Martin Marietta Materials, Inc.
MX ˙ BMV ˙ US5732841060
SecurityMX:MLM / Martin Marietta Materials, Inc.
InstitutionNorthwestern Mutual Wealth Management Co
Latest Disclosed Ownership792 shares
Latest Disclosed Value $ 466,287
Northwestern Mutual Wealth Management Co reports 18.03% increase in ownership of MLM / Martin Marietta Materials, Inc.

On May 7, 2026 - Northwestern Mutual Wealth Management Co filed a 13F-HR form disclosing ownership of 792 shares of Martin Marietta Materials, Inc. (MX:MLM) valued at $466,287 USD as of March 31, 2026. The entity filed a previous 13F-HR/A on February 10, 2026 disclosing 671 shares of Martin Marietta Materials, Inc.. This represents a change in shares of 18.03% 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)
2026-05-07 2026-03-31 13F MARTIN MARIETTA MATLS COM 573284106 792 121 18.03 466 11.48 0.0003
2026-02-10 2025-12-31 13F/A-1 MARTIN MARIETTA MATLS COM 573284106 671 132 24.49 418 23.30 0.0003
2026-02-05 2025-12-31 13F MARTIN MARIETTA MATLS COM 573284106 77,792 77,253 4,866 0.0031
2025-11-14 2025-09-30 13F MARTIN MARIETTA MATLS COM 573284106 539 -1,401 -72.22 340 -68.14 0.0002
2025-08-13 2025-06-30 13F MARTIN MARIETTA MATLS COM 573284106 1,940 -245 -11.21 1,065 1.92 0.0008
2025-05-14 2025-03-31 13F MARTIN MARIETTA MATLS COM 573284106 2,185 -374 -14.62 1,045 -20.97 0.0009
2025-02-11 2024-12-31 13F MARTIN MARIETTA MATLS COM 573284106 2,559 756 41.93 1,322 36.19 0.0011
2024-11-12 2024-09-30 13F MARTIN MARIETTA MATLS COM 573284106 1,803 21 1.18 970 0.52 0.0009
2024-08-16 2024-06-30 13F MARTIN MARIETTA MATLS COM 573284106 1,782 339 23.49 965 9.04 0.0010
2024-05-15 2024-03-31 13F MARTIN MARIETTA MATLS COM 573284106 1,443 -221 -13.28 886 6.63 0.0009
2024-02-13 2023-12-31 13F MARTIN MARIETTA MATLS COM 573284106 1,664 71 4.46 830 27.11 0.0009
2023-11-14 2023-09-30 13F MARTIN MARIETTA MATLS COM 573284106 1,593 53 3.44 654 -8.16 0.0008
2023-08-14 2023-06-30 13F MARTIN MARIETTA MATLS COM 573284106 1,540 -55 -3.45 711 25.62 0.0009
2023-05-15 2023-03-31 13F MARTIN MARIETTA MATLS COM 573284106 1,595 -59 -3.57 566 1.25 0.0008
2023-02-21 2022-12-31 13F MARTIN MARIETTA MATLS COM 573284106 1,654 35 2.16 559 7.09 0.0008
2022-11-14 2022-09-30 13F MARTIN MARIETTA MATLS COM 573284106 1,619 -79 -4.65 522 2.76 0.0009
2022-08-04 2022-06-30 13F MARTIN MARIETTA MATLS COM 573284106 1,698 70 4.30 508 -18.98 0.0009
2022-05-09 2022-03-31 13F MARTIN MARIETTA MATLS COM 573284106 1,628 -42 -2.51 627 -14.81 0.0010
2022-02-03 2021-12-31 13F MARTIN MARIETTA MATLS COM 573284106 1,670 -62 -3.58 736 24.32 0.0012
2021-11-15 2021-09-30 13F MARTIN MARIETTA MATLS COM 573284106 1,732 47 2.79 592 0.00 0.0011
2021-08-13 2021-06-30 13F MARTIN MARIETTA MATLS COM 573284106 1,685 -2,571 -60.41 592 -58.57 0.0011
2021-05-14 2021-03-31 13F MARTIN MARIETTA MATLS COM 573284106 4,256 2,661 166.83 1,429 215.45 0.0030
2021-02-12 2020-12-31 13F MARTIN MARIETTA MATLS COM 573284106 1,595 11 0.69 453 21.45 0.0010
