Rambus Inc.
US ˙ NasdaqGS ˙ US7509171069

SecurityRMBS / Rambus Inc.
InstitutionMorgan Stanley
Latest Disclosed Ownership1,213,197 shares
Latest Disclosed Value $ 104,371,458
Morgan Stanley reports 37.07% increase in ownership of RMBS / Rambus Inc.

On May 15, 2026 - Morgan Stanley filed a 13F-HR form disclosing ownership of 1,213,197 shares of Rambus Inc. (US:RMBS) valued at $104,371,338 USD as of March 31, 2026. The entity filed a previous 13F-HR/A on May 27, 2026 disclosing 885,092 shares of Rambus Inc.. This represents a change in shares of 37.07% during the quarter. The current value of the position is $205,454,912 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.

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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 1,213,197 328,105 37.07 104,371 28.33 0.0063
2026-05-27 2025-12-31 13F/A-1 RAMBUS INC DEL COM 750917106 885,092 -180,712 -16.96 81,331 -26.77 0.0049
2026-02-13 2025-12-31 13F RAMBUS INC DEL COM 750917106 885,092 -180,712 81,331 0.0049
2026-05-27 2025-09-30 13F/A-1 RAMBUS INC DEL COM 750917106 1,065,804 -97,455 -8.38 111,057 49.13 0.0067
2025-11-14 2025-09-30 13F RAMBUS INC DEL COM 750917106 1,065,804 -97,455 111,057 0.0067
2025-08-15 2025-06-30 13F RAMBUS INC DEL COM 750917106 1,163,259 225,227 24.01 74,472 53.34 0.0049
2025-05-15 2025-03-31 13F RAMBUS INC DEL COM 750917106 938,032 23,282 2.55 48,567 0.44 0.0035
2025-05-15 2024-12-31 13F/A-1 RAMBUS INC DEL COM 750917106 914,750 -676,027 -42.50 48,354 -28.01 0.0034
2025-02-14 2024-12-31 13F RAMBUS INC DEL COM 750917106 914,750 -676,027 48,354 0.0034
2025-05-14 2024-09-30 13F/A-2 RAMBUS INC DEL COM 750917106 1,590,777 764,545 92.53 67,163 38.34 0.0049
2025-02-14 2024-09-30 13F/A-1 RAMBUS INC DEL COM 750917106 1,590,777 764,545 67,163 0.0049
2024-11-14 2024-09-30 13F RAMBUS INC DEL COM 750917106 1,590,777 764,545 67,163 0.0006
2025-05-14 2024-06-30 13F/A-2 RAMBUS INC DEL COM 750917106 826,232 10,089 1.24 48,549 -3.76 0.0038
2024-10-17 2024-06-30 13F/A-1 RAMBUS INC DEL COM 750917106 826,232 10,089 48,549 0.0038
2024-08-14 2024-06-30 13F RAMBUS INC DEL COM 750917106 826,232 10,089 48,549 0.0038
2024-10-17 2024-03-31 13F/A-2 RAMBUS INC DEL COM 750917106 816,143 -154,246 -15.90 50,446 -23.83 0.0040
2024-08-16 2024-03-31 13F/A-1 RAMBUS INC DEL COM 750917106 816,143 -154,246 50,446 0.0040
2024-05-15 2024-03-31 13F RAMBUS INC DEL COM 750917106 816,143 -154,246 50,446 0.0040
2024-08-16 2023-12-31 13F/A-1 RAMBUS INC DEL COM 750917106 970,389 -79,648 -7.59 66,229 13.06 0.0058
2024-02-13 2023-12-31 13F RAMBUS INC DEL COM 750917106 970,389 -79,648 66,229 0.0058
