Rambus Inc. (RMBS) Ownership
RMBS ownership summary
as of October 18, 2026- Institutions
- 94.4% of shares outstanding
- Insiders
- 0.77% of shares outstanding
- Shares outstanding
- 108.5M
- Float
- 107.6M shares available to trade
- Short interest
- 5.98% 4.8M shares short
- Days to cover
- 1.78 short interest down 23.1% vs prior month
- Institutions 94.37%
- Insiders 0.77%
- Other investors 4.87%
RMBS top institutional holders
20 largest| # | Holder | % of shares | Shares | Value | Change | Reported |
|---|---|---|---|---|---|---|
| 1 | BlackRock Inc | 12.88% | 14.0M | $1.22B | −2.3M (−14.4%) | June 30, 2026 |
| 2 | FMR Inc | 9.64% | 10.5M | $912.6M | +7.1M (+215.2%) | June 30, 2026 |
| 3 | Amvescap Plc. | 6.12% | 6.6M | $578.7M | +133,410 (+2.1%) | June 30, 2026 |
| 4 | Vanguard Portfolio Management, LLC | 5.60% | 6.1M | $529.5M | −575,804 (−8.7%) | June 30, 2026 |
| 5 | Vanguard Capital Management, LLC | 4.49% | 4.9M | $425.3M | +46,531 (+1.0%) | June 30, 2026 |
| 6 | State Street Corp | 3.61% | 3.9M | $341.6M | −458,504 (−10.5%) | June 30, 2026 |
| 7 | T. Rowe Price Associates, Inc. | 3.07% | 3.3M | $290.9M | −42,177 (−1.2%) | June 30, 2026 |
| 8 | Geode Capital Management, LLC | 2.12% | 2.3M | $200.5M | −826,835 (−26.5%) | June 30, 2026 |
| 9 | JPMorgan Chase & Co | 1.94% | 2.1M | $183.3M | +264,918 (+14.4%) | June 30, 2026 |
| 10 | Dimensional Fund Advisors, Inc. | 1.59% | 1.7M | $150.0M | −75,895 (−4.2%) | June 30, 2026 |
| 11 | Swedbank AB | 1.52% | 1.6M | $143.7M | +83,500 (+5.3%) | June 30, 2026 |
| 12 | NORGES BANK | 1.41% | 1.5M | $133.7M | −168,929 (−9.9%) | June 30, 2026 |
| 13 | Morgan Stanley - Brokerage Accounts | 1.33% | 1.4M | $126.0M | +231,084 (+19.0%) | June 30, 2026 |
| 14 | Neuberger Berman Group LLC | 1.21% | 1.3M | $114.5M | +9,608 (+0.7%) | June 30, 2026 |
| 15 | Bank of America Corp | 1.12% | 1.2M | $106.3M | −142,844 (−10.5%) | June 30, 2026 |
| 16 | AQR Capital Management LLC | 1.12% | 1.2M | $105.7M | −39,447 (−3.2%) | June 30, 2026 |
| 17 | Charles Schwab Investment Management Inc | 1.02% | 1.1M | $96.8M | −217,270 (−16.4%) | June 30, 2026 |
| 18 | EdgePoint Investment | 1.00% | 1.1M | $94.8M | −861,529 (−44.2%) | June 30, 2026 |
| 19 | Rafferty Asset Management, LLC | 0.91% | 984K | $85.9M | +238,869 (+32.0%) | June 30, 2026 |
| 20 | The Goldman Sachs Group Inc | 0.89% | 961K | $83.8M | +38,773 (+4.2%) | June 30, 2026 |
Value at the latest close. Change = shares bought or sold in the latest quarterly filing (13F). In the top 20, 9 holders added 8.2M shares and 11 cut 5.8M.
