Rambus Inc.
US ˙ NasdaqGS ˙ US7509171069

SecurityRMBS / Rambus Inc.
InstitutionAlliancebernstein L.p.
Latest Disclosed Ownership267,189 shares
Latest Disclosed Value $ 24,551,997
Alliancebernstein L.p. reports 85.94% decrease in ownership of RMBS / Rambus Inc.

On May 15, 2026 - Alliancebernstein L.p. filed a 13F-HR form disclosing ownership of 267,189 shares of Rambus Inc. (US:RMBS) valued at $22,986,270 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 17, 2026 disclosing 1,900,308 shares of Rambus Inc.. This represents a change in shares of -85.94% during the quarter. The current value of the position is $45,598,475 USD.

Institutional Ownership: 13F and NPORT Filings

The Security and Class in the table below are shown exactly as filed by the investor. We do our best to track continuity of investments through acquisitions, and this will be reflected in the table as changes in names. In addition to descriptive data, performance of the investment is shown over time. To calculate quarterly performance, we first calculate cost basis of the shares purchased during the quarter, then use that to calculate gross profit. Quarterly return is Gross Profit / Starting Portfolio value.

Note that cost basis is calculated and stored in thousands, so small quarterly changes in shares frequently result in a cost basis of zero.

Upgrade to unlock premium data and export to Excel .

