Martin Marietta Materials, Inc.
MX ˙ BMV ˙ US5732841060
SecurityMX:MLM / Martin Marietta Materials, Inc.
InstitutionWeitz Investment Management, Inc.
Latest Disclosed Ownership39,775 shares
Latest Disclosed Value $ 23,414,747
Weitz Investment Management, Inc. reports 3.63% decrease in ownership of MLM / Martin Marietta Materials, Inc.

On May 14, 2026 - Weitz Investment Management, Inc. filed a 13F-HR form disclosing ownership of 39,775 shares of Martin Marietta Materials, Inc. (MX:MLM) valued at $23,414,747 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 12, 2026 disclosing 41,275 shares of Martin Marietta Materials, Inc.. This represents a change in shares of -3.63% 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)
2026-05-14 2026-03-31 13F MARTIN MARIETTA MATLS COM 573284106 39,775 -1,500 -3.63 23,415 -8.89 1.6345
2026-02-12 2025-12-31 13F MARTIN MARIETTA MATLS COM 573284106 41,275 0 0.00 25,700 -1.21 1.5238
2025-11-10 2025-09-30 13F MARTIN MARIETTA MATLS COM 573284106 41,275 0 0.00 26,015 14.81 1.4117
2025-08-12 2025-06-30 13F MARTIN MARIETTA MATLS COM 573284106 41,275 0 0.00 22,658 14.82 1.2184
2025-05-09 2025-03-31 13F MARTIN MARIETTA MATLS COM 573284106 41,275 600 1.48 19,735 -6.06 1.0484
2025-02-12 2024-12-31 13F MARTIN MARIETTA MATLS COM 573284106 40,675 0 0.00 21,009 -4.04 1.0834
2024-11-12 2024-09-30 13F MARTIN MARIETTA MATLS COM 573284106 40,675 0 0.00 21,893 -0.65 1.0793
2024-08-14 2024-06-30 13F MARTIN MARIETTA MATLS COM 573284106 40,675 0 0.00 22,038 -11.75 1.1565
2024-05-13 2024-03-31 13F MARTIN MARIETTA MATLS COM 573284106 40,675 -8,625 -17.49 24,972 1.53 1.2605
2024-02-12 2023-12-31 13F MARTIN MARIETTA MATLS COM 573284106 49,300 -12,700 -20.48 24,596 -3.35 1.2962
2023-11-13 2023-09-30 13F MARTIN MARIETTA MATLS COM 573284106 62,000 -4,100 -6.20 25,450 -16.61 1.3996
2023-08-10 2023-06-30 13F MARTIN MARIETTA MATLS COM 573284106 66,100 -450 -0.68 30,518 29.15 1.6265
2023-05-12 2023-03-31 13F MARTIN MARIETTA MATLS COM 573284106 66,550 500 0.76 23,629 5.86 1.3619
2023-02-09 2022-12-31 13F MARTIN MARIETTA MATLS COM 573284106 66,050 -3,000 -4.34 22,323 0.37 1.2652
2022-11-09 2022-09-30 13F MARTIN MARIETTA MATLS COM 573284106 69,050 0 0.00 22,240 7.63 1.3086
2022-08-12 2022-06-30 13F MARTIN MARIETTA MATLS COM 573284106 69,050 1,800 2.68 20,663 -20.17 1.0799
2022-05-13 2022-03-31 13F MARTIN MARIETTA MATLS COM 573284106 67,250 1,068 1.61 25,884 -11.22 1.1467
2022-02-11 2021-12-31 13F MARTIN MARIETTA MATLS COM 573284106 66,182 -4,268 -6.06 29,154 21.12 1.1695
2021-11-15 2021-09-30 13F MARTIN MARIETTA MATLS COM 573284106 70,450 0 0.00 24,071 -2.88 1.0078