2023-11-15 2023-09-30 13F RAMBUS INC DEL COM 750917106 1,050,037 -458,307 -30.38 58,582 -39.48 0.0060
2023-08-14 2023-06-30 13F RAMBUS INC DEL COM 750917106 1,508,344 525,224 53.42 96,790 92.07 0.0095
2023-05-15 2023-03-31 13F RAMBUS INC DEL COM 750917106 983,120 -48,939 -4.74 50,395 36.32 0.0054
2023-02-14 2022-12-31 13F RAMBUS INC DEL COM 750917106 1,032,059 35,230 3.53 36,968 45.89 0.0042
2022-11-14 2022-09-30 13F RAMBUS INC DEL COM 750917106 996,829 -31,903 -3.10 25,339 14.62 0.0035
2022-10-27 2022-06-30 13F/A-1 RAMBUS INC DEL COM 750917106 1,028,732 306,508 42.44 22,107 -4.02 0.0029
2022-08-15 2022-06-30 13F RAMBUS INC DEL COM 750917106 1,028,732 306,508 22,107 0.0006
2022-10-27 2022-03-31 13F/A-1 RAMBUS INC DEL COM 750917106 722,224 -121,268 -14.38 23,032 -7.09 0.0031
2022-05-13 2022-03-31 13F RAMBUS INC DEL COM 750917106 722,224 -121,268 23,032 0.0031
2022-02-14 2021-12-31 13F RAMBUS INC DEL COM 750917106 843,492 273,517 47.99 24,790 95.91 0.0031
2021-11-15 2021-09-30 13F RAMBUS INC DEL COM 750917106 569,975 91,346 19.08 12,654 11.50 0.0017
2021-08-23 2021-06-30 13F/A-1 RAMBUS INC DEL COM 750917106 478,629 118,665 32.97 11,349 62.20 0.0015
2021-08-16 2021-06-30 13F RAMBUS INC DEL COM 750917106 478,629 118,665 11,349 0.0003
2021-05-17 2021-03-31 13F RAMBUS INC DEL COM 750917106 359,964 -165,325 -31.47 6,997 -23.71 0.0010
2021-02-16 2020-12-31 13F RAMBUS INC DEL COM 750917106 525,289 222,650 73.57 9,172 121.39 0.0014
2020-11-13 2020-09-30 13F RAMBUS INC DEL COM 750917106 302,639 -25,756 -7.84 4,143 -16.99 0.0008
2020-08-14 2020-06-30 13F RAMBUS INC DEL COM 750917106 328,395 13,543 4.30 4,991 42.80 0.0011
2020-05-26 2020-03-31 13F/A-1 RAMBUS INC DEL COM 750917106 314,852 -800,677 -71.78 3,495 -77.26 0.0009
2020-05-15 2020-03-31 13F RAMBUS INC DEL COM 750917106 314,852 -800,677 3,495 268.4889
2020-02-14 2019-12-31 13F RAMBUS INC DEL COM 750917106 1,115,529 350,040 45.73 15,367 52.94 0.0036
2019-11-14 2019-09-30 13F RAMBUS INC DEL COM 750917106 765,489 -415,167 -35.16 10,048 -29.31 0.0027
2019-08-14 2019-06-30 13F RAMBUS INC DEL COM 750917106 1,180,656 1,152,710 4,124.78 14,215 4,768.15 0.0038
2019-05-15 2019-03-31 13F RAMBUS INC DEL COM 750917106 27,946 -2,111,921 -98.69 292 -98.22 0.0001
2019-02-14 2018-12-31 13F RAMBUS INC DEL COM 750917106 2,139,867 1,434,922 203.55 16,414 113.45 0.0049
2019-04-23 2018-09-30 13F/A-2 RAMBUS INC DEL COM 750917106 704,945 -66,009 -8.56 7,690 -20.46 0.0019
2018-11-20 2018-09-30 13F/A-1 RAMBUS INC DEL COM 750917106 704,945 0 7,690 0.0019
2018-11-14 2018-09-30 13F RAMBUS INC DEL COM 750917106 704,945 -66,009 7,690
