Rambus Inc (RMBS) shareholders
RMBSNasdaqSemiconductors & Related DevicesFiscal year ends December 31
Financials through Q3 FY2026, quarter ended Sep 30, 2026Last filing: 10-Q on Oct 26, 2026Score 13/303% below fair value
$82.23−2.74 (-3.22%)
Close on Nov 13, 2026Market cap $8.81BP/E 33.8Yield –
Ownership
Institutional holdings as of Jun 30, 2026, from 13F filings
Held by institutions
94.0%
101M of 107M shares
Institutional holders
617
136 new, 66 sold out
Net institutional buying
-2M
In Q2 2026
Insider trades, 12 months
0 buys · 30 sales
Net sold $20.05M
Shares held by institutions
Holders of more than 5%
Latest Schedule 13D (active) or 13G (passive) filed by each holder
| Holder | Shares | % of class | Filing | As of |
|---|---|---|---|---|
| BlackRock, Inc. | 11,268,097 | 10.40% | 13G (passive) amendment | Sep 30, 2026 |
| Abigail P. Johnson Joint filing with FMR LLC (6.60%) | 7,113,727 | 6.60% | 13G (passive) amendment | Sep 30, 2026 |
| Vanguard Portfolio Management | 6,742,464 | 6.23% | 13G (passive) | Mar 31, 2026 |
| Invesco Ltd. | 6,499,048 | 6.00% | 13G (passive) | Mar 31, 2026 |
| Vanguard Capital Management | 5,651,568 | 5.22% | 13G (passive) | Mar 31, 2026 |
Top institutional holders
13F holdings as of Jun 30, 2026
| Holder | Shares | % of RMBS | Value | Change | % of portfolio |
|---|---|---|---|---|---|
| BlackRock, Inc. | 13,964,477 | 13.04% | $1.85B | −2,340,829 | 0.03% |
| FMR LLC | 10,460,026 | 9.77% | $1.39B | +7,141,577 | 0.06% |
| Invesco Ltd. | 6,632,458 | 6.19% | $880.39M | +133,410 | 0.07% |
| Vanguard Portfolio Management LLC | 6,068,516 | 5.67% | $805.53M | −575,804 | 0.04% |
| Vanguard Capital Management LLC | 4,874,385 | 4.55% | $647.03M | +46,531 | 0.01% |
| State Street Corp | 3,915,113 | 3.66% | $519.50M | −458,504 | 0.02% |
| Price T Rowe Associates Inc /Md/ | 3,334,512 | 3.11% | $442.62M | −42,177 | 0.04% |
| Geode Capital Management, LLC | 2,297,660 | 2.15% | $305.06M | −826,835 | 0.02% |
| JPMorgan Chase & Co | 2,101,418 | 1.96% | $260.99M | +264,918 | 0.01% |
| Dimensional Fund Advisors LP | 1,719,400 | 1.61% | $228.19M | −75,895 | 0.04% |
| Swedbank AB | 1,646,500 | 1.54% | $218.56M | +83,500 | 0.19% |
| Norges Bank | 1,532,622 | 1.43% | $203.44M | New | 0.02% |
| Morgan Stanley | 1,444,281 | 1.35% | $191.71M | +231,084 | 0.01% |
| Neuberger Berman Group LLC | 1,311,777 | 1.22% | $173.45M | +9,608 | 0.12% |
| Bank Of America Corp /De/ | 1,218,726 | 1.14% | $161.77M | −142,844 | 0.01% |
| Aqr Capital Management LLC | 1,211,009 | 1.13% | $152.48M | −39,447 | 0.05% |
| Charles Schwab Investment Management Inc | 1,109,132 | 1.04% | $147.23M | −217,270 | 0.02% |
| EdgePoint Investment Group Inc. | 1,086,213 | 1.01% | $144.18M | −861,529 | 1.09% |
| Rafferty Asset Management, LLC | 984,388 | 0.92% | $130.67M | +238,869 | 0.30% |
| Goldman Sachs Group Inc | 960,878 | 0.90% | $127.55M | +38,773 | 0.01% |
Institutional buying and selling by quarter
Positions opened, added to, reduced and closed by 13F filers