2021-08-10 2021-06-30 13F MARTIN MARIETTA MATLS COM 573284106 70,450 0 0.00 24,785 4.76 1.0457
2021-05-13 2021-03-31 13F MARTIN MARIETTA MATLS COM 573284106 70,450 0 0.00 23,659 18.26 1.0447
2021-02-10 2020-12-31 13F MARTIN MARIETTA MATLS COM 573284106 70,450 0 0.00 20,006 20.66 0.8528
2020-11-12 2020-09-30 13F MARTIN MARIETTA MATLS COM 573284106 70,450 0 0.00 16,581 13.94 0.7768
2020-08-12 2020-06-30 13F MARTIN MARIETTA MATLS COM 573284106 70,450 16,020 29.43 14,553 41.29 0.7225
2020-05-11 2020-03-31 13F MARTIN MARIETTA MATLS COM 573284106 54,430 -9,100 -14.32 10,300 -42.02 0.5465
2020-02-13 2019-12-31 13F MARTIN MARIETTA MATLS COM 573284106 63,530 0 0.00 17,766 2.02 0.6968
2019-11-13 2019-09-30 13F MARTIN MARIETTA MATLS COM 573284106 63,530 -2,500 -3.79 17,414 14.61 0.7074
2019-08-08 2019-06-30 13F MARTIN MARIETTA MATLS COM 573284106 66,030 0 0.00 15,194 14.38 0.6029
2019-05-14 2019-03-31 13F MARTIN MARIETTA MATLS COM 573284106 66,030 -1,100 -1.64 13,284 15.13 0.5500
2019-02-11 2018-12-31 13F MARTIN MARIETTA MATLS COM 573284106 67,130 59,630 795.07 11,538 745.27 0.5288
2018-11-13 2018-09-30 13F MARTIN MARIETTA MATLS COM 573284106 7,500 1,000 15.38 1,365 -5.99 0.0556
2018-08-13 2018-06-30 13F MARTIN MARIETTA MATLS COM 573284106 6,500 0 0.00 1,452 7.80 0.0617
2018-05-14 2018-03-31 13F MARTIN MARIETTA MATLS COM 573284106 6,500 0 0.00 1,347 -6.26 0.0569
2018-02-14 2017-12-31 13F MARTIN MARIETTA MATLS COM 573284106 6,500 0 0.00 1,437 7.24 0.0598
2017-11-13 2017-09-30 13F MARTIN MARIETTA MATLS COM 573284106 6,500 6,500 1,340 0.0551
2015-11-13 2015-09-30 13F MARTIN MARIETTA MATLS COM 573284106 0 -700,680 -100.00 0 -100.00
2015-08-14 2015-06-30 13F MARTIN MARIETTA MATLS COM 573284106 700,680 -72,436 -9.37 99,153 -8.26 2.7821
2015-05-12 2015-03-31 13F MARTIN MARIETTA MATLS COM 573284106 773,116 -956 -0.12 108,082 26.57 2.9175
2015-02-12 2014-12-31 13F MARTIN MARIETTA MATLS COM 573284106 774,072 13,809 1.82 85,396 -12.89 2.3843
2014-11-13 2014-09-30 13F MARTIN MARIETTA MATLS COM 573284106 760,263 -13,112 -1.70 98,028 -4.01 2.8841
2014-08-14 2014-06-30 13F MARTIN MARIETTA MATLS COM 573284106 773,375 -23,185 -2.91 102,124 -0.11 3.0841
2014-05-14 2014-03-31 13F MARTIN MARIETTA MATLS COM 573284106 796,560 -82,011 -9.33 102,238 16.44 3.2649
2014-02-13 2013-12-31 13F MARTIN MARIETTA MATLS COM 573284106 878,571 164,901 23.11 87,804 25.33 2.9423
2013-11-13 2013-09-30 13F MARTIN MARIETTA MATLS COM 573284106 713,670 55,070 8.36 70,061 8.09 2.6366
2013-08-08 2013-06-30 13F MARTIN MARIETTA MATLS COM 573284106 658,600 658,600 64,819 2.6236
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.