Martin Marietta Materials, Inc.
MX ˙ BMV ˙ US5732841060
SecurityMX:MLM / Martin Marietta Materials, Inc.
InstitutionBoston Private Wealth Llc
Latest Disclosed Ownership1,384 shares
Latest Disclosed Value $ 814,573
Boston Private Wealth Llc reports 3.96% decrease in ownership of MLM / Martin Marietta Materials, Inc.

On April 17, 2026 - Boston Private Wealth Llc filed a 13F-HR form disclosing ownership of 1,384 shares of Martin Marietta Materials, Inc. (MX:MLM) valued at $814,573 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 4, 2026 disclosing 1,441 shares of Martin Marietta Materials, Inc.. This represents a change in shares of -3.96% 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)
2026-04-17 2026-03-31 13F MARTIN MARIETTA MATERIALS COM 573284106 1,384 -57 -3.96 815 -9.25 0.0537
2026-02-04 2025-12-31 13F MARTIN MARIETTA MATERIALS COM 573284106 1,441 -6 -0.41 897 -1.64 0.0529
2025-11-06 2025-09-30 13F MARTIN MARIETTA MATERIALS COM 573284106 1,447 -185 -11.34 912 1.79 0.0491
2025-08-14 2025-06-30 13F MARTIN MARIETTA MATERIALS COM 573284106 1,632 1,632 896 0.0480
2025-05-14 2025-03-31 13F MARTIN MARIETTA MATERIALS COM 573284106 0 -2,446 -100.00 0 -100.00
2025-02-05 2024-12-31 13F MARTIN MARIETTA MATERIALS COM 573284106 2,446 2,446 1,263 0.0236
2024-10-18 2024-09-30 13F MARTIN MARIETTA MATERIALS COM 573284106 0 -3,496 -100.00 0 -100.00
2024-08-06 2024-06-30 13F MARTIN MARIETTA MATERIALS COM 573284106 3,496 -8,064 -69.76 1,894 -73.31 0.0469
2024-05-15 2024-03-31 13F MARTIN MARIETTA MATERIALS COM 573284106 11,560 -1,473 -11.30 7,097 9.15 0.1582
2024-01-30 2023-12-31 13F MARTIN MARIETTA MATERIALS COM 573284106 13,033 -4,649 -26.29 6,502 -10.42 0.1582
2023-10-23 2023-09-30 13F MARTIN MARIETTA MATERIALS COM 573284106 17,682 -1,101 -5.86 7,258 -16.30 0.1594
2023-07-24 2023-06-30 13F MARTIN MARIETTA MATERIALS COM 573284106 18,783 -1,664 -8.14 8,672 19.45 0.1567
2023-05-12 2023-03-31 13F MARTIN MARIETTA MATERIALS COM 573284106 20,447 -2,407 -10.53 7,260 -6.02 0.1015
2023-02-10 2022-12-31 13F Martin Marietta Materials COM 573284106 22,854 -229 -0.99 7,724 3.90 0.1043
2022-11-09 2022-09-30 13F Martin Marietta Materials COM 573284106 23,083 -303 -1.30 7,434 6.23 0.1086
2022-08-16 2022-06-30 13F Martin Marietta Materials COM 573284106 23,386 -222 -0.94 6,998 -22.98 0.1076
2022-05-13 2022-03-31 13F Martin Marietta Materials COM 573284106 23,608 -4,787 -16.86 9,086 -27.36 0.1217
2022-02-15 2021-12-31 13F Martin Marietta Materials COM 573284106 28,395 396 1.41 12,509 30.75 0.2051
2021-11-09 2021-09-30 13F Martin Marietta Materials COM 573284106 27,999 169 0.61 9,567 -2.29 0.1229
2021-08-13 2021-06-30 13F Martin Marietta Materials COM 573284106 27,830 1,537 5.85 9,791 10.88 0.1241
2021-05-11 2021-03-31 13F Martin Marietta Materials COM 573284106 26,293 -1,213 -4.41 8,830 13.05 0.1230
2021-02-10 2020-12-31 13F Martin Marietta Materials COM 573284106 27,506 1,069 4.04 7,811 25.52 0.1146
2020-11-10 2020-09-30 13F Martin Marietta Materials COM 573284106 26,437 1,301 5.18 6,223 19.86 0.1026
2020-08-05 2020-06-30 13F Martin Marietta Materials COM 573284106 25,136 -598 -2.32 5,192 6.61 0.0965
2020-05-11 2020-03-31 13F Martin Marietta Materials COM 573284106 25,734 -1,357 -5.01 4,870 -35.72 0.1182
2020-02-13 2019-12-31 13F Martin Marietta Materials COM 573284106 27,091 -30 -0.11 7,576 1.91 0.1379
2019-11-01 2019-09-30 13F Martin Marietta Materials COM 573284106 27,121 -1,987 -6.83 7,434 10.99 0.1480
2019-07-10 2019-06-30 13F Martin Marietta Materials COM 573284106 29,108 -1,878 -6.06 6,698 7.44 0.2250
2019-05-14 2019-03-31 13F Martin Marietta Materials COM 573284106 30,986 -1,687 -5.16 6,234 11.02 0.2462
2019-02-14 2018-12-31 13F Martin Marietta Materials COM 573284106 32,673 -18,561 -36.23 5,615 -39.77 0.2396
2018-11-13 2018-09-30 13F Martin Marietta Materials COM 573284106 51,234 -653 -1.26 9,322 -19.55 0.3297
2018-08-14 2018-06-30 13F Martin Marietta Materials COM 573284106 51,887 -4,571 -8.10 11,588 -0.99 0.4444
2018-05-11 2018-03-31 13F Martin Marietta Materials COM 573284106 56,458 2,124 3.91 11,704 -2.55 0.4489
2018-02-13 2017-12-31 13F Martin Marietta Materials COM 573284106 54,334 54,334 12,010 0.4518
2017-05-11 2017-03-31 13F Martin Marietta Materials COM 573284106 0 -5,524 -100.00 0 -100.00
2017-02-15 2016-12-31 13F Martin Marietta Materials COM 573284106 5,524 -250 -4.33 1,224 18.38 0.0506
2016-11-15 2016-09-30 13F/A-1 Martin Marietta Materials COM 573284106 5,774 -85 -1.45 1,034 -8.09 0.0421
2016-11-14 2016-09-30 13F Martin Marietta Materials COM 573284106 5,859 0 1,125 0.0459
2016-08-01 2016-06-30 13F Martin Marietta Materials COM 573284106 5,859 -200 -3.30 1,125 16.46 0.0459
2016-05-13 2016-03-31 13F Martin Marietta Materials COM 573284106 6,059 -843 -12.21 966 2.44 0.0393
2016-02-12 2015-12-31 13F Martin Marietta Materials COM 573284106 6,902 -731 -9.58 943 -18.71 0.0372
2015-11-12 2015-09-30 13F Martin Marietta Materials COM 573284106 7,633 -2,252 -22.78 1,160 -17.08 0.0450
2015-08-13 2015-06-30 13F Martin Marietta Materials COM 573284106 9,885 -852 -7.94 1,399 -6.80 0.0463
2015-05-12 2015-03-31 13F Martin Marietta Materials COM 573284106 10,737 30 0.28 1,501 27.10 0.0485
2015-02-10 2014-12-31 13F Martin Marietta Materials COM 573284106 10,707 10,707 1,181 0.0382
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.