| Quarter | Holders | Shares held | % of shares | New / added | Reduced / closed | Shares bought | Shares sold |
|---|---|---|---|---|---|---|---|
| Q2 2026 | 617 | 101M | 94.0% | 136 / 190 | 227 / 66 | 18M | 20M |
| Q1 2026 | 557 | 103M | 96.0% | 85 / 188 | 208 / 75 | 29M | 14M |
| Q4 2025 | 554 | 100M | 93.3% | 103 / 191 | 194 / 53 | 11M | 12M |
| Q3 2025 | 513 | 101M | 94.6% | 123 / 171 | 161 / 62 | 17M | 13M |
| Q2 2025 | 459 | 97M | 91.0% | 88 / 190 | 133 / 39 | 13M | 13M |
| Q1 2025 | 413 | 98M | 91.3% | 78 / 161 | 130 / 54 | 14M | 8M |
| Q4 2024 | 395 | 95M | 88.8% | 78 / 121 | 153 / 51 | 15M | 16M |
| Q3 2024 | 376 | 97M | 90.7% | 77 / 159 | 104 / 62 | 31M | 21M |
| Q2 2024 | 363 | 103M | 96.2% | 53 / 123 | 150 / 62 | 9M | 12M |
| Q1 2024 | 375 | 106M | 99.2% | 52 / 154 | 134 / 71 | 13M | 13M |
| Q4 2023 | 398 | 106M | 98.9% | 93 / 121 | 143 / 39 | 20M | 14M |
| Q3 2023 | 349 | 99M | 92.9% | 40 / 154 | 115 / 82 | 11M | 10M |
Top mutual fund and ETF holders
Latest monthly portfolio reports (Form N-PORT)
561 funds held RMBS in Q2 2026, 47% of their shares through ETFs. Each fund counts once per quarter, from its quarter-end report.
| Fund | Shares | % of RMBS | Value | % of fund | As of |
|---|---|---|---|---|---|
| iShares Core S&P Mid-Cap ETF | 3,700,646 | 3.46% | $491.22M | 0.40% | Jun 30, 2026 |
| Vanguard Total Stock Market Index Fund | 3,431,851 | 3.20% | $455.54M | 0.02% | Jun 30, 2026 |
| Invesco Small Cap Value Fund | 3,046,794 | 2.84% | $277.35M | 2.50% | Jul 31, 2026 |
| Invesco Value Opportunities Fund | 2,496,678 | 2.33% | $227.27M | 2.50% | Jul 31, 2026 |
| Vanguard Small-Cap Index Fund | 2,479,300 | 2.32% | $329.10M | 0.17% | Jun 30, 2026 |
| iShares Semiconductor ETF | 2,294,771 | 2.14% | $304.61M | 0.64% | Jun 30, 2026 |
| Strategic Advisers Fidelity U.S. Total Stock Fund | 1,778,224 | 1.66% | $258.66M | 0.10% | May 31, 2026 |
| Vanguard Small-Cap Growth Index Fund | 1,430,545 | 1.34% | $189.89M | 0.40% | Jun 30, 2026 |
| Vanguard Information Technology Index Fund | 1,423,050 | 1.33% | $207.00M | 0.12% | May 31, 2026 |
| Vanguard Extended Market Index Fund | 1,240,011 | 1.16% | $164.60M | 0.17% | Jun 30, 2026 |
| Vanguard Explorer Fund | 1,049,546 | 0.98% | $95.54M | 0.43% | Jul 31, 2026 |
| Direxion Daily Semiconductor Bull 3X Shares | 818,275 | 0.76% | $74.49M | 0.38% | Jul 31, 2026 |
| VIP Mid Cap Portfolio | 784,100 | 0.73% | $104.08M | 1.09% | Jun 30, 2026 |
| JPMorgan Mid Cap Growth Fund | 783,021 | 0.73% | $103.94M | 0.79% | Jun 30, 2026 |
| Invesco S&P MidCap Momentum ETF | 677,044 | 0.63% | $61.63M | 0.86% | Jul 31, 2026 |
Officers, directors and major owners
People who filed Forms 3, 4 or 5 in the last two years
| Name | Role | Shares owned | % of shares | Latest filing |
|---|---|---|---|---|
| Luc Seraphin | President and CEO, Director | 345,767 | 0.32% | Apr 3, 2026 |
| William Clarence Taulbee II | Chief Accounting Officer | 8,293 | 0.01% | Sep 15, 2026 |
| John Shinn | SVP, General Counsel | 21,112 | 0.02% | May 26, 2026 |
