Martin Marietta Materials, Inc.
MX ˙ BMV ˙ US5732841060
SecurityMX:MLM / Martin Marietta Materials, Inc.
InstitutionStonebridge Capital Management Inc
Latest Disclosed Ownership975 shares
Latest Disclosed Value $ 573,963
Stonebridge Capital Management Inc ownership in MLM / Martin Marietta Materials, Inc.

On April 13, 2026 - Stonebridge Capital Management Inc filed a 13F-HR form disclosing ownership of 975 shares of Martin Marietta Materials, Inc. (MX:MLM) valued at $573,963 USD as of March 31, 2026. The entity filed a previous 13F-HR on July 1, 2025 disclosing 975 shares of Martin Marietta Materials, Inc..

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)
2026-04-13 2026-03-31 13F MARTIN MARIETTA MATLS COM 573284106 975 0 0.00 574 0.2610
2025-07-01 2025-06-30 13F MARTIN MARIETTA MATLS INC COM COM 573284106 975 0 0.00 1 0.2092
2025-05-12 2025-03-31 13F MARTIN MARIETTA MATLS INC COM COM 573284106 975 0 0.00 0 0.2014
2025-01-14 2024-12-31 13F MARTIN MARIETTA MATLS INC COM COM 573284106 975 -40 -3.94 1 0.2064
2024-10-07 2024-09-30 13F MARTIN MARIETTA MATLS INC COM COM 573284106 1,015 -50 -4.69 1 0.2167
2024-07-09 2024-06-30 13F MARTIN MARIETTA MATLS INC COM COM 573284106 1,065 0 0.00 1 0.2462
2024-04-15 2024-03-31 13F MARTIN MARIETTA MATLS INC COM COM 573284106 1,065 0 0.00 1 0.2924
2024-03-05 2023-12-31 13F MARTIN MARIETTA MATLS INC COM COM 573284106 1,065 0 0.00 1 0.2590
2023-12-13 2023-09-30 13F MARTIN MARIETTA MATLS INC COM COM 573284106 1,065 -500 -31.95 0 0.2387
2023-07-06 2023-06-30 13F MARTIN MARIETTA MATLS INC COM COM 573284106 1,565 -150 -8.75 1 0.3367
2023-04-04 2023-03-31 13F MARTIN MARIETTA MATLS INC COM COM 573284106 1,715 0 0.00 1 -100.00 0.2926
2023-01-06 2022-12-31 13F MARTIN MARIETTA MATLS INC COM COM 573284106 1,715 0 0.00 1 -100.00 0.2772
2022-10-06 2022-09-30 13F MARTIN MARIETTA MATLS INC COM COM 573284106 1,715 0 0.00 552 7.60 0.2853
2022-07-01 2022-06-30 13F MARTIN MARIETTA MATLS INC COM COM 573284106 1,715 0 0.00 513 -22.27 0.2340
2022-04-04 2022-03-31 13F MARTIN MARIETTA MATLS INC COM COM 573284106 1,715 0 0.00 660 -12.58 0.2381
2022-01-05 2021-12-31 13F MARTIN MARIETTA MATLS INC COM COM 573284106 1,715 0 0.00 755 28.84 0.2627
2021-10-07 2021-09-30 13F MARTIN MARIETTA MATLS INC COM COM 573284106 1,715 0 0.00 586 -2.82 0.2150
2021-07-06 2021-06-30 13F MARTIN MARIETTA MATLS INC COM COM 573284106 1,715 0 0.00 603 4.69 0.2192
2021-04-05 2021-03-31 13F MARTIN MARIETTA MATLS INC COM COM 573284106 1,715 0 0.00 576 18.28 0.2198
2021-01-06 2020-12-31 13F MARTIN MARIETTA MATLS INC COM COM 573284106 1,715 -30 -1.72 487 18.49 0.2014
2020-12-11 2020-09-30 13F MARTIN MARIETTA MAT COM 573284106 1,745 -15 -0.85 411 11.68 0.1897
2020-07-07 2020-06-30 13F MARTIN MARIETTA MATLS INC COM COM 573284106 1,760 -250 -12.44 368 -3.16 0.1893
2020-05-20 2020-03-31 13F MARTIN MARIETTA MATLS INC COM COM 573284106 2,010 -35 -1.71 380 -33.57 0.2129
2020-01-02 2019-12-31 13F MARTIN MARIETTA MATLS INC COM COM 573284106 2,045 -75 -3.54 572 -1.55 0.2503
2019-10-02 2019-09-30 13F MARTIN MARIETTA MATLS INC COM COM 573284106 2,120 -745 -26.00 581 -11.84 0.2693
2019-07-12 2019-06-30 13F MARTIN MARIETTA MATLS COM 573284106 2,865 -1,410 -32.98 659 -23.37 0.2597
2019-05-02 2019-03-31 13F MARTIN MARIETTA MATLS COM 573284106 4,275 -1,840 -30.09 860 -18.17 0.3139
2019-01-25 2018-12-31 13F/A-1 MARTIN MARIETTA MATLS COM 573284106 6,115 6,115 1,051 0.4199
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.