | $1.7M | 103.5K | 0.2% | ▲New New position | |
| 46 | Thermon Group Hldgs Inc Equity | $1.7M | 33.0K | 0.2% | ▲New New position | |
| 47 | Sun Ctry Airls Hldgs Inc Equity | $1.6M | 98.9K | 0.2% | ▲New New position | |
| 48 | Centessa Pharmaceuticals PLC Equity | $1.6M | 41.0K | 0.2% | ▲New New position | |
| 49 | CSG Sys Intl Inc Equity | $1.6M | 20.2K | 0.2% | ▼−87% Reduced · −130K sh | |
| 50 | Semrush Hldgs Inc Equity | $1.6M | 133.9K | 0.2% | ▼−79% Reduced · −495K sh |
Put / call positions from the 13F — totals include every disclosed option leg
| Type | Underlying | Notional value | Underlying shares |
|---|---|---|---|
| PUT · bearish | ELECTRONIC ARTS INC | $30.5M | 150K |
| PUT · bearish | WARNER BROS DISCOVERY INC | $28.8M | 1.0M |
| PUT · bearish | DAY ONE BIOPHARMACEUTICALS I | $18.0M | 840K |
| PUT · bearish | KENVUE INC | $12.1M | 701K |
| PUT · bearish | TERNS PHARMACEUTICALS INC | $9.9M | 189K |
| PUT · bearish | SILICON LABORATORIES INC | $9.9M | 48K |
| PUT · bearish | ZIM INTEGRATED SHIPPING SERV | $8.7M | 332K |
| PUT · bearish | JANUS HENDERSON GROUP PLC | $7.9M | 154K |
| CALL · bullish | BANCO SANTANDER SA | $7.7M | 682K |
| PUT · bearish | AXALTA COATING SYS LTD | $5.4M | 195K |
| PUT · bearish | APELLIS PHARMACEUTICALS INC | $4.8M | 121K |
| PUT · bearish | CENTESSA PHARMACEUTICALS PLC | $1.6M | 41K |
13F filers disclose option positions at the market value of the underlying the contracts reference, not the premium paid. A put is a bearish bet (it gains if the stock falls); a call is bullish. “Underlying shares” is the share count the contracts control, not a share holding. These legs are excluded from the equity book, weighting, concentration and sector figures above.
As-of date vs the date the SEC received each filing
| Quarter | As of | Filed | Positions | Value | Form |
|---|---|---|---|---|---|
| Q1 2026 | Mar 31, 2026 | May 15, 2026 | 98 | $895.6M | 13F-HR |
| Q4 2025 | Dec 31, 2025 | Feb 17, 2026 | 91 | $927.6M | 13F-HR |
| Q3 2025 | Sep 30, 2025 | Nov 14, 2025 | 84 | $793.3M | 13F-HR |
| Q2 2025 | Jun 30, 2025 | Aug 14, 2025 | 76 | $702.0M | 13F-HR |
| Q1 2025 | Mar 31, 2025 | May 15, 2025 | 84 | $764.1M | 13F-HR |
| Q4 2024 | Dec 31, 2024 | Feb 13, 2025 | 78 | $925.7M | 13F-HR |
| Q2 2024 | Jun 30, 2024 | Nov 14, 2024 | 75 | $986.6M | 13F-HR/A |
| Q1 2024 | Mar 31, 2024 | Nov 14, 2024 | 61 | $961.8M | 13F-HR/A |
| Q4 2023 | Dec 31, 2023 | Nov 14, 2024 | 58 | $1.0B | 13F-HR/A |
Holdings from SEC EDGAR 13F-HR filings, updated quarterly ~45 days after quarter-end. Public domain. The book and weighting are long equity only; disclosed put/call options are listed separately and excluded from those totals. Price-derived performance is withheld until the price-source policy and freshness gate are green.