Disclosed Equity Positions (from 13F/NPORT Filings)
File
Date		 Effective
Date		Form Security Class ID Avg Price
Paid (Est)		 Reported
Shares		 ΔShares ΔShares
(%)		 Reported
Value
(x1000)		 ΔValue
(%)		 Alloc
(%)		 ΔAlloc ΔAlloc (%) Cost Basis
(x1000)		 Unrealized
Gain/Loss
(x1000)
2026-05-15 2026-03-31 13F RAMBUS INC DEL COM 750917106 267,189 -1,633,119 -85.94 24,552 -85.94 0.0080
2026-02-17 2025-12-31 13F RAMBUS INC DEL COM 750917106 1,900,308 78,278 4.30 174,619 -8.03 0.0551
2025-11-14 2025-09-30 13F RAMBUS INC DEL COM 750917106 1,822,030 1,551,159 572.66 189,856 994.83 0.0598
2025-08-14 2025-06-30 13F RAMBUS INC DEL COM 750917106 270,871 43,073 18.91 17,341 47.03 0.0057
2025-05-15 2025-03-31 13F RAMBUS INC DEL COM 750917106 227,798 -5,838 -2.50 11,794 -4.49 0.0043
2025-02-12 2024-12-31 13F RAMBUS INC DEL COM 750917106 233,636 -2,817 -1.19 12,350 23.70 0.0042
2024-11-14 2024-09-30 13F RAMBUS INC DEL COM 750917106 236,453 -21,926 -8.49 9,983 -34.24 0.0034
2024-08-14 2024-06-30 13F RAMBUS INC DEL COM 750917106 258,379 -9,638 -3.60 15,182 -8.35 0.0053
2024-05-14 2024-03-31 13F RAMBUS INC DEL COM 750917106 268,017 22,714 9.26 16,566 -1.05 0.0059
2024-02-14 2023-12-31 13F RAMBUS INC DEL COM 750917106 245,303 95,354 63.59 16,742 100.13 0.0064
2023-11-14 2023-09-30 13F RAMBUS INC DEL COM 750917106 149,949 -52 -0.03 8,366 -13.09 0.0036
2023-08-15 2023-06-30 13F RAMBUS INC DEL COM 750917106 150,001 3,069 2.09 9,626 27.81 0.0039
2023-05-15 2023-03-31 13F RAMBUS INC DEL COM 750917106 146,932 -20,348 -12.16 7,532 25.71 0.0032
2023-02-15 2022-12-31 13F RAMBUS INC DEL COM 750917106 167,280 14,231 9.30 5,992 53.97 0.0027
2022-11-15 2022-09-30 13F RAMBUS INC DEL COM 750917106 153,049 322 0.21 3,891 18.56 0.0019
2022-08-15 2022-06-30 13F RAMBUS INC DEL COM 750917106 152,727 2,115 1.40 3,282 -31.67 0.0015
2022-05-13 2022-03-31 13F RAMBUS INC DEL COM 750917106 150,612 -7,842 -4.95 4,803 3.14 0.0019
2022-02-14 2021-12-31 13F RAMBUS INC DEL COM 750917106 158,454 -6,304 -3.83 4,657 27.31 0.0016
2021-11-10 2021-09-30 13F RAMBUS INC DEL COM 750917106 164,758 -11,970 -6.77 3,658 -12.70 0.0014
2021-07-30 2021-06-30 13F RAMBUS INC DEL COM 750917106 176,728 17,260 10.82 4,190 35.16 0.0017
2021-05-06 2021-03-31 13F RAMBUS INC DEL COM 750917106 159,468 -18,910 -10.60 3,100 -0.45 0.0014
2021-02-08 2020-12-31 13F RAMBUS INC DEL COM 750917106 178,378 -250 -0.14 3,114 27.36 0.0015
2020-11-12 2020-09-30 13F RAMBUS INC DEL COM 750917106 178,628 -1,420 -0.79 2,445 -10.67 0.0013
2020-08-13 2020-06-30 13F RAMBUS INC DEL COM 750917106 180,048 21,304 13.42 2,737 55.33 0.0016
2020-05-14 2020-03-31 13F RAMBUS INC DEL COM 750917106 158,744 350 0.22 1,762 -19.25 0.0013
2020-02-18 2019-12-31 13F RAMBUS INC DEL COM 750917106 158,394 3,918 2.54 2,182 7.65 0.0012
2019-11-14 2019-09-30 13F RAMBUS INC DEL COM 750917106 154,476 -25,150 -14.00 2,027 -6.29 0.0013
2019-08-14 2019-06-30 13F RAMBUS INC DEL COM 750917106 179,626 44,650 33.08 2,163 53.40 0.0013
2019-05-14 2019-03-31 13F RAMBUS INC DEL COM 750917106 134,976 -104 -0.08 1,410 36.10 0.0009
2019-02-13 2018-12-31 13F RAMBUS INC DEL COM 750917106 135,080 5,200 4.00 1,036 -26.89 0.0008
2018-11-08 2018-09-30 13F RAMBUS INC DEL COM 750917106 129,880 -6,800 -4.98 1,417 -17.33 0.0009
2018-08-13 2018-06-30 13F RAMBUS INC DEL COM 750917106 136,680 -30,023 -18.01 1,714 -23.45 0.0012
2018-05-14 2018-03-31 13F RAMBUS INC DEL COM 750917106 166,703 2,983 1.82 2,239 -3.82 0.0016
2018-02-13 2017-12-31 13F RAMBUS INC DEL COM 750917106 163,720 -15,400 -8.60 2,328 -2.63 0.0017
2017-11-13 2017-09-30 13F RAMBUS INC DEL COM 750917106 179,120 0 0.00 2,391 16.81 0.0018
2017-08-10 2017-06-30 13F RAMBUS INC DEL COM 750917106 179,120 -15,400 -7.92 2,047 -19.91 0.0016
2017-05-11 2017-03-31 13F RAMBUS INC DEL COM 750917106 194,520 0 0.00 2,556 -4.59 0.0020
2017-02-13 2016-12-31 13F RAMBUS INC DEL COM 750917106 194,520 0 0.00 2,679 10.16 0.0022
2016-11-10 2016-09-30 13F RAMBUS INC DEL COM 750917106 194,520 -6,300 -3.14 2,432 0.25 0.0021
2016-08-11 2016-06-30 13F RAMBUS INC DEL COM 750917106 200,820 -3,800 -1.86 2,426 -13.79 0.0021
2016-05-13 2016-03-31 13F RAMBUS INC DEL COM 750917106 204,620 -5,600 -2.66 2,814 15.52 0.0024
2016-02-16 2015-12-31 13F/A-1 RAMBUS INC DEL COM 750917106 210,220 0 0.00 2,436 -1.81 0.0021
2016-02-12 2015-12-31 13F RAMBUS INC DEL COM 750917106 210,220 2,481
2015-11-13 2015-09-30 13F RAMBUS INC DEL COM 750917106 210,220 -8,520 -3.90 2,481 -21.74 0.0021
2015-08-14 2015-06-30 13F RAMBUS INC DEL COM 750917106 218,740 0 0.00 3,170 15.23 0.0026
2015-05-13 2015-03-31 13F RAMBUS COM 750917106 218,740 -4,500 -2.02 2,751 11.11 0.0022
2015-02-13 2014-12-31 13F RAMBUS COM 750917106 223,240 0 0.00 2,476 -11.13 0.0021
2014-11-13 2014-09-30 13F RAMBUS COM 750917106 223,240 0 0.00 2,786 -12.72 0.0023
2014-08-13 2014-06-30 13F RAMBUS COM 750917106 223,240 24,100 12.10 3,192 49.09 0.0027
2014-05-13 2014-03-31 13F RAMBUS COM 750917106 199,140 -5 -0.00 2,141 13.52 0.0018
2014-02-13 2013-12-31 13F RAMBUS COM 750917106 199,145 -8,495 -4.09 1,886 -3.38 0.0017
2013-11-14 2013-09-30 13F RAMBUS COM 750917106 207,640 -1,556 -0.74 1,952 8.63 0.0019
2013-08-13 2013-06-30 13F RAMBUS COM 750917106 209,196 209,196 1,797 0.0019
Legend
Shares
The total number of shares held by the institution at the end of the reporting period (the effective date). This is provided in the filing.
Value
The total value of the shares as of the effective date. This is provided in the filing.
Avg. Share Price
The weighted average share price of the shares held by the institution. We use FIFO accounting to determine this price
Class
This is the security class as indicated by the filer. There are a variety of values for this field. Common values include "EC" = equity common, "EP" - equity preferred
Allocation (%)
The percent of the institution's portfolio that this position represents. This is provided in NPORT filings. For 13F filings, we calculate it.
Change in Allocation
The change in allocation from the prior reporting period. This is calculated as current allocation - prior allocation.
Change in Allocation (%)
The percent change in allocation from the prior reporting period. This is calculated as (current allocation - prior allocation) / prior allocation.
Cost Basis
The total cost of the shares held. This is calculated as reported shares * avg. share price
Unrealized Gain/Loss
This is the market value of the position as of the effective date minus the cost basis.