Martin Marietta Materials, Inc.
US ˙ NYSE ˙ US5732841060

SecurityMLM / Martin Marietta Materials, Inc.
InstitutionGilbert & Cook, Inc.
Latest Disclosed Ownership2,129 shares
Latest Disclosed Value $ 1,253,213
Gilbert & Cook, Inc. reports 0.28% decrease in ownership of MLM / Martin Marietta Materials, Inc.

On May 5, 2026 - Gilbert & Cook, Inc. filed a 13F-HR form disclosing ownership of 2,129 shares of Martin Marietta Materials, Inc. (US:MLM) valued at $1,253,300 USD as of March 31, 2026. The entity filed a previous 13F-HR on January 7, 2026 disclosing 2,135 shares of Martin Marietta Materials, Inc.. This represents a change in shares of -0.28% during the quarter. The current value of the position is $1,241,526 USD.

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)
2026-05-05 2026-03-31 13F MARTIN MARIETTA MATLS COM 573284106 2,129 -6 -0.28 1,253 -5.72 0.1619
2026-01-07 2025-12-31 13F MARTIN MARIETTA MATLS COM 573284106 2,135 48 2.30 1,329 1.06 0.1671
2025-11-12 2025-09-30 13F MARTIN MARIETTA MATLS COM 573284106 2,087 107 5.40 1,315 21.09 0.1690
2025-08-05 2025-06-30 13F MARTIN MARIETTA MATLS COM 573284106 1,980 39 2.01 1,087 17.15 0.1469
2025-05-06 2025-03-31 13F MARTIN MARIETTA MATLS COM 573284106 1,941 11 0.57 928 -6.93 0.1346
2025-01-23 2024-12-31 13F MARTIN MARIETTA MATLS COM 573284106 1,930 192 11.05 997 6.52 0.1405
2024-11-07 2024-09-30 13F MARTIN MARIETTA MATLS COM 573284106 1,738 436 33.49 935 32.62 0.1286
2024-08-01 2024-06-30 13F MARTIN MARIETTA MATLS COM 573284106 1,302 -87 -6.26 705 -17.25 0.1031
2024-05-02 2024-03-31 13F MARTIN MARIETTA MATLS COM 573284106 1,389 -47 -3.27 853 18.99 0.1162
2024-02-13 2023-12-31 13F/A-1 MARTIN MARIETTA MATLS COM 573284106 1,436 43 3.09 716 25.39 0.1014
2024-02-05 2023-12-31 13F MARTIN MARIETTA MATLS COM 573284106 1,436 43 716 0.1014
2023-11-02 2023-09-30 13F MARTIN MARIETTA MATLS COM 573284106 1,393 222 18.96 572 5.74 0.0902
2023-08-14 2023-06-30 13F MARTIN MARIETTA MATLS COM 573284106 1,171 30 2.63 541 33.33 0.0867
2023-05-05 2023-03-31 13F MARTIN MARIETTA MATLS COM 573284106 1,141 30 2.70 405 8.00 0.0699
2023-02-09 2022-12-31 13F MARTIN MARIETTA MATLS COM 573284106 1,111 21 1.93 375 6.53 0.0683
2022-11-03 2022-09-30 13F MARTIN MARIETTA MATLS COM 573284106 1,090 31 2.93 352 11.04 0.0783
2022-08-05 2022-06-30 13F MARTIN MARIETTA MATERIAL COM 573284106 1,059 27 2.62 317 -20.15 0.0570
2022-05-02 2022-03-31 13F MARTIN MARIETTA MATLS COM 573284106 1,032 308 42.54 397 24.45 0.0643
2022-01-19 2021-12-31 13F MARTIN MARIETTA MATLS COM 573284106 724 6 0.84 319 30.20 0.0513
2022-01-20 2021-09-30 13F/A-1 MARTIN MARIETTA MATLS COM 573284106 718 12 1.70 245 -1.21 0.0438
2021-10-13 2021-09-30 13F MARTIN MARIETTA MATLS COM 573284106 188 -518 245 0.0439
2021-07-13 2021-06-30 13F MARTIN MARIETTA MATLS COM 573284106 706 -18 -2.49 248 2.06 0.0446
2021-04-14 2021-03-31 13F MARTIN MARIETTA MATLS COM 573284106 724 -40 -5.24 243 12.50 0.0478
2021-02-11 2020-12-31 13F MARTIN MARIETTA MATLS COM 573284106 764 764 216 0.0466
2020-05-05 2020-03-31 13F MARTIN MARIETTA MATLS COM 573284106 0 -838 -100.00 0 -100.00
2020-02-03 2019-12-31 13F MARTIN MARIETTA MATLS COM 573284106 838 -156 -15.69 234 -13.97 0.0573
2019-11-05 2019-09-30 13F MARTIN MARIETTA MATLS COM 573284106 994 64 6.88 272 27.10 0.0762
2019-08-05 2019-06-30 13F MARTIN MARIETTA MATLS COM 573284106 930 -120 -11.43 214 1.42 0.0626
2019-05-10 2019-03-31 13F MARTIN MARIETTA MATLS COM 573284106 1,050 1,050 211 0.0641
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.