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RMBS in the 13F filings

Rambus Inc Del · CUSIP 750917106

Sector · SemiconductorsTheme · AI infrastructure and semiconductors· L3VLUP-definedTheme · Semiconductors
Quarter
Q3 2026 · early filersQ2 2026Q1 2026Q4 2025Q3 2025Q2 2025Q1 2025Q4 2024Q3 2024Q2 2024Q1 2024Q4 2023
Quarter end
31 Mar 2026
the date the book describes
Filed
27 Oct 2026
latest of these filings; the earliest 12 May 2026
Managers listing it
23
at least, of 95 tracked, among listed positions
Comparable managers
91
filed both Q4 2025 and Q1 2026; 7 listed it in both
Shares listed
18,001,324
combined, among listed positions
Reported value
$1.5bn
combined, at the quarter end

AllianceBernstein LP. Values in this filing are at the previous quarter end's prices; its share count is the quarter end's.

Among the 91 comparable managers: 8 buyers (opened or added shares) and 21 sellers (trimmed or exited), at least, among listed positions. Their net change in shares was +362,532.

Managers listing RMBS in Q1 2026

Share of 13F value is the position’s reported value over everything the manager reported that quarter. The share change is against Q4 2025, and only where both filings list the position. A rise in value with no rise in shares is the price, not buying.

23 of 23 holders

ActionFiling
Invesco Ltd6,499,048$559m0.05%Added+2,350,39512 May 2026 (the filing on sec.gov)
T. Rowe Price Associates Inc3,376,689$290munder 0.1%Trimmed-2,008,88115 May 2026 (the filing on sec.gov)
Fidelity (FMR LLC)3,318,449$285munder 0.1%Added+1,731,42015 May 2026 (the filing on sec.gov)
Neuberger Berman Group LLC1,302,169$112m0.08%Trimmed-3,78227 Oct 2026 (the filing on sec.gov)
AQR Capital Management LLC1,250,456$104munder 0.1%Added+539,33015 May 2026 (the filing on sec.gov)
Wellington Management Group LLP856,598$74munder 0.1%Trimmed-77,33615 May 2026 (the filing on sec.gov)
Janus Henderson Group Ltd358,892$31munder 0.1%Trimmed-20,62318 May 2026 (the filing on sec.gov)
AllianceBernstein LP267,189$25munder 0.1%Trimmed-1,633,11915 May 2026 (the filing on sec.gov)
Steadfast Capital Management LP153,250$13m0.45%Newnew15 May 2026 (the filing on sec.gov)
Millennium Management LLC141,314$12munder 0.1%Trimmed-121,26415 May 2026 (the filing on sec.gov)
Man Group PLC139,132$12munder 0.1%Trimmed-23,80815 May 2026 (the filing on sec.gov)
Susquehanna International Group LLP85,824$7.4munder 0.1%Added+71,99015 May 2026 (the filing on sec.gov)
Two Sigma Investments LP77,410$6.7munder 0.1%Trimmed-66,99315 May 2026 (the filing on sec.gov)
Bridgewater Associates LP51,854$4.5munder 0.1%Trimmed-102,44215 May 2026 (the filing on sec.gov)
Holocene Advisors LP49,604$4.3munder 0.1%Newnew15 May 2026 (the filing on sec.gov)
Acadian Asset Management LLC17,096$1.5munder 0.1%Trimmed-152,32513 May 2026 (the filing on sec.gov)
Citadel Advisors LLC16,495$1.4munder 0.1%Trimmed-153,40715 May 2026 (the filing on sec.gov)
Maverick Capital Ltd13,028$1.1munder 0.1%Newnew15 May 2026 (the filing on sec.gov)
D. E. Shaw & Co.12,805$1.1munder 0.1%Trimmed-5,68615 May 2026 (the filing on sec.gov)
Marshall Wace LLP5,526$475kunder 0.1%Trimmed-10,77415 May 2026 (the filing on sec.gov)
Jane Street Group LLC5,426$467kunder 0.1%Trimmed-2912 May 2026 (the filing on sec.gov)
Winton Group Ltd3,051$262kunder 0.1%Newnew12 May 2026 (the filing on sec.gov)
Walleye Capital LLC19$2kunder 0.1%Trimmed-20,77513 May 2026 (the filing on sec.gov)

Largest increases and reductions, by shares

Q4 2025 to Q1 2026, among managers that listed it in both quarters or opened it.

