Rambus Inc.
Rambus Inc. (RMBS) Stock Ownership
Institutional vs insider vs public ownership from 13F and float data — top holders, activity, and insider trades below.
SEC 13F · FMP · RMBS · as of Sep 30, 2025
Ownership Breakdown
545
Institutional Holders
▲ 65 vs Q2
$10.29B
Total Inst. Value
▲ $4.07B vs Q2
108.14M
Shares Outstanding
freeFloat 99.21%
98.81M
13F Shares Held
▲ 1.58M vs Q2
Institutional ownership = 13F shares ÷ total outstanding. Insider % = 100 − free float. Public % = free float − institution %. Data: FMP /symbol-positions-summary + /shares-float + SEC EDGAR.
Top Institutional Holders
RMBS largest shareholders · institutional ownership
Q3 2025 · SEC 13F
Showing top 10 holders
| Holder | Shares | % Owned | Weight | Value | Reported | Change |
|---|---|---|---|---|---|---|
BLACKROCK, INC. semiconductors & related devices | 15.81M | 14.72% | 14.72% | $1.65T | Nov 12, 2025 | ▲ 808.6K |
VANGUARD GROUP INC semiconductors & related devices | 12.70M | 11.83% | 11.83% | $1.32T | Nov 7, 2025 | ▲ 140.9K |
PRICE T ROWE ASSOCIATES INC /MD/ semiconductors & related devices | 5.25M | 4.88% | 4.88% | $546.57B | Nov 14, 2025 | ▲ 552.0K |
STATE STREET CORP semiconductors & related devices | 4.39M | 4.09% | 4.09% | $457.44B | Nov 14, 2025 | ▼ 119.0K |
GEODE CAPITAL MANAGEMENT, LLC semiconductors & related devices | 2.75M | 2.56% | 2.56% | $286.43B | Nov 12, 2025 | ▲ 60.8K |
EDGEPOINT INVESTMENT GROUP INC. semiconductors & related devices | 2.68M | 2.50% | 2.50% | $279.56B | Nov 14, 2025 | ▼ 104.4K |
JPMORGAN CHASE & CO semiconductors & related devices | 2.56M | 2.38% | 2.38% | $266.42B | Nov 26, 2025 | ▼ 623.5K |
INVESCO LTD. semiconductors & related devices | 2.43M | 2.26% | 2.26% | $253.42B | Nov 13, 2025 | ▲ 109.9K |
DIMENSIONAL FUND ADVISORS LP semiconductors & related devices | 1.93M | 1.80% | 1.80% | $200.97B | Nov 12, 2025 | ▲ 11.0K |
ALLIANCEBERNSTEIN L.P. semiconductors & related devices | 1.82M | 1.70% | 1.70% | $189.86B | Nov 14, 2025 | ▲ 1.55M |
Data from SEC Form 13F filings. Ownership bar normalised to largest holder. Change flags: isNew / isSoldOut / changeInSharesNumber (FMP extract-analytics/holder).
Institutional Activity
Q3 2025 vs prior quarter
Q3 2025
28
Increased
+10.26M shares1
New Positions
first time holders20
Decreased
−3.71M shares0
Sold Out
fully exitedNet shares change (top 50)
+6.55M
+10.26M / −3.71M
Net new holders
+9
1 new / 0 exited
Based on top 50 institutional holders by position size. Fields: isNew, isSoldOut, changeInSharesNumber (FMP extract-analytics/holder, limit=50).
Insider Buying vs Selling
RMBS insider trading · insider activity
Source: SEC Form 4
Insiders have been primarily selling shares recently. Selling may be driven by pre-scheduled Rule 10b5-1 plans rather than negative sentiment.
13
Buy transactions
21
Sell transactions
0.62
Buy/Sell ratio
$0M
Total disposed
Recent Insider Transactions
Showing 10 most recent · Common Stock only
| Name · Role | Date | Type | Shares | Price | Value | After Trans. | Filing |
|---|---|---|---|---|---|---|---|
Sayiner Necip director | Jun 3, 2026 | Sale | 5,000 | $170.15 | $850.8K | 18.2K | Form 4 ↗ |
Higashi Emiko director | Jun 2, 2026 | Sale | 5,000 | $163.00 | $815.0K | 54.5K | Form 4 ↗ |
Higashi Emiko director | Jun 2, 2026 | Sale | 5,000 | $158.00 | $790.0K | 49.5K | Form 4 ↗ |
STANG ERIC B director | Jun 1, 2026 | Sale | 5,000 | $146.00 | $730.0K | 19.2K | Form 4 ↗ |
Higashi Emiko director | May 26, 2026 | Sale | 5,000 | $157.57 | $787.9K | 59.5K | Form 4 ↗ |
FAN XIANZHI SEAN EVP, COO | May 26, 2026 | Sale | 37,814 | $151.69 | $5.74M | 168.5K | Form 4 ↗ |
FAN XIANZHI SEAN EVP, COO | May 26, 2026 | Sale | 100 | $152.35 | $15.2K | 168.4K | Form 4 ↗ |
Shinn John SVP, General Counsel | May 22, 2026 | Sale | 1,000 | $143.63 | $143.6K | 21.1K | Form 4 ↗ |
Sayiner Necip director | May 8, 2026 | Sale | 9,824 | $130.18 | $1.28M | 23.2K | Form 4 ↗ |
LAUB STEVEN director | May 7, 2026 | Sale | 1,500 | $125.52 | $188.3K | 7.5K | Form 4 ↗ |
Source: /insider-trading/search (FMP stable). Buy/Sell direction: acquisitionOrDisposition A=Buy, D=Sell. RSU vesting (M-Exempt) excluded from sentiment bar. All data from SEC EDGAR public filings.
About institutional & insider ownership
Rambus Inc. (RMBS) is primarily owned by institutional investors, who hold approximately 91.4% of total shares outstanding. Company insiders own approximately 0.79%, while retail and public investors account for the remaining 7.84%.
The largest institutional shareholder of Rambus Inc. is BLACKROCK, INC., holding approximately 15.81 million shares — equal to 14.72% of outstanding shares — as of September 30, 2025.
A total of 545 institutional investors currently hold RMBS stock, with a combined institutional value of approximately $10.29 billion as of the most recent 13F filing period.
Frequently asked questions
RMBS ownershipRambus Inc. (RMBS) is primarily owned by institutional investors, who hold approximately 91.4% of shares. The largest shareholder is BLACKROCK, INC. with a 14.72% stake. Company insiders hold 0.79%. Data sourced from SEC Form 13F as of September 30, 2025.