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WATER ISLAND CAPITAL LLC — 13F Holdings & Portfolio

CIK 1222765 · latest 13F-HR filed 2026-05-15

Backtest portfolio

WATER ISLAND CAPITAL LLC manages $895.6M in 13F-reported U.S. long-equity assets across 98 reported positions as of its 2026-03-31 13F-HR filing. Its largest disclosed positions are EA (5.69%), JHG (5.29%), WBD (4.96%). Quarter over quarter (versus its 2025-12-31 filing) the fund opened 51 new positions, exited 40, added to 12, and trimmed 12.

AUM is the long-equity portion reported on Form 13F-HR. Excludes short positions, cash, foreign holdings, and non-13F assets. For informational purposes only — not investment advice.

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AUM

$895.6M

Long-equity book

Holdings

98

Distinct positions

Period

2026-03-31

Filed 2026-05-15

Q/Q Activity

+51 / −40 / ↑12 / ↓12

vs 2025-12-31

Firm Profile & Key People
Name Title / Status Ownership Type

Top Adds (vs prior quarter)

  • JANUS HENDERSON GROUP PLC$16.6M +53.8%
  • ELECTRONIC ARTS INC$14.0M +37.9%
  • WARNER BROS DISCOVERY INC$11.6M +35.2%
  • HOLOGIC INC$7.5M +21.5%
  • DIGITALBRIDGE GROUP INC$5.8M +40.6%
Show all 12 →

Top Trims

  • SEALED AIR CORP NEW-$20.8M -89.8%
  • CLEARWATER ANALYTICS HLDGS I-$18.5M -87.7%
  • AIR LEASE CORP-$14.4M -75.2%
  • CSG SYS INTL INC-$9.9M -86.0%
  • AMICUS THERAPEUTIC-$8.6M -85.0%
Show all 12 →

New Positions

  • PENUMBRA INC$39.4M
  • MASIMO CORP$34.5M
  • WEBSTER FINL CORP$28.9M
  • TRI POINTE HOMES INC$25.1M
  • NATIONAL STORAGE AFFILIATES$21.7M
Show all 51 →

Exited Positions

  • CyberArk Software Ltd$38.7M
  • Exact Sciences Corp$35.5M
  • Comerica Inc$34.6M
  • Cidara Therapeutics Inc$33.3M
  • Avadel Pharmaceuticals PLC$23.4M
Show all 40 →
All Holdings

Rows tagged Call or Put are options positions, not stock. Per SEC Form 13F-HR, Value shows the notional value of the underlying (shares covered × underlying price), not the option premium. Shares is the number of underlying shares covered (divide by 100 for contract count).

