PubMatic
PUBM
153 hedge funds and large institutions have $236M invested in PubMatic in 2026 Q1 according to their latest regulatory filings, with 33 funds opening new positions, 59 increasing their positions, 41 reducing their positions, and 30 closing their positions.
200% more funds holding in top 10
Funds holding in top 10: 1 → 3 (+2)
44% more repeat investments, than reductions
Existing positions increased: 59 | Existing positions reduced: 41
10% more first-time investments, than exits
New positions opened: 33 | Existing positions closed: 30
1.22% more ownership
Funds ownership: 72.46% → 73.68% (+1.2%)
1% more funds holding
Funds holding: 152 → 153 (+1)
4% less capital invested
Capital invested by funds: $245M → $236M (-$9.26M)
21% less call options, than puts
Call options by funds: $7.64M | Put options by funds: $9.72M
Top Buyers
| Rank | Fund | Capital Flow |
|---|---|---|
| 1 |
WCM
Whitefort Capital Management
New York
|
+$5.3M |
| 2 |
Acadian Asset Management
Boston,
Massachusetts
|
+$5M |
| 3 |
CP
CenterBook Partners
Greenwich,
Connecticut
|
+$4.57M |
| 4 |
GHC
Graham Holdings Company
Arlington,
Virginia
|
+$4.36M |
| 5 |
SST
S Squared Technology
New York
|
+$3.04M |
Top Sellers
| Rank | Fund | Capital Flow |
|---|---|---|
| 1 |
Wellington Management Group
Boston,
Massachusetts
|
-$10.4M |
| 2 |
Millennium Management
New York
|
-$6.35M |
| 3 |
AG
Algert Global
San Francisco,
California
|
-$2.79M |
| 4 |
Walleye Capital
New York
|
-$1.39M |
| 5 |
Marshall Wace
London,
United Kingdom
|
-$1.29M |
PUBM Hedge Fund Activity: Q1 2026 in Review
153 of the 8,126 institutional investors tracked by Wall St. Rank reported a position in PubMatic (PUBM) for Q1 2026, worth a combined $236M — down 3.8% from $245M a quarter earlier.
Buyers outnumbered sellers: 33 funds opened new PUBM positions and 30 closed out — a net gain of 3 holders — while 59 added to existing stakes and 41 trimmed.
The largest buyer was Whitefort Capital Management, opening a new position worth an estimated $5.3M. The largest seller was Wellington Management Group, exiting entirely with an estimated $10.4M sold.
- 153 institutional investors held PubMatic (PUBM) as of Q1 2026, up from 152 in Q4 2025.
- Funds reported $236M of PubMatic stock for Q1 2026, down 3.8% quarter-over-quarter.
- 33 funds opened new PubMatic positions in Q1 2026 and 30 closed out, a net change of +3 holders.
- The largest PubMatic buyer in Q1 2026 was Whitefort Capital Management, an estimated $5.3M added.
- The largest PubMatic seller in Q1 2026 was Wellington Management Group, an estimated $10.4M sold.
Based on aggregated 13F filings for Q1 2026.