2020-11-13 2020-09-30 13F MARTIN MARIETTA MATLS COM 573284106 1,584 -553 -25.88 373 -15.42 0.0010
2020-08-14 2020-06-30 13F MARTIN MARIETTA MATLS COM 573284106 2,137 779 57.36 441 71.60 0.0014
2020-05-08 2020-03-31 13F MARTIN MARIETTA MATLS COM 573284106 1,358 31 2.34 257 -30.73 0.0010
2020-02-13 2019-12-31 13F MARTIN MARIETTA MATLS COM 573284106 1,327 269 25.43 371 27.93 0.0013
2019-11-12 2019-09-30 13F MARTIN MARIETTA MATLS COM 573284106 1,058 -194 -15.50 290 0.69 0.0011
2019-08-12 2019-06-30 13F MARTIN MARIETTA MATLS COM 573284106 1,252 115 10.11 288 25.76 0.0012
2019-05-10 2019-03-31 13F MARTIN MARIETTA MATLS COM 573284106 1,137 -15 -1.30 229 15.66 0.0010
2019-02-12 2018-12-31 13F MARTIN MARIETTA MATLS COM 573284106 1,152 -37 -3.11 198 -8.33 0.0010
2018-11-01 2018-09-30 13F MARTIN MARIETTA MATLS COM 573284106 1,189 223 23.08 216 0.47 0.0011
2018-08-10 2018-06-30 13F MARTIN MARIETTA MATLS COM 573284106 966 97 11.16 215 19.44 0.0012
2018-05-14 2018-03-31 13F MARTIN MARIETTA MATLS COM 573284106 869 9 1.05 180 -5.26 0.0011
2018-01-31 2017-12-31 13F MARTIN MARIETTA MATLS COM 573284106 860 -60 -6.52 190 0.00 0.0012
2017-11-07 2017-09-30 13F MARTIN MARIETTA MATLS COM 573284106 920 -257 -21.84 190 -27.48 0.0014
2017-08-10 2017-06-30 13F MARTIN MARIETTA MATLS COM 573284106 1,177 90 8.28 262 10.55 0.0021
2017-05-09 2017-03-31 13F MARTIN MARIETTA MATLS COM 573284106 1,087 143 15.15 237 13.40 0.0022
2017-02-15 2016-12-31 13F MARTIN MARIETTA MATLS COM 573284106 944 97 11.45 209 38.41 0.0023
2016-11-14 2016-09-30 13F MARTIN MARIETTA MATLS COM 573284106 847 317 59.81 151 49.50 0.0023
2016-08-29 2016-06-30 13F MARTIN MARIETTA MATLS COM 573284106 530 5 0.95 101 20.24 0.0014
2016-05-16 2016-03-31 13F MARTIN MARIETTA MATLS COM 573284106 525 -67 -11.32 84 3.70 0.0014
2016-02-16 2015-12-31 13F MARTIN MARIETTA MATLS COM 573284106 592 89 17.69 81 6.58 0.0016
2015-11-16 2015-09-30 13F MARTIN MARIETTA MATLS COM 573284106 503 322 177.90 76 204.00 0.0018
2015-09-30 2015-06-30 13F/A-1 MARTIN MARIETTA MATLS COM 573284106 181 50 38.17 25 38.89 0.0006
2015-08-14 2015-06-30 13F MARTIN MARIETTA MATLS COM 573284106 131 18
2015-05-15 2015-03-31 13F MARTIN MARIETTA MATLS COM 573284106 131 100 322.58 18 500.00 0.0005
2015-02-13 2014-12-31 13F MARTIN MARIETTA MATLS COM 573284106 31 -14 -31.11 3 -50.00 0.0001
2014-11-14 2014-09-30 13F MARTIN MARIETTA MATLS COM 573284106 45 0 0.00 6 0.00 0.0002
2014-08-05 2014-06-30 13F MARTIN MARIETTA MATLS COM 573284106 45 0 0.00 6 0.00 0.0002
2014-05-15 2014-03-31 13F MARTIN MARIETTA MATLS COM 573284106 45 -15 -25.00 6 0.00 0.0003
2014-02-14 2013-12-31 13F MARTIN MARIETTA MATLS COM 573284106 60 46 328.57 6 500.00 0.0003
2013-11-14 2013-09-30 13F MARTIN MARIETTA MATLS COM 573284106 14 0 0.00 1 0.00 0.0001
2013-08-21 2013-06-30 13F/A-1 MARTIN MARIETTA MATLS COM 573284106 14 14 1 0.0001
2013-08-14 2013-06-30 13F MARTIN MARIETTA MATLS COM 573284106 22,580 2,222 0.0244
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.