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Summit Materials, Inc. (SUM) institutional ownership

Market cap$9.2B SectorBasic Materials
Funds holding · Q4 2025
2
reported SUM position changes
Top owners · Q1 2026
No disclosed owners are available.
Institutional activity · Q4 2025
Activity unavailable N/A
0 buyers · 2 sellers

Summit Materials, Inc. (SUM) price and institutional activity

Dates

Q4 2025

$0 bought by 0 investors
$0 sold by 2 investors
Barclays PLCStrengthening Families & Communities, LLC
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Bought Sold Totals per quarter; hover a bar for the names.

Summit Materials, Inc. (SUM) institutional activity · 2

Investor Type Est. change Change Δ Own Date
Barclays PLC · Exited
Change −211K Δ Own −100.0% Date Q4 2025
Barclays PLC Exited· Q4 2025 −211K −100.0% Q4 2025
Strengthening Families & Communities, LLC · Exited
Change −3K Δ Own −100.0% Date Q4 2025
Strengthening Families & Communities, LLC Exited· Q4 2025 −3K −100.0% Q4 2025
Data through Q4 2025 · filed Mar 19, 2026
2 of 2

Famous investor activity in Summit Materials, Inc. (SUM)

Summit Materials, Inc. (SUM) activist and large shareholders

What are Schedules 13D and 13G?

Dates
Owner/Filer identity Shares reported % of shares outstanding Filing date
Argos Sem, LLC 54.7M
% of shares outstanding 31.2% Filing date Nov 25, 2024
Argos Sem, LLC 54.7M 31.2% Nov 25, 2024
BlackRock Inc. 11.4M
% of shares outstanding 9.5% Filing date Jan 24, 2024
BlackRock Inc. 11.4M 9.5% Jan 24, 2024
Vanguard Group Inc 12.3M
% of shares outstanding 7.0% Filing date Nov 12, 2024
Vanguard Group Inc 12.3M 7.0% Nov 12, 2024
Blackrock, Inc. 10.0M
% of shares outstanding 5.7% Filing date Nov 8, 2024
Blackrock, Inc. 10.0M 5.7% Nov 8, 2024
Dimensional Fund Advisors LP 5.5M
% of shares outstanding 4.6% Filing date Feb 9, 2024
Dimensional Fund Advisors LP 5.5M 4.6% Feb 9, 2024
Massachusetts Financial Services Co 7.6M
% of shares outstanding 4.4% Filing date Nov 12, 2024
Massachusetts Financial Services Co 7.6M 4.4% Nov 12, 2024
FMR LLC 4.6M
% of shares outstanding 3.9% Filing date Feb 9, 2023
FMR LLC 4.6M 3.9% Feb 9, 2023
T. Rowe Price Associates, Inc. 5.4M
% of shares outstanding 3.0% Filing date Feb 14, 2025
T. Rowe Price Associates, Inc. 5.4M 3.0% Feb 14, 2025
8 of 9

Summit Materials, Inc. (SUM) ownership FAQ

Who owns SUM?

2 reporting institutions disclosed SUM position changes in the Q4 2025 snapshot.

How is institutional activity calculated?

For each manager, WhoBought compares accepted consecutive 13F share counts. Share change is current shares minus prior shares. Estimated dollar change is that signed share change multiplied by the split-adjusted quarter-mean close. The activity table on this page uses Q4 2025.

What are activist and large shareholder filings?

An investor crossing 5% of a share class generally files Schedule 13D for activist intent or Schedule 13G for a passive position. The technical form names appear here rather than in the activity rows.

Where does this data come from?

Ownership and institutional activity come from SEC Form 13F filings. Insider activity comes from SEC Form 4, and large-shareholder activity from SEC Schedules 13D and 13G. FMP supplies price data only. Company logos use the local verified Parqet cache with one shared fallback.

Why are ownership reports delayed?

Form 13F is a quarterly disclosure and is normally filed after the quarter ends. Every ownership and activity value therefore names its represented period; it is not presented as a live position.

How are missing table values shown?

A muted dash marks a missing table value. It means the filing omitted the value, comparable data is unavailable, or no prior position exists for comparison.