Stocks/Funds/CIK 1222765

WATER ISLAND CAPITAL LLC

Quarterly 13F filings · Latest period 2026-03-31 · CIK 1222765
Assets
$711M
+33.8% YoY
Holdings
77
Lifetime alpha vs market
-6.15% annual
Average hold time
0.6 yr
median 0.3 yr

Quarterly history

Cum return +20% vs S&P +52% · α -32% lifetimeAUM $711M · peak $2.2BFlow $-105M (-14%)2016-062017-122019-062020-122022-062023-122025-062026-03
AUM ($B)fundS&P 500(gap = α)/ Flow in/out

Behavior signals (lifetime)

Dip response
-29.13%
trims when stocks drop
when a holding falls −10%+
Middle response
-6.59%
baseline attrition
Rally response
-16.63%
trims into rallies
when a holding rises +10%+

Top positions · 30

Ticker$ value% portYoYHold time
EAElectronic Arts Inc.$51M7.2%+41.7%0.8 yr
JHGJanus Henderson Group pl$47M6.7%+46.4%0.5 yr
WBDWarner Bros. Discovery, $44M6.2%+155.9%0.5 yr
HOLXHologic, Inc.$42M6.0%+22.4%0.5 yr
TXNMTXNM Energy, Inc.$39M5.6%+12.5%4.0 yr
PENPenumbra, Inc.$39M5.5%+22.8%0.3 yr
GTLSChart Industries, Inc.$39M5.5%+43.2%0.8 yr
NSCNorfolk Southern Corpora$38M5.4%+23.6%3.3 yr
MASIMasimo Corporation$35M4.9%+6.8%0.3 yr
WBSWebster Financial Corpor$29M4.1%+38.5%0.3 yr
TPHTri Pointe Homes, Inc.$25M3.5%+46.4%0.3 yr
NSANational Storage Affilia$22M3.1%+3.1%0.3 yr
GLDDGreat Lakes Dredge & Doc$21M3.0%+95.4%0.3 yr
ACLXArcellx, Inc.$21M3.0%0.3 yr
DAWNDay One Biopharmaceutica$20M2.8%+170.4%0.3 yr

Portfolio composition (YoY)

Industry mix
Medical - Devices10.5%+9.3pp$74M
Asset Management9.6%+8.7pp$68M
Biotechnology8.4%+6.6pp$60M
Electronic Gaming & Multimedia7.2%$51M
Banks - Regional6.5%+6.3pp$46M
Entertainment6.2%+3.9pp$44M
Medical - Instruments & Supplies6.0%$42M
Industrial - Machinery5.8%$41M
Regulated Electric5.6%$39M
Railroads5.4%$38M
Country
US91.4%-0.0pp
GB7.1%
IL1.2%
Unknown0.3%-0.6pp
Top 5: 31.6% · Top 10: 57.0% · Top 25: 89.8%

Winners

TickerPrev $PnLYoY %

Losers

TickerPrev $PnLYoY %

Top buys this quarter · 15

PEN Penumbra, Inc.new+$39M
MASI Masimo Corporationnew+$35M
WBS Webster Financial Corporationnew+$29M
TPH Tri Pointe Homes, Inc.new+$25M
NSA National Storage Affiliates Trnew+$22M
GLDD Great Lakes Dredge & Dock Corpnew+$21M
DAWN Day One Biopharmaceuticals, Innew+$20M
STEL Stellar Bancorp, Inc.new+$16M
JHG Janus Henderson Group plc+$14M
EA Electronic Arts Inc.+$14M

Top sells this quarter · 15

EXAS Exact Sciences Corporationexit$36M
TGNA TEGNA Inc.exit$24M
SEE Sealed Air Corporation$21M
CFLT Confluent, Inc.exit$20M
CWAN Clearwater Analytics Holdings,$18M
AL Air Lease Corporation$15M
CSGS CSG Systems International, Inc$10M
FOLD Amicus Therapeutics, Inc.$9M
QRVO Qorvo, Inc.exit$8M
SEMR Semrush Holdings, Inc.$6M

Quarterly history (TTM returns)

PeriodAUM# PosReturn (1yr)SPY (1yr)Alpha (1yr)Flow
2026-03-31$711M77+68.51%+17.59%+50.92%-0.10B
2025-12-31$766M61+64.95%+17.72%+47.23%+0.06B
2025-09-30$647M58+65.28%+17.52%+47.76%+0.00B
2025-06-30$523M45+31.00%+14.94%+16.06%-0.11B
2025-03-31$531M50-2.59%+8.30%-10.90%-0.27B
2024-12-31$768M49-7.41%+24.89%-32.30%-0.23B
2024-09-30$914M56-13.23%+36.04%-49.27%+0.04B
2024-06-30$899M57-15.88%+24.49%-40.38%+0.14B
2024-03-31$859M41-12.91%+29.62%-42.53%-0.08B
2023-12-31$947M37-19.49%+26.18%-45.67%-0.15B
2023-09-30$1.08B64-24.75%+21.57%-46.32%+0.08B
2023-06-30$1.05B57-20.05%+19.42%-39.48%-0.05B
2023-03-31$1.22B55-15.95%-7.82%-8.13%+0.15B
2022-12-31$1.16B66-4.85%+7.56%-12.41%-0.50B
2022-09-30$1.74B73+0.56%-4.93%+5.49%+0.16B
2022-06-30$1.58B70-4.13%-16.11%+11.98%-0.28B