RMBS top mutual fund and ETF holders
20 largest| # | Holder | % of shares | Shares | Value | Change | Reported |
|---|---|---|---|---|---|---|
| 1 | iShares Core S&P Mid-Cap ETF | 3.56% | 3.9M | $337.1M | −1,380 (−0.0%) | September 30, 2026 |
| 2 | Vanguard MStar Total Stk Mkt Idx Invest | 3.17% | 3.4M | $300.0M | −3,912 (−0.1%) | August 31, 2026 |
| 3 | Vanguard Small Cap Index | 2.25% | 2.4M | $213.0M | −46,740 (−1.9%) | September 30, 2026 |
| 4 | Strategic Advisers Fidelity US TtlStk | 1.92% | 2.1M | $181.3M | +60,296 (+3.0%) | August 31, 2026 |
| 5 | Invesco Small Cap Value A | 1.84% | 2.0M | $174.4M | −1.0M (−34.4%) | August 31, 2026 |
| 6 | Invesco Value Opportunities A | 1.58% | 1.7M | $149.2M | −786,722 (−31.5%) | August 31, 2026 |
| 7 | Swedbank Robur Technology A | 1.29% | 1.4M | $122.2M | — | September 30, 2026 |
| 8 | Vanguard MStar Small Cap Growth Indx Inv | 1.25% | 1.4M | $118.4M | −70,569 (−4.9%) | September 30, 2026 |
| 9 | Vanguard Information Technology ETF | 1.24% | 1.3M | $117.6M | +3,105 (+0.2%) | September 30, 2026 |
| 10 | EdgePoint Global Portfolio Series F | 0.94% | 1.0M | $88.8M | +289,073 (+39.7%) | March 31, 2026 |
| 11 | Vanguard Explorer Inv | 0.93% | 1.0M | $87.9M | +266,019 (+35.9%) | June 30, 2026 |
| 12 | Fidelity VIP Mid Cap Initial | 0.78% | 848K | $74.0M | +20,400 (+2.5%) | August 31, 2026 |
| 13 | State Street® SPDR® S&P® Smcndctr ETF | 0.76% | 823K | $71.8M | +3,492 (+0.4%) | September 30, 2026 |
| 14 | Fidelity Series Large Cap Stock | 0.74% | 808K | $70.5M | — | August 31, 2026 |
| 15 | State Street® SPDR® S&P MIDCAP 400® ETF | 0.74% | 802K | $70.0M | +11,140 (+1.4%) | September 30, 2026 |
| 16 | Invesco Equity and Income A | 0.73% | 789K | $68.9M | — | August 31, 2026 |
| 17 | iShares S&P Mid-Cap 400 Growth ETF | 0.58% | 626K | $54.6M | −668 (−0.1%) | September 30, 2026 |
| 18 | iShares Russell Mid-Cap Growth ETF | 0.56% | 605K | $52.8M | −645 (−0.1%) | September 30, 2026 |
| 19 | T. Rowe Price Integrated US Sm Gr Eq | 0.55% | 592K | $51.7M | +25,600 (+4.5%) | September 30, 2026 |
| 20 | State Street SPDR Port S&P 400 Md CpETF | 0.53% | 573K | $50.0M | −808 (−0.1%) | September 30, 2026 |
Funds report holdings monthly or quarterly; dates differ by fund.
RMBS insider transactions
latest 15| Date | Name | Transaction | Price | Shares | Value |
|---|---|---|---|---|---|
| 2026-04-14 | Meera Rao | Sell | $118.08 | 8,538 | $1.0M |
| 2026-04-02 | Luc Seraphin | Sell | $86.65 | 5,426 | $470,163 |
| 2026-03-02 | Luc Seraphin | Sell | $98.63 | 39,914 | $3.9M |
| 2026-02-23 | Desmond Lynch | Sell | $101.53 | 4,273 | $433,838 |
| 2025-11-10 | Eric B Stang | Sell | $111.78 | 4,000 | $447,120 |
| 2025-11-07 | Eric B Stang | Sell | $102.35 | 5,000 | $511,750 |
| 2025-10-01 | Meera Rao | Sell | $101.99 | 653 | $66,599 |
| 2025-09-15 | Desmond Lynch | Sell | $91.70 | 9,074 | $832,086 |
| 2025-09-11 | Necip Sayiner | Sell | $85.63 | 7,500 | $642,225 |
| 2025-09-02 | Meera Rao | Sell | $71.72 | 3,000 | $215,160 |
| 2025-08-13 | Emiko Higashi | Sell | $77.75 | 1,075 | $83,581 |
| 2025-08-08 | Necip Sayiner | Sell | $73.53 | 7,500 | $551,475 |
| 2025-08-04 | Emiko Higashi | Sell | $75.00 | 1,111 | $83,325 |
| 2025-05-27 | Steven Laub | Sell | $55.12 | 1,847 | $101,807 |
| 2025-05-19 | Steven Laub | Sell | $55.56 | 3,653 | $202,961 |
Reported trades by company officers, directors and other filers (including disclosures by members of Congress where EODHD lists them). "—" where the filing gives no share count.
RMBS shares outstanding
Year-end shares outstanding, adjusted for splits.
Who owns RMBS
Institutional investors own 94.4% of Rambus's shares and insiders 0.77%. The largest holder is BlackRock Inc with 12.88% of the shares (14.0M), as of June 30, 2026. Among the top 20 institutions, 9 added shares and 11 reduced their stake in the latest filings. Short interest is 5.98% of the float, or 1.78 days of average trading volume. The share count fell 6.7% since 2014.
Related: RMBS analyst forecast, RMBS key metrics. See the RMBS stock overview for the latest quote and news.
RMBS ownership FAQ
Who owns the most Rambus stock?
The largest shareholders of Rambus are BlackRock Inc (12.88%), FMR Inc (9.64%), Amvescap Plc. (6.12%), Vanguard Portfolio Management, LLC (5.60%), Vanguard Capital Management, LLC (4.49%).
What percentage of Rambus is owned by institutions?
Institutions hold 94.4% of Rambus's shares outstanding; insiders hold 0.77%.
Which funds own Rambus?
The largest fund holders of Rambus are iShares Core S&P Mid-Cap ETF (3.56%), Vanguard MStar Total Stk Mkt Idx Invest (3.17%), Vanguard Small Cap Index (2.25%), Strategic Advisers Fidelity US TtlStk (1.92%), Invesco Small Cap Value A (1.84%).
What is Rambus's short interest?
4.8M shares of Rambus were sold short, 5.98% of the float; at the average daily volume it would take 1.78 days to cover.
Are insiders buying or selling Rambus?
Of the latest 15 reported insider transactions in Rambus (since May 19, 2025), 0 were purchases and 15 were sales.
How many shares of Rambus are outstanding?
Rambus has 108.5M shares outstanding, of which 107.6M are in the public float.