| Xianzhi Sean Fan | EVP, COO | 168,358 | 0.16% | May 26, 2026 |
| Sumeet Gagneja | SVP, CFO | 41,320 | 0.04% | May 4, 2026 |
| John K. Allen | Chief Accounting Officer | 17,131 | 0.02% | Apr 7, 2026 |
| Desmond Lynch | SVP, CFO | 63,618 | 0.06% | Feb 24, 2026 |
| Charles Kissner | Director | 44,292 | 0.04% | Oct 5, 2026 |
| Emiko Higashi | Director | 54,519 | 0.05% | Jun 3, 2026 |
| Necip Sayiner | Director | 18,223 | 0.02% | Jun 3, 2026 |
| Eric B. Stang | Director | 21,441 | 0.02% | Jun 2, 2026 |
| Steven Laub | Director | 7,519 | 0.01% | May 11, 2026 |
| Meera Rao | Director | 19,974 | 0.02% | Apr 27, 2026 |
| Victor Peng | Director | 2,391 | 0.00% | Apr 3, 2026 |
Insider trades
Common stock transactions reported on Form 4, newest first
| Insider | Date | Transaction | Shares | Price | Value | Shares after |
|---|---|---|---|---|---|---|
| Charles Kissner Director | Oct 2, 2026 | Sale(10b5-1 plan) | −5,000 | $111.00 | $555.00K | 3,747 |
| Charles Kissner Director | Sep 22, 2026 | Sale(10b5-1 plan) | −5,000 | $105.00 | $525.00K | 8,747 |
| Charles Kissner Director | Aug 7, 2026 | Sale(10b5-1 plan) | −5,000 | $100.92 | $504.60K | 13,747 |
| Necip Sayiner Director | Jun 3, 2026 | Sale | −5,000 | $170.15 | $850.75K | 18,223 |
| Emiko Higashi Director | Jun 2, 2026 | Sale | −5,000 | $163.00 | $815.00K | 54,519 |
| Emiko Higashi Director | Jun 2, 2026 | Sale | −5,000 | $158.00 | $790.00K | 49,519 |
| Eric B. Stang Director | Jun 1, 2026 | Sale | −5,000 | $146.00 | $730.00K | 19,218 |
| Emiko Higashi Director | May 26, 2026 | Sale | −5,000 | $157.57 | $787.85K | 59,519 |
| Xianzhi Sean Fan EVP, COO | May 26, 2026 | Sale | −100 | $152.35 | $15.24K | 168,358 |
| Xianzhi Sean Fan EVP, COO | May 26, 2026 | Sale | −37,814 | $151.69 | $5.74M | 168,458 |
| John Shinn SVP, General Counsel | May 22, 2026 | Sale | −1,000 | $143.63 | $143.63K | 21,112 |
| Necip Sayiner Director | May 8, 2026 | Sale | −9,824 | $130.18 | $1.28M | 23,223 |
| Steven Laub Director | May 7, 2026 | Sale | −1,500 | $125.52 | $188.28K | 7,519 |
| Sumeet Gagneja SVP, CFO | May 1, 2026 | Award | +26,802 | – | – | 41,320 |
| Sumeet Gagneja SVP, CFO | May 1, 2026 | Award | +14,518 | – | – | 14,518 |
| Meera Rao Director | Apr 24, 2026 | Sale(10b5-1 plan) | −2,972 | $150.30 | $446.69K | 19,974 |
| Meera Rao Director | Apr 14, 2026 | Sale(10b5-1 plan) | −8,538 | $118.08 | $1.01M | 22,946 |
| John K. Allen Chief Accounting Officer | Apr 3, 2026 | Tax withholding | −1,131 | $92.22 | $104.30K | 17,131 |
| Luc Seraphin President and CEO, Director | Apr 2, 2026 | Sale(10b5-1 plan) | −165 | $88.35 | $14.58K | 345,767 |
| Luc Seraphin President and CEO, Director | Apr 2, 2026 | Sale(10b5-1 plan) | −2,750 | $87.11 | $239.55K | 345,932 |
| Luc Seraphin President and CEO, Director | Apr 2, 2026 | Sale(10b5-1 plan) | −2,511 | $86.04 | $216.05K | 348,682 |
| Charles Kissner Director | Apr 1, 2026 | Award | +2,223 | – | – | 40,545 |
| Xianzhi Sean Fan EVP, COO | Apr 1, 2026 | Tax withholding | −9,916 | $89.95 | $891.94K | 206,272 |