Increases

Reductions

New positions and exits

At least these many: a manager is shown exiting only where its own filing shows the position gone.

New (4)

Exited (6)

Ownership over time

Every quarter on file. A quarter-end value moves with the price as well as with the shares held; buyers and sellers count comparable managers, by shares.
8 in Q3 2024 to 12 in Q2 2026

Tracked managers listing it, at least.

0510152014201620182020202220242026
the quarter shown share split complete books; unmarked quarters rest on listed positionsClick a quarter to open it.
RMBS by quarter
QuarterHoldersReported valueBuyersSellers
Q2 20131$33kn.a.n.a.
Q1 20142$7.1mn.a.n.a.
Q2 20142$19mn.a.n.a.
Q3 20141$14mn.a.n.a.
Q4 20141$242kn.a.n.a.
Q1 20151$5.0mn.a.n.a.
Q2 20153$65mn.a.n.a.
Q3 20154$61mn.a.n.a.
Q4 20152$64mn.a.n.a.
Q1 20163$76mn.a.n.a.
Q2 20161$44mn.a.n.a.
Q3 20163$47mn.a.n.a.
Q4 20161$49mn.a.n.a.
Q1 20171$48mn.a.n.a.
Q2 20173$44mn.a.n.a.
Q3 20173$95mn.a.n.a.
Q4 20173$109mn.a.n.a.
Q1 20185$106mn.a.n.a.
Q2 20183$95mn.a.n.a.
Q3 20181$1.2mn.a.n.a.
Q4 20182$1.2mn.a.n.a.
Q1 20193$2.7mn.a.n.a.
Q2 20194$90mn.a.n.a.
Q3 20193$97mn.a.n.a.
Q4 20196$121mn.a.n.a.
Q1 20202$83mn.a.n.a.
Q2 20203$109mn.a.n.a.
Q3 20203$92mn.a.n.a.
Q4 20206$116mn.a.n.a.
Q1 20214$109mn.a.n.a.
Q2 20216$133mn.a.n.a.
Q3 20213$105mn.a.n.a.
Q4 20214$118mn.a.n.a.
Q1 20226$163mn.a.n.a.
Q2 20222$109mn.a.n.a.
Q3 20224$142mn.a.n.a.
Q4 20226$227mn.a.n.a.
Q1 20239$464mn.a.n.a.
Q2 20239$319mn.a.n.a.
Q3 20234$279mn.a.n.a.
Q4 20235$574m34
Q1 20244$518m40
Q2 20246$558m33
Q3 20248$174m72
Q4 20245$432m23
Q1 20256$555m42
Q2 20254$403m22
Q3 20256$966m52
Q4 20257$1.2bn198
Q1 20268$1.1bn821
Q2 202612$3.2bn1712

Compare with…

Holders over time, buyers and sellers, and the managers holding both, side by side for up to four stocks.

RMBS and NVDA →RMBS and AVGO →RMBS and MU →Choose a stock to compare with RMBS →

How much of the picture this is

A 13F is a manager’s long US-listed equity book at a quarter end, filed up to 45 days later. It shows no shorts, cash, bonds or performance, and it is never today’s portfolio. Large books are listed to their largest positions, so a manager missing from this table may still hold a small position below that line. These are 95 tracked managers, not the institutional market.

Which funds own RMBS, latest filings →Back to the 13F Explorer →