Martin Marietta Materials, Inc.
US ˙ NYSE ˙ US5732841060

SecurityMLM / Martin Marietta Materials, Inc.
InstitutionCwm, Llc
Latest Disclosed Ownership4,428 shares
Latest Disclosed Value $ 2,606,452
Cwm, Llc reports 22.11% decrease in ownership of MLM / Martin Marietta Materials, Inc.

On May 14, 2026 - Cwm, Llc filed a 13F-HR form disclosing ownership of 4,428 shares of Martin Marietta Materials, Inc. (US:MLM) valued at $2,606,675 USD as of March 31, 2026. The entity filed a previous 13F-HR on January 26, 2026 disclosing 5,685 shares of Martin Marietta Materials, Inc.. This represents a change in shares of -22.11% during the quarter. The current value of the position is $2,582,188 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)
2026-05-14 2026-03-31 13F MARTIN MARIETTA MATLS COM 573284106 4,428 -1,257 -22.11 2,606 86,766.67 0.0068
2026-01-26 2025-12-31 13F MARTIN MARIETTA MATLS COM 573284106 5,685 -620 -9.83 4 0.00 0.0096
2025-10-15 2025-09-30 13F MARTIN MARIETTA MATLS COM 573284106 6,305 2,575 69.03 4 50.00 0.0120
2025-07-25 2025-06-30 13F MARTIN MARIETTA MATLS COM 573284106 3,730 578 18.34 2 100.00 0.0072
2025-05-01 2025-03-31 13F MARTIN MARIETTA MATLS COM 573284106 3,152 1,250 65.72 2 0.0060
2025-02-04 2024-12-31 13F MARTIN MARIETTA MATLS COM 573284106 1,902 153 8.75 1 0.0041
2024-10-08 2024-09-30 13F MARTIN MARIETTA MATLS COM 573284106 1,749 114 6.97 1 0.0041
2024-07-10 2024-06-30 13F MARTIN MARIETTA MATLS COM 573284106 1,635 -50 -2.97 1 -100.00 0.0042
2024-04-05 2024-03-31 13F MARTIN MARIETTA MATLS COM 573284106 1,685 161 10.56 1 0.0050
2024-02-01 2023-12-31 13F MARTIN MARIETTA MATLS COM 573284106 1,524 46 3.11 1 0.0041
2023-10-11 2023-09-30 13F MARTIN MARIETTA MATLS COM 573284106 1,478 31 2.14 1 0.0037
2023-08-03 2023-06-30 13F MARTIN MARIETTA MATLS COM 573284106 1,447 109 8.15 1 0.0041
2023-05-01 2023-03-31 13F MARTIN MARIETTA MATLS COM 573284106 1,338 417 45.28 0 0.0032
2023-02-01 2022-12-31 13F MARTIN MARIETTA MATLS COM 573284106 921 63 7.34 0 -100.00 0.0023
2022-10-27 2022-09-30 13F MARTIN MARIETTA MATLS COM 573284106 858 152 21.53 276 30.81 0.0022
2022-07-28 2022-06-30 13F MARTIN MARIETTA MATLS COM 573284106 706 67 10.49 211 -14.23 0.0016
2022-04-21 2022-03-31 13F MARTIN MARIETTA MATLS COM 573284106 639 170 36.25 246 18.84 0.0017
2022-01-31 2021-12-31 13F MARTIN MARIETTA MATLS COM 573284106 469 -703 -59.98 207 -49.76 0.0015
2021-09-15 2021-06-30 13F/A-1 MARTIN MARIETTA MATLS COM 573284106 1,172 0 0.00 412 0.00 0.0033
2021-07-29 2021-06-30 13F MARTIN MARIETTA MATLS COM 573284106 1,172 0 412 0.0033
2021-09-15 2021-03-31 13F/A-1 MARTIN MARIETTA MATLS COM 573284106 1,172 0 0.00 412 0.00 0.0033
2021-04-27 2021-03-31 13F MARTIN MARIETTA MATLS COM 573284106 593 -579 199 0.0018
2021-09-15 2020-12-31 13F/A-1 MARTIN MARIETTA MATLS COM 573284106 1,172 0 0.00 412 0.00 0.0033
2021-01-27 2020-12-31 13F MARTIN MARIETTA MATLS COM 573284106 332 -840 94 0.0009
2021-09-15 2020-09-30 13F/A-1 MARTIN MARIETTA MATLS COM 573284106 1,172 0 0.00 412 0.00 0.0033
2020-10-19 2020-09-30 13F MARTIN MARIETTA MATLS COM 573284106 332 -840 78 0.0009
2021-09-15 2020-06-30 13F/A-1 MARTIN MARIETTA MATLS COM 573284106 1,172 0 0.00 412 0.00 0.0033
2020-07-22 2020-06-30 13F MARTIN MARIETTA MATLS COM 573284106 311 -861 64 0.0008
2021-09-15 2020-03-31 13F/A-1 MARTIN MARIETTA MATLS COM 573284106 1,172 0 0.00 412 0.00 0.0033
2020-04-28 2020-03-31 13F MARTIN MARIETTA MATLS COM 573284106 320 -852 61 0.0009
2021-09-14 2019-12-31 13F/A-1 MARTIN MARIETTA MATLS COM 573284106 1,172 0 0.00 412 0.00 0.0033
2020-01-27 2019-12-31 13F MARTIN MARIETTA MATLS COM 573284106 353 -819 99 0.0013
2021-09-14 2019-09-30 13F/A-1 MARTIN MARIETTA MATLS COM 573284106 1,172 0 0.00 412 0.00 0.0033
2019-10-22 2019-09-30 13F MARTIN MARIETTA MATLS COM 573284106 351 -821 96 0.0014
2021-09-14 2019-06-30 13F/A-1 MARTIN MARIETTA MATLS COM 573284106 1,172 0 0.00 412 0.00 0.0033
2019-07-31 2019-06-30 13F MARTIN MARIETTA MATLS COM 573284106 310 -862 71 0.0012
2021-09-02 2019-03-31 13F/A-1 MARTIN MARIETTA MATLS COM 573284106 1,172 1,041 794.66 412 1,691.30 0.0033
2019-04-22 2019-03-31 13F MARTIN MARIETTA MATLS COM 573284106 253 122 51 0.0010
2019-01-25 2018-12-31 13F MARTIN MARIETTA MATLS COM 573284106 131 114 670.59 23 666.67 0.0006
2018-10-29 2018-09-30 13F MARTIN MARIETTA MATLS COM 573284106 17 12 240.00 3 200.00 0.0001
2018-07-31 2018-06-30 13F MARTIN MARIETTA MATLS COM 573284106 5 -3 -37.50 1 -50.00 0.0000
2018-04-26 2018-03-31 13F MARTIN MARIETTA MATLS COM 573284106 8 3 60.00 2 100.00 0.0001
2018-01-16 2017-12-31 13F MARTIN MARIETTA MATLS COM 573284106 5 -35 -87.50 1 -87.50 0.0000
2017-10-16 2017-09-30 13F MARTIN MARIETTA MATLS COM 573284106 40 35 700.00 8 700.00 0.0004
2017-07-17 2017-06-30 13F MARTIN MARIETTA MATLS COM 573284106 5 0 0.00 1 0.00 0.0001
2017-04-17 2017-03-31 13F MARTIN MARIETTA MATLS COM 573284106 5 5 1 0.0001
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.