Rambus
RMBS
513 hedge funds and large institutions have $10.3B invested in Rambus in 2025 Q3 according to their latest regulatory filings, with 123 funds opening new positions, 169 increasing their positions, 163 reducing their positions, and 62 closing their positions.
500% more funds holding in top 10
Funds holding in top 10: 1 → 6 (+5)
98% more first-time investments, than exits
New positions opened: 123 | Existing positions closed: 62
65% more capital invested
Capital invested by funds: $6.22B → $10.3B (+$4.07B)
63% more call options, than puts
Call options by funds: $155M | Put options by funds: $94.8M
12% more funds holding
Funds holding: 459 → 513 (+54)
1.36% more ownership
Funds ownership: 90.43% → 91.78% (+1.4%)
4% more repeat investments, than reductions
Existing positions increased: 169 | Existing positions reduced: 163
Top Buyers
| Rank | Fund | Capital Flow |
|---|---|---|
| 1 |
AllianceBernstein
Nashville,
Tennessee
|
+$120M |
| 2 |
Fidelity Investments
Boston,
Massachusetts
|
+$79.8M |
| 3 |
Bank of America
Charlotte,
North Carolina
|
+$79.2M |
| 4 |
Rafferty Asset Management
New York
|
+$69.5M |
| 5 |
BlackRock
New York
|
+$62.3M |
Top Sellers
| Rank | Fund | Capital Flow |
|---|---|---|
| 1 |
WHG
Westwood Holdings Group
Dallas,
Texas
|
-$116M |
| 2 |
Assenagon Asset Management
Senningerberg,
Luxembourg
|
-$60.7M |
| 3 |
JP Morgan Chase
New York
|
-$48.1M |
| 4 |
PWAM
Park West Asset Management
San Francisco,
California
|
-$42.3M |
| 5 |
Westfield Capital Management
Boston,
Massachusetts
|
-$36.8M |
RMBS Hedge Fund Activity: Q3 2025 in Review
513 of the 7,620 institutional investors tracked by Wall St. Rank reported a position in Rambus (RMBS) for Q3 2025, worth a combined $10.3B — up 65% from $6.22B a quarter earlier.
Buyers outnumbered sellers: 123 funds opened new RMBS positions and 62 closed out — a net gain of 61 holders — while 169 added to existing stakes and 163 trimmed.
The largest buyer was AllianceBernstein, adding an estimated $120M. The largest seller was Westwood Holdings Group, cutting an estimated $116M.
- 513 institutional investors held Rambus (RMBS) as of Q3 2025, up from 459 in Q2 2025.
- Funds reported $10.3B of Rambus stock for Q3 2025, up 65% quarter-over-quarter.
- 123 funds opened new Rambus positions in Q3 2025 and 62 closed out, a net change of +61 holders.
- The largest Rambus buyer in Q3 2025 was AllianceBernstein, an estimated $120M added.
- The largest Rambus seller in Q3 2025 was Westwood Holdings Group, an estimated $116M sold.
Based on aggregated 13F filings for Q3 2025.