| Xianzhi Sean Fan EVP, COO | Apr 1, 2026 | Award | +22,234 | – | – | 216,188 |
| Steven Laub Director | Apr 1, 2026 | Award | +2,223 | – | – | 9,019 |
| Necip Sayiner Director | Apr 1, 2026 | Award | +2,223 | – | – | 33,047 |
| Luc Seraphin President and CEO, Director | Apr 1, 2026 | Award | +32,684 | – | – | 363,754 |
| Luc Seraphin President and CEO, Director | Apr 1, 2026 | Tax withholding | −12,561 | $89.95 | $1.13M | 351,193 |
| John Shinn SVP, General Counsel | Apr 1, 2026 | Tax withholding | −1,913 | $89.95 | $172.07K | 22,112 |
| John Shinn SVP, General Counsel | Apr 1, 2026 | Award | +5,558 | – | – | 24,025 |
| Victor Peng Director | Apr 1, 2026 | Award | +2,223 | – | – | 2,391 |
| Meera Rao Director | Apr 1, 2026 | Award | +2,223 | – | – | 31,484 |
| John K. Allen Chief Accounting Officer | Apr 1, 2026 | Award | +2,779 | – | – | 19,415 |
| John K. Allen Chief Accounting Officer | Apr 1, 2026 | Tax withholding | −495 | $89.95 | $44.53K | 18,920 |
| John K. Allen Chief Accounting Officer | Apr 1, 2026 | Tax withholding | −658 | $89.95 | $59.19K | 18,262 |
| Emiko Higashi Director | Apr 1, 2026 | Award | +2,223 | – | – | 64,519 |
| Eric B. Stang Director | Apr 1, 2026 | Award | +2,223 | – | – | 2,223 |
| John Shinn SVP, General Counsel | Mar 10, 2026 | Sale(10b5-1 plan) | −4,356 | $88.64 | $386.12K | 18,667 |
| John Shinn SVP, General Counsel | Mar 10, 2026 | Sale(10b5-1 plan) | −200 | $89.55 | $17.91K | 18,467 |
| John Shinn SVP, General Counsel | Mar 3, 2026 | Sale(10b5-1 plan) | −700 | $94.89 | $66.42K | 23,023 |
| John Shinn SVP, General Counsel | Mar 3, 2026 | Sale(10b5-1 plan) | −2,254 | $92.77 | $209.10K | 25,326 |
| John Shinn SVP, General Counsel | Mar 3, 2026 | Sale(10b5-1 plan) | −1,603 | $94.07 | $150.79K | 23,723 |
| Luc Seraphin President and CEO, Director | Mar 2, 2026 | Sale(10b5-1 plan) | −6,587 | $100.20 | $660.02K | 332,370 |
| Luc Seraphin President and CEO, Director | Mar 2, 2026 | Sale(10b5-1 plan) | −1,300 | $101.65 | $132.15K | 331,070 |
| Luc Seraphin President and CEO, Director | Mar 2, 2026 | Sale(10b5-1 plan) | −7,225 | $97.38 | $703.57K | 362,080 |
| Luc Seraphin President and CEO, Director | Mar 2, 2026 | Sale(10b5-1 plan) | −13,654 | $98.22 | $1.34M | 348,426 |
| Luc Seraphin President and CEO, Director | Mar 2, 2026 | Sale(10b5-1 plan) | −9,469 | $99.17 | $939.04K | 338,957 |
| Luc Seraphin President and CEO, Director | Mar 2, 2026 | Sale(10b5-1 plan) | −1,679 | $95.83 | $160.90K | 369,305 |
| Victor Peng Director | Mar 2, 2026 | Award | +168 | – | – | 168 |
| Desmond Lynch SVP, CFO | Feb 23, 2026 | Sale(10b5-1 plan) | −4,273 | $101.53 | $433.84K | 63,618 |
| John Shinn SVP, General Counsel | Feb 1, 2026 | Award | +17,276 | – | – | 37,464 |
| John Shinn SVP, General Counsel | Feb 1, 2026 | Tax withholding | −9,884 | $113.71 | $1.12M | 27,580 |
| Desmond Lynch SVP, CFO | Feb 1, 2026 | Tax withholding | −22,105 | $113.71 | $2.51M | 67,891 |