2019-04-23 2018-06-30 13F/A-1 RAMBUS INC DEL COM 750917106 770,954 -257,476 -25.04 9,668 -30.00 0.0026
2018-08-14 2018-06-30 13F RAMBUS INC DEL COM 750917106 770,954 -257,476 9,668
2019-04-23 2018-03-31 13F/A-1 RAMBUS INC DEL COM 750917106 1,028,430 -393,485 -27.67 13,811 -31.69 0.0038
2018-05-14 2018-03-31 13F RAMBUS INC DEL COM 750917106 1,028,430 -393,485 13,811
2019-04-23 2017-12-31 13F/A-1 RAMBUS INC DEL COM 750917106 1,421,915 573,854 67.67 20,219 78.58 0.0055
2018-02-14 2017-12-31 13F RAMBUS INC DEL COM 750917106 1,421,915 573,854 20,219
2017-11-14 2017-09-30 13F RAMBUS INC DEL COM 750917106 848,061 -54,838 -6.07 11,322 9.71 0.0034
2017-08-11 2017-06-30 13F RAMBUS INC DEL COM 750917106 902,899 121,135 15.50 10,320 0.47 0.0031
2017-05-22 2017-03-31 13F/A-1 RAMBUS INC DEL COM 750917106 781,764 -112,825 -12.61 10,272 -16.62 0.0032
2017-05-12 2017-03-31 13F RAMBUS INC DEL COM 750917106 781,764 10,272
2017-02-22 2016-12-31 13F/A-1 RAMBUS INC DEL COM 750917106 894,589 163,172 22.31 12,319 34.72 0.0040
2017-02-13 2016-12-31 13F RAMBUS INC DEL COM 750917106 894,589 12,319
2016-11-10 2016-09-30 13F RAMBUS INC DEL COM 750917106 731,417 636,517 670.72 9,144 697.91 0.0031
2016-08-12 2016-06-30 13F RAMBUS INC DEL COM 750917106 94,900 -78,241 -45.19 1,146 -51.87 0.0004
2016-05-12 2016-03-31 13F RAMBUS INC DEL COM 750917106 173,141 -1,518,642 -89.77 2,381 -87.86 0.0009
2016-02-09 2015-12-31 13F RAMBUS INC DEL COM 750917106 1,691,783 1,484,567 716.43 19,607 702.25 0.0071
2016-02-08 2015-09-30 13F/A-1 RAMBUS INC DEL COM 750917106 207,216 46,476 28.91 2,444 4.94 0.0009
2015-11-09 2015-09-30 13F RAMBUS INC DEL COM 750917106 207,216 2,444
2015-08-12 2015-06-30 13F RAMBUS INC DEL COM 750917106 160,740 17,449 12.18 2,329 29.25 0.0008
2015-05-14 2015-03-31 13F RAMBUS INC DEL COM 750917106 143,291 -125,124 -46.62 1,802 -39.47 0.0007
2015-02-13 2014-12-31 13F RAMBUS INC DEL COM 750917106 268,415 150,897 128.40 2,977 103.07 0.0011
2014-12-16 2014-09-30 13F/A-1 RAMBUS INC DEL COM 750917106 117,518 -28,569 -19.56 1,466 -6.68 0.0006
2014-11-14 2014-09-30 13F RAMBUS INC DEL COM 750917106 117,518 1,466
2014-05-13 2014-03-31 13F RAMBUS INC DEL COM 750917106 146,087 -4,983 -3.30 1,571 9.78 0.0007
2014-02-13 2013-12-31 13F RAMBUS INC DEL COM 750917106 151,070 103,833 219.81 1,431 222.30 0.0006
2013-11-13 2013-09-30 13F RAMBUS INC DEL COM ST COM 750917106 47,237 -7,645 -13.93 444 -5.93 0.0002
2013-08-08 2013-06-30 13F RAMBUS INC DEL COM ST COM 750917106 54,882 54,882 472 0.0002
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.