Martin Marietta Materials, Inc.
MX ˙ BMV ˙ US5732841060
SecurityMX:MLM / Martin Marietta Materials, Inc.
InstitutionBrown Advisory Inc
Latest Disclosed Ownership9,817 shares
Latest Disclosed Value $ 5,779,357
Brown Advisory Inc reports 10.98% decrease in ownership of MLM / Martin Marietta Materials, Inc.

On May 15, 2026 - Brown Advisory Inc filed a 13F-HR form disclosing ownership of 9,817 shares of Martin Marietta Materials, Inc. (MX:MLM) valued at $5,779,357 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 13, 2026 disclosing 11,028 shares of Martin Marietta Materials, Inc.. This represents a change in shares of -10.98% during the quarter.

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 MARTIN MARIETTA MATLS COM 573284106 9,817 -1,211 -10.98 5,779 -15.83 0.0042
2026-02-13 2025-12-31 13F MARTIN MARIETTA MATLS COM 573284106 11,028 3,480 46.10 6,867 44.33 0.0096
2025-11-14 2025-09-30 13F MARTIN MARIETTA MATLS COM 573284106 7,548 254 3.48 4,758 18.84 0.0062
2025-08-13 2025-06-30 13F MARTIN MARIETTA MATLS COM 573284106 7,294 702 10.65 4,004 27.04 0.0053
2025-04-30 2025-03-31 13F MARTIN MARIETTA MATLS COM 573284106 6,592 1,252 23.45 3,152 14.25 0.0045
2025-02-14 2024-12-31 13F MARTIN MARIETTA MATLS COM 573284106 5,340 201 3.91 2,758 -0.29 0.0035
2024-11-13 2024-09-30 13F MARTIN MARIETTA MATLS COM 573284106 5,139 1,266 32.69 2,766 31.84 0.0035
2024-08-14 2024-06-30 13F MARTIN MARIETTA MATLS COM 573284106 3,873 492 14.55 2,098 1.11 0.0027
2024-04-24 2024-03-31 13F MARTIN MARIETTA MATLS COM 573284106 3,381 133 4.09 2,076 28.09 0.0028
2024-02-08 2023-12-31 13F MARTIN MARIETTA MATLS COM 573284106 3,248 63 1.98 1,620 23.95 0.0023
2023-10-25 2023-09-30 13F MARTIN MARIETTA MATLS COM 573284106 3,185 -6 -0.19 1,307 -11.27 0.0021
2023-07-31 2023-06-30 13F MARTIN MARIETTA MATLS COM 573284106 3,191 15 0.47 1,473 30.70 0.0023
2023-05-08 2023-03-31 13F MARTIN MARIETTA MATLS COM 573284106 3,176 7 0.22 1,128 5.23 0.0019
2023-02-13 2022-12-31 13F MARTIN MARIETTA MATLS COM 573284106 3,169 10 0.32 1,071 5.21 0.0020
2022-11-14 2022-09-30 13F MARTIN MARIETTA MATLS COM 573284106 3,159 82 2.66 1,018 10.53 0.0020
2022-11-14 2022-06-30 13F/A-2 MARTIN MARIETTA MATLS COM 573284106 3,077 -151 -4.68 921 -25.91 0.0017
2022-09-13 2022-06-30 13F/A-1 MARTIN MARIETTA MATLS COM 573284106 2,833 -786 848 0.0015
2022-08-02 2022-06-30 13F MARTIN MARIETTA MATLS COM 573284106 2,833 -151 848 0.0014
2022-11-14 2022-03-31 13F/A-2 MARTIN MARIETTA MATLS COM 573284106 3,228 198 6.53 1,243 -6.82 0.0019
2022-09-13 2022-03-31 13F/A-1 MARTIN MARIETTA MATLS COM 573284106 3,619 589 1,393 0.0020
2022-05-09 2022-03-31 13F MARTIN MARIETTA MATLS COM 573284106 2,984 -46 1,149 0.0016
2022-01-27 2021-12-31 13F MARTIN MARIETTA MATLS COM 573284106 3,030 -196 -6.08 1,334 21.05 0.0017