| Desmond Lynch SVP, CFO | Feb 1, 2026 | Award | +34,554 | – | – | 89,996 |
| Xianzhi Sean Fan EVP, COO | Feb 1, 2026 | Award | +148,802 | – | – | 286,357 |
| Xianzhi Sean Fan EVP, COO | Feb 1, 2026 | Tax withholding | −92,403 | $113.71 | $10.51M | 193,954 |
| Luc Seraphin President and CEO, Director | Feb 1, 2026 | Award | +143,744 | – | – | 463,507 |
| Luc Seraphin President and CEO, Director | Feb 1, 2026 | Tax withholding | −92,523 | $113.71 | $10.52M | 370,984 |
| Xianzhi Sean Fan EVP, COO | Nov 21, 2025 | Gift | −300 | – | – | 137,555 |
| Xianzhi Sean Fan EVP, COO | Nov 19, 2025 | Gift | −300 | – | – | 137,855 |
Awards, option exercises, tax withholding and gifts are shown alongside open-market buys and sales. Each name links to the filing on SEC EDGAR.
Short interest
Shares sold short and not yet bought back, as of Oct 30, 2026 (FINRA, reported twice a month)
Short % of float
4.21%
4M shares short
Days to cover
2.1
At 2M shares a day
Change since last report
+4.4%
From 4M shares
Short volume, 20 days
36.8%
Of volume reported to FINRA
Shares sold short, last 12 months
Short sale volume counts trades marked short on any given day, including market-maker hedging, so it runs far higher than the share of Rambus's stock actually held short. Settlement fails (shares not delivered on time) peaked at 65,128 shares on Oct 13, 2026 over the last 90 days.
Planned insider sales
Notices of proposed sale filed on Form 144 before shares are sold
| Seller | Filed | Shares | Market value | Planned sale | Acquired through |
|---|---|---|---|---|---|
| Charles Kissner Director | Oct 2, 2026 | 5,000 | $555.00K | Oct 2, 2026 | RSU |
| Charles Kissner Director | Sep 22, 2026 | 5,000 | $525.00K | Sep 22, 2026 | RSU |
| Charles Kissner Director | Aug 7, 2026 | 5,000 | $504.60K | Aug 7, 2026 | RSU |
| Necip Sayiner Officer | Jun 3, 2026 | 5,000 | $850.75K | Jun 3, 2026 | Restricted Stock |
| Emiko Higashi Director | Jun 2, 2026 | 10,000 | $1.61M | Jun 2, 2026 | Restricted Stock |
| Stang Family Trust Affiliate | Jun 1, 2026 | 5,000 | $730.00K | Jun 1, 2026 | Restricted stock vesting under a registered plan |
| Xianzhi Sean Fan Officer | May 26, 2026 | 37,914 | $5.75M | May 26, 2026 | Performance Shares |
| Emiko Higashi Director | May 26, 2026 | 5,000 | $787.85K | May 26, 2026 | Restricted Stock |
| John Shinn Officer | May 22, 2026 | 1,000 | $143.63K | May 22, 2026 | Restricted Stock |
| Necip Sayiner Director | May 8, 2026 | 9,824 | $1.28M | May 8, 2026 | Restricted Stock |
| Steven Laub Director | May 7, 2026 | 1,500 | $188.28K | May 7, 2026 | Restricted Stock |
| Meera Rao Director | Apr 24, 2026 | 2,972 | $446.69K | Apr 24, 2026 | Restricted Stock |
| Meera Rao Director | Apr 14, 2026 | 8,538 | $1.01M | Apr 14, 2026 | Restricted Stock |
| Luc Seraphin Officer, Director | Apr 2, 2026 | 5,426 | $470.19K | Apr 2, 2026 | Restricted Stock |
| Desmond Lynch Officer | Apr 2, 2026 | 1,586 | $135.92K | Apr 2, 2026 | Restricted Stock |
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