Martin Marietta Materials, Inc.
MX ˙ BMV ˙ US5732841060
SecurityMX:MLM / Martin Marietta Materials, Inc.
InstitutionCongress Asset Management Co /ma
Latest Disclosed Ownership237,971 shares
Latest Disclosed Value $ 140,088,832
Congress Asset Management Co /ma reports 0.69% decrease in ownership of MLM / Martin Marietta Materials, Inc.

On April 14, 2026 - Congress Asset Management Co /ma filed a 13F-HR form disclosing ownership of 237,971 shares of Martin Marietta Materials, Inc. (MX:MLM) valued at $140,088,832 USD as of March 31, 2026. The entity filed a previous 13F-HR on January 9, 2026 disclosing 239,634 shares of Martin Marietta Materials, Inc.. This represents a change in shares of -0.69% 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)
2026-04-14 2026-03-31 13F Martin Marietta Materials COM 573284106 237,971 -1,663 -0.69 140,089 -6.11 1.0040
2026-01-09 2025-12-31 13F Martin Marietta Materials COM 573284106 239,634 -4,866 -1.99 149,210 -3.18 1.0502
2025-10-10 2025-09-30 13F Martin Marietta Materials COM 573284106 244,500 -1,786 -0.73 154,103 13.98 1.0255
2025-07-16 2025-06-30 13F Martin Marietta Materials COM 573284106 246,286 -7,663 -3.02 135,201 11.35 0.9274
2025-04-11 2025-03-31 13F Martin Marietta Matls Inc Com COM 573284106 253,949 -167 -0.07 121,421 -7.49 0.9082
2025-01-30 2024-12-31 13F Martin Marietta Matls Inc Com COM 573284106 254,116 938 0.37 131,251 -3.68 0.8871
2024-10-28 2024-09-30 13F Martin Marietta Matls Inc Com COM 573284106 253,178 1,242 0.49 136,273 -0.17 0.9291
2024-08-02 2024-06-30 13F Martin Marietta Matls Inc Com COM 573284106 251,936 2,429 0.97 136,499 -10.89 0.9782
2024-04-11 2024-03-31 13F Martin Marietta Matls Inc Com COM 573284106 249,507 524 0.21 153,182 23.32 1.0924
2024-03-04 2023-12-31 13F Martin Marietta Matls Inc Com COM 573284106 248,983 3,027 1.23 124,220 23.04 0.9778
2023-11-01 2023-09-30 13F Martin Marietta Materials COM 573284106 245,956 3,362 1.39 100,960 -9.86 0.8929
2023-07-27 2023-06-30 13F Martin Marietta Materials COM 573284106 242,594 174,835 258.02 112,003 365.55 0.9729
2023-04-21 2023-03-31 13F Martin Marietta Materials COM 573284106 67,759 595 0.89 24,058 5.99 0.2242
2023-01-18 2022-12-31 13F Martin Marietta Materials COM 573284106 67,164 -5,812 -7.96 22,699 -3.43 0.2276
2022-11-08 2022-09-30 13F Martin Marietta Materials COM 573284106 72,976 1,111 1.55 23,505 9.30 0.2520
2022-08-02 2022-06-30 13F Martin Marietta Materials COM 573284106 71,865 -378 -0.52 21,505 -22.66 0.2058
2022-04-20 2022-03-31 13F Martin Marietta Materials COM 573284106 72,243 -1,995 -2.69 27,806 -14.97 0.2365
2022-01-28 2021-12-31 13F Martin Marietta Materials COM 573284106 74,238 -9,898 -11.76 32,703 13.76 0.2490
2021-11-08 2021-09-30 13F Martin Marietta Materials COM 573284106 84,136 10,396 14.10 28,748 10.82 0.2244
2021-08-05 2021-06-30 13F Martin Marietta Materials COM 573284106 73,740 898 1.23 25,942 6.05 0.2170
2021-05-05 2021-03-31 13F Martin Marietta Materials COM 573284106 72,842 -3,063 -4.04 24,462 13.49 0.2209
2021-01-26 2020-12-31 13F Martin Marietta Materials COM 573284106 75,905 987 1.32 21,555 22.24 0.2030
2020-11-03 2020-09-30 13F Martin Marietta Materials COM 573284106 74,918 39,294 110.30 17,633 139.61 0.1909
2020-07-23 2020-06-30 13F Martin Marietta Materials COM 573284106 35,624 35,624 7,359 0.0875
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.