2021-11-12 2021-09-30 13F MARTIN MARIETTA MATLS COM 573284106 3,226 161 5.25 1,102 2.23 0.0016
2021-07-29 2021-06-30 13F MARTIN MARIETTA MATLS COM 573284106 3,065 126 4.29 1,078 9.22 0.0016
2021-05-14 2021-03-31 13F MARTIN MARIETTA MATLS COM 573284106 2,939 18 0.62 987 19.06 0.0017
2021-02-12 2020-12-31 13F MARTIN MARIETTA MATLS COM 573284106 2,921 -1 -0.03 829 20.67 0.0015
2020-11-16 2020-09-30 13F MARTIN MARIETTA MATLS COM 573284106 2,922 -21 -0.71 687 13.18 0.0014
2020-08-14 2020-06-30 13F MARTIN MARIETTA MATLS COM 573284106 2,943 -1,135 -27.83 607 -21.37 0.0014
2020-05-15 2020-03-31 13F MARTIN MARIETTA MATLS COM 573284106 4,078 -18 -0.44 772 -32.58 0.0024
2020-02-14 2019-12-31 13F MARTIN MARIETTA MATLS COM 573284106 4,096 424 11.55 1,145 13.82 0.0029
2019-11-14 2019-09-30 13F MARTIN MARIETTA MATLS COM 573284106 3,672 -10 -0.27 1,006 18.63 0.0028
2019-08-12 2019-06-30 13F MARTIN MARIETTA MATLS COM 573284106 3,682 -528 -12.54 848 0.12 0.0024
2019-05-15 2019-03-31 13F MARTIN MARIETTA MATLS COM 573284106 4,210 107 2.61 847 20.14 0.0024
2019-02-13 2018-12-31 13F MARTIN MARIETTA MATLS COM 573284106 4,103 0 0.00 705 -5.50 0.0024
2018-11-13 2018-09-30 13F MARTIN MARIETTA MATLS COM 573284106 4,103 31 0.76 746 -18.02 0.0021
2018-08-10 2018-06-30 13F MARTIN MARIETTA MATLS COM 573284106 4,072 -1 -0.02 910 7.69 0.0028
2018-06-28 2018-03-31 13F/A-1 MARTIN MARIETTA MATLS COM 573284106 4,073 -14,145 -77.64 845 -79.01 0.0027
2018-05-14 2018-03-31 13F MARTIN MARIETTA MATLS COM 573284106 3,837 -14,381 795
2018-02-12 2017-12-31 13F MARTIN MARIETTA MATLS COM 573284106 18,218 1,227 7.22 4,026 14.90 0.0127
2017-11-13 2017-09-30 13F MARTIN MARIETTA MATLS COM 573284106 16,991 1,876 12.41 3,504 4.16 0.0116
2017-08-14 2017-06-30 13F MARTIN MARIETTA MATLS COM 573284106 15,115 995 7.05 3,364 9.11 0.0103
2017-05-15 2017-03-31 13F MARTIN MARIETTA MATLS COM 573284106 14,120 1,670 13.41 3,083 11.78 0.0105
2017-02-13 2016-12-31 13F MARTIN MARIETTA MATLS COM 573284106 12,450 1,127 9.95 2,758 36.00 0.0098
2016-11-14 2016-09-30 13F MARTIN MARIETTA MATLS COM 573284106 11,323 5,034 80.04 2,028 67.88 0.0070
2016-08-09 2016-06-30 13F MARTIN MARIETTA MATLS COM 573284106 6,289 2,973 89.66 1,208 128.36 0.0042
2016-05-13 2016-03-31 13F MARTIN MARIETTA MATLS COM 573284106 3,316 -246 -6.91 529 8.62 0.0018
2016-02-08 2015-12-31 13F MARTIN MARIETTA MATLS COM 573284106 3,562 -185 -4.94 487 -14.56 0.0017
2015-11-13 2015-09-30 13F MARTIN MARIETTA MATLS COM 573284106 3,747 1,595 74.12 570 86.89 0.0020
2015-08-11 2015-06-30 13F MARTIN MARIETTA MATLS COM 573284106 2,152 -1,029 -32.35 305 -31.46 0.0010
2015-05-14 2015-03-31 13F MARTIN MARIETTA MATLS COM 573284106 3,181 3,181 445 0.0014
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.