Who owns Rambus (RMBS)?
126 holders named in SEC filings declare between 69.5% and 89.1% of Rambus' shares outstanding, as of Jun 30, 2026. The largest are BlackRock (12.9%), Vanguard (10.8%) and Fidelity (FMR) (9.6%); the five largest hold 43.1% together. Another 489 institutions hold small positions worth 4.0%. At least 6.9% of the shares appear in no ownership filing: investors who do not have to report, mostly individuals. From Mar 31, 2026 to Jun 30, 2026, institutions that filed both quarters bought 14.4% and sold 18.3% of the shares, a net sale of 3.9%; 123 opened a position, 181 added, 226 reduced and 64 sold out. Biggest buyers: Fidelity (FMR) (+7.1M shares) and D. E. Shaw (+726,896 shares). Biggest sellers: T. Rowe Price (-2.4M) and BlackRock (-2.3M). Schedule 13D/G filings since Mar 31, 2026: BlackRock, Inc. cut its stake to 12.2% on Jun 30, 2026 and FMR LLC crossed 5% (10.4%) on May 29, 2026. Over time, 608 managers declared Rambus in their 13F for Q2 2026, against 170 for Q4 2019: together at most 92.7% of the shares outstanding, against 82.8%.
| Holder | Filing | Share of capital | As of | Holding since (13F) |
|---|---|---|---|---|
| BlackRock | 13F | 12.9% | Jun 30, 2026 | Q4 2019 or earlier |
| Vanguard | 13F | 10.8% | Jun 30, 2026 | Q4 2019 or earlier |
| Fidelity (FMR) | 13F | 9.6% | Jun 30, 2026 | Q1 2021 |
| Invesco | 13F | 6.1% | Jun 30, 2026 | Q4 2019 or earlier |
| State Street | 13F | 3.6% | Jun 30, 2026 | Q4 2019 or earlier |
| T. Rowe Price | 13F | 3.1% | Jun 30, 2026 | Q1 2021 |
| Geode Capital | 13F | 2.1% | Jun 30, 2026 | Q4 2019 or earlier |
| JPMorgan | 13F | 1.9% | Jun 30, 2026 | Q4 2019 or earlier |
| Dimensional | 13F | 1.6% | Jun 30, 2026 | Q4 2019 or earlier |
| Swedbank AB | 13F | 1.5% | Jun 30, 2026 | Q1 2023 |
| Norges Bank | 13F | 1.4% | Jun 30, 2026 | Q4 2019 or earlier |
| Morgan Stanley | 13F | 1.3% | Jun 30, 2026 | Q4 2019 or earlier |
| Neuberger Berman Group LLC | 13F | 1.2% | Jun 30, 2026 | Q4 2019 or earlier |
| Bank of America | 13F | 1.1% | Jun 30, 2026 | Q4 2019 or earlier |
| AQR | 13F | 1.1% | Jun 30, 2026 | Q4 2019 or earlier |
| Charles Schwab | 13F | 1.0% | Jun 30, 2026 | Q4 2019 or earlier |
| EdgePoint Investment Group Inc. | 13F | 1.0% | Jun 30, 2026 | Q1 2025 |
| Rafferty Asset Management, LLC | 13F | 0.91% | Jun 30, 2026 | Q3 2025 |
| Goldman Sachs | 13F | 0.89% | Jun 30, 2026 | Q4 2019 or earlier |
| BESSEMER GROUP INC | 13F | 0.88% | Jun 30, 2026 | Q1 2023 |
| Northern Trust | 13F | 0.88% | Jun 30, 2026 | Q4 2019 or earlier |
| BNY | 13F | 0.76% | Jun 30, 2026 | Q4 2019 or earlier |
| MANUFACTURERS LIFE INSURANCE COMPANY, THE | 13F | 0.74% | Jun 30, 2026 | Q4 2019 or earlier |
| CONGRESS ASSET MANAGEMENT CO | 13F | 0.72% | Jun 30, 2026 | Q4 2024 |
| PointState Capital LP | 13F | 0.70% | Jun 30, 2026 | Q1 2026 |
Rambus institutional ownership over time
| Quarter | 13F managers | Share of the company (upper bound) | Value declared | Held by stock pickers |
|---|---|---|---|---|
| Q4 2019 | 170 | 82.8% | $1.3B | 50.7% |
| Q4 2020 | 209 | 83.4% | $1.7B | 48.4% |
| Q4 2021 | 242 | 86.5% | $2.8B | 47.9% |
| Q4 2022 | 293 | 84.8% | $3.3B | 43.8% |
| Q4 2023 | 390 | 90.2% | $6.6B | 50.9% |
| Q4 2024 | 384 | 89.2% | $5.0B | 48.1% |
| Q4 2025 | 545 | 92.7% | $9.2B | 47.6% |
| Q2 2026 | 608 | 92.7% | $13.3B | 49.0% |
From SEC Form 13F, every quarter since the end of 2019, read like the current quarter: entities of a house summed, a value contradicting its share count set aside. The share of the company is an upper bound — two managers can declare the same shares — over the shares outstanding at that date.