# Issuer Symbol CUSIP Value Weight Shares Type
1 ELECTRONIC ARTS INC EA 285512109 $50.9M 5.69% 249,888 SH
2 JANUS HENDERSON GROUP PLC JHG G4474Y214 $47.4M 5.29% 922,277 SH
3 WARNER BROS DISCOVERY INC WBD 934423104 $44.4M 4.96% 1,617,020 SH
4 HOLOGIC INC HOLX 436440101 $42.3M 4.73% 560,045 SH
5 TXNM ENERGY INC TXNM 69349H107 $39.5M 4.40% 674,867 SH
6 PENUMBRA INC PEN 70975L107 $39.4M 4.40% 120,095 SH
7 CHART INDS INC GTLS 16115Q308 $39.3M 4.38% 189,939 SH
8 NORFOLK SOUTHN CORP NSC 655844108 $38.5M 4.30% 134,051 SH
9 MASIMO CORP MASI 574795100 $34.5M 3.86% 194,197 SH
10 ELECTRONIC ARTS INC Put EA 285512959 $30.5M 3.41% 149,800 SH
11 WEBSTER FINL CORP WBS 947890109 $28.9M 3.22% 415,823 SH
12 WARNER BROS DISCOVERY INC Put — 934423954 $28.8M 3.22% 1,049,500 SH
13 TRI POINTE HOMES INC TPH 87265H109 $25.1M 2.80% 536,367 SH
14 NATIONAL STORAGE AFFILIATES NSA 637870106 $21.7M 2.43% 576,224 SH
15 GREAT LAKES DREDGE & DOCK CO GLDD 390607109 $21.5M 2.40% 1,263,580 SH
16 ARCELLX INC ACLX 03940C100 $21.1M 2.35% 183,409 SH
17 DAY ONE BIOPHARMACEUTICALS I DAWN 23954D109 $20.2M 2.26% 944,247 SH
18 DIGITALBRIDGE GROUP INC DBRG 25401T603 $20.0M 2.24% 1,299,051 SH
19 DAY ONE BIOPHARMACEUTICALS I Put DAWN 23954D959 $18.0M 2.01% 839,700 SH
20 STELLAR BANCORP INC STEL 858927106 $15.8M 1.76% 431,231 SH
21 ENHABIT INC EHAB 29332G102 $13.9M 1.55% 984,611 SH
22 SILICON LABORATORIES INC SLAB 826919102 $12.2M 1.36% 58,417 SH
23 KENVUE INC KVUE 49177J102 $12.1M 1.35% 700,600 SH
24 KENVUE INC Put KVUE 49177J952 $12.1M 1.35% 700,600 SH
25 VERIS RESIDENTIAL INC VRE 554489104 $11.3M 1.26% 597,390 SH
26 PEAKSTONE REALTY TRUST PKST 39818P799 $10.5M 1.17% 503,583 SH
27 TERNS PHARMACEUTICALS INC TERN 880881107 $9.9M 1.11% 188,500 SH
28 TERNS PHARMACEUTICALS INC Put TERN 880881957 $9.9M 1.11% 188,500 SH
29 SILICON LABORATORIES INC Put SLAB 826919952 $9.9M 1.11% 47,600 SH
30 KENNEDY-WILSON HOLDINGS INC KW 489398107 $8.9M 1.00% 825,652 SH
31 ZIM INTEGRATED SHIPPING SERV ZIM M9T951109 $8.7M 0.98% 331,800 SH
32 ZIM INTEGRATED SHIPPING SERV Put ZIM M9T951959 $8.7M 0.98% 331,800 SH
33 TXNM ENERGY INC TXNM 69349HAF4 $8.1M 0.90% 6,000,000 PRN
34 JANUS HENDERSON GROUP PLC Put JHG G4474Y954 $7.9M 0.88% 154,300 SH
35 BANCO SANTANDER SA Call BSBR 05964H905 $7.7M 0.86% 681,700 SH
36 UNIFIRST CORP MASS UNF 904708104 $6.5M 0.72% 25,743 SH
37 CSG SYS INTL INC INTWF 126349AH2 $6.1M 0.68% 5,000,000 PRN
38 AXALTA COATING SYS LTD AXTA G0750C108 $5.7M 0.64% 206,902 SH
39 AXALTA COATING SYS LTD Put AXTA G0750C958 $5.4M 0.60% 195,000 SH
40 RAPID7 INC RPD 753422AF1 $4.9M 0.54% 5,501,530 PRN
41 APELLIS PHARMACEUTICALS INC APLS 03753U106 $4.8M 0.54% 120,500 SH
42 APELLIS PHARMACEUTICALS INC Put APLS 03753U956 $4.8M 0.54% 120,500 SH
43 AIR LEASE CORP AL 00912X302 $4.7M 0.53% 73,131 SH
44 BENTLEY SYS INC BSY 08265TAD1 $4.7M 0.53% 5,000,000 PRN
45 NUTANIX INC NTNX 67059NAK4 $4.5M 0.50% 5,000,000 PRN
46 REDFIN CORP — 75737FAE8 $4.3M 0.48% 4,500,000 PRN
47 HALOZYME THERAPEUTICS INC HALO 40637HAD1 $3.1M 0.35% 3,000,000 PRN
48 AES CORP AES 00130H105 $2.6M 0.29% 185,833 SH
49 VARONIS SYS INC VRNS 922280AD4 $2.6M 0.29% 3,000,000 PRN
50 CLEARWATER ANALYTICS HLDGS I CWAN 185123106 $2.6M 0.29% 109,589 SH
Filing History
Period Filed AUM Holdings Accession
2026-03-31 2026-05-15 $895.6M 98 0001222765-26-000007
2025-12-31 2026-02-17 $927.6M 91 0001222765-26-000003
2025-09-30 2025-11-14 $793.3M 84 0001222765-25-000021