account_balance
Investment manager · 13F filer · SEC CIK 1222765
Water Island Capital LLC
Reported value$947Mas of Sep 30, 2026
Positions76 33 new, 32 sold out
Top 10 weight51.0%PEN alone is 7%
FiledNov 1344 days after quarter end
Portfolio · as of Sep 30, 2026
Where the money is
New or addedTrimmedHeld
PENPenumbra Inc
7.1%Added +39%
WBDWarner Bros Discovery Inc
6.2%Added +8%
TXNMTXNM Energy Inc
5.9%Added +29%
SLABSilicon Laboratories Inc.
5.3%Added +52%
CZRCaesars Entertainment, Inc.
5.1%Added +24%
RAMPLiveRamp Holdings, Inc.
4.9%Added +54%
NSCNorfolk Southern Corp
4.5%Trimmed −6%
TECHBio-techne Corp
4.1%Added +59%
DDominion Energy, Inc
4.0%Added +66%
ACAArcosa Inc
4.0%Added +49%
ROKURoku, Inc
3.8%Added +42%
ITGRInteger Holdings Corp
3.2%
PENPenumbra Inc
7.1%+39%
WBDWarner Bros Discovery Inc
6.2%
TXNMTXNM Energy Inc
5.9%
SLABSilicon Laboratories Inc.
5.3%+52%
CZRCaesars Entertainment, Inc.
5.1%+24%
RAMPLiveRamp Holdings, Inc.
4.9%+54%
NSCNorfolk Southern Corp
4.5%
TECHBio-techne Corp
4.1%
DDominion Energy, Inc
4.0%
ACAArcosa Inc
4.0%
ROKURoku, Inc
3.8%
ITGRInteger Holdings Corp
3.2%
Boxes show the top 12 stocks, sized against each other. The bar above shows how much of the fund they are. 13F only covers US-listed stocks, so foreign holdings and short positions are missing.
Show the top 12 as a list
PEN Penumbra Inc 7.1% Added +39%
WBD Warner Bros Discovery Inc 6.2% Added +8%
TXNM TXNM Energy Inc 5.9% Added +29%SLAB Silicon Laboratories Inc. 5.3% Added +52%CZR Caesars Entertainment, Inc. 5.1% Added +24%RAMP LiveRamp Holdings, Inc. 4.9% Added +54%NSC Norfolk Southern Corp 4.5% Trimmed −6%TECH Bio-techne Corp 4.1% Added +59%D Dominion Energy, Inc 4.0% Added +66%ACA Arcosa Inc 4.0% Added +49%
ROKU Roku, Inc 3.8% Added +42%ITGR Integer Holdings Corp 3.2% NewWhat changed
Biggest moves since Jun 30, 2026
Free weekly email
Each week's biggest real insider buys, cluster buys and fund moves, every one dated. One email a week. Unsubscribe in one click.