Marathon Petroleum Corporation
MX ˙ BMV ˙ US56585A1025
SecurityMX:MPC / Marathon Petroleum Corporation
InstitutionIpswich Investment Management Co., Inc.
Latest Disclosed Ownership1,763 shares
Latest Disclosed Value $ 430,489
Ipswich Investment Management Co., Inc. reports 24.77% increase in ownership of MPC / Marathon Petroleum Corporation

On April 10, 2026 - Ipswich Investment Management Co., Inc. filed a 13F-HR form disclosing ownership of 1,763 shares of Marathon Petroleum Corporation (MX:MPC) valued at $430,489 USD as of March 31, 2026. The entity filed a previous 13F-HR on January 16, 2026 disclosing 1,413 shares of Marathon Petroleum Corporation. This represents a change in shares of 24.77% 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)
2026-04-10 2026-03-31 13F MARATHON PETE COM 56585A102 1,763 350 24.77 430 87.77 0.1011
2026-01-16 2025-12-31 13F MARATHON PETE COM 56585A102 1,413 -187 -11.69 230 -25.65 0.0532
2025-10-08 2025-09-30 13F MARATHON PETE COM 56585A102 1,600 -25 -1.54 308 14.50 0.0720
2025-07-16 2025-06-30 13F MARATHON PETE COM 56585A102 1,625 0 0.00 270 13.98 0.0651
2025-04-16 2025-03-31 13F MARATHON PETE COM 56585A102 1,625 0 0.00 237 4.42 0.0588
2025-02-03 2024-12-31 13F MARATHON PETE COM 56585A102 1,625 -150 -8.45 227 -21.80 0.0545
2024-11-06 2024-09-30 13F MARATHON PETE COM 56585A102 1,775 0 0.00 289 -5.86 0.0670
2024-07-16 2024-06-30 13F MARATHON PETE COM 56585A102 1,775 -112 -5.94 308 -19.21 0.0721
2024-04-19 2024-03-31 13F MARATHON PETE COM 56585A102 1,887 -13 -0.68 380 35.23 0.0891
2024-01-31 2023-12-31 13F MARATHON PETE COM 56585A102 1,900 0 0.00 282 -2.09 0.0713
2023-11-08 2023-09-30 13F MARATHON PETE COM 56585A102 1,900 0 0.00 288 29.86 0.0785
2023-07-27 2023-06-30 13F MARATHON PETE COM 56585A102 1,900 -750 -28.30 222 -38.10 0.0583
2023-04-24 2023-03-31 13F MARATHON PETE COM 56585A102 2,650 0 0.00 357 15.91 0.0977
2023-02-01 2022-12-31 13F MARATHON PETE COM 56585A102 2,650 -210 -7.34 308 8.45 0.0883
2022-10-11 2022-09-30 13F MARATHON PETE COM 56585A102 2,860 -2 -0.07 284 20.85 0.0904
2022-07-26 2022-06-30 13F MARATHON PETE COM 56585A102 2,862 0 0.00 235 -4.08 0.0676
2022-04-25 2022-03-31 13F/A-1 MARATHON PETE COM 56585A102 2,862 2,862 245 0.0608
2022-04-12 2022-03-31 13F MARATHON PETE COM 56585A102 2,862 2,862 245 0.0608
2020-04-09 2020-03-31 13F MARATHON PETE COM 56585A102 0 -3,414 -100.00 0 -100.00
2020-01-08 2019-12-31 13F MARATHON PETE COM 56585A102 3,414 -16 -0.47 206 -0.96 0.0606
2019-10-08 2019-09-30 13F MARATHON PETE COM 56585A102 3,430 3,430 208 0.0663
2019-07-11 2019-06-30 13F MARATHON PETE COM 56585A102 0 -3,430 -100.00 0 -100.00
2019-04-12 2019-03-31 13F MARATHON PETE COM 56585A102 3,430 -30 -0.87 205 0.49 0.0670
2019-01-15 2018-12-31 13F MARATHON PETE COM 56585A102 3,460 -47 -1.34 204 -27.14 0.0748
2018-10-09 2018-09-30 13F MARATHON PETE COM 56585A102 3,507 3,507 280 0.0947
2018-07-18 2018-06-30 13F MARATHON PETE COM 56585A102 0 -3,587 -100.00 0 -100.00
2018-04-12 2018-03-31 13F MARATHON PETE COM 56585A102 3,587 -14 -0.39 262 10.08 0.1105
2018-01-16 2017-12-31 13F MARATHON PETE COM 56585A102 3,601 -59 -1.61 238 16.10 0.1008
2017-10-11 2017-09-30 13F MARATHON PETE COM 56585A102 3,660 3,660 205 0.0920
2016-08-02 2016-06-30 13F MARATHON PETE COM 56585A102 0 -3,660 -100.00 0 -100.00
2016-05-11 2016-03-31 13F MARATHON PETE COM 56585A102 3,660 -2,328 -38.88 128 -58.71 0.0609
2016-01-13 2015-12-31 13F MARATHON PETE COM 56585A102 5,988 0 0.00 310 11.91 0.1398
2015-10-26 2015-09-30 13F MARATHON PETE COM 56585A102 5,988 -100 -1.64 277 -12.89 0.1319
2015-08-20 2015-06-30 13F MARATHON PETE COM 56585A102 6,088 2,944 93.64 318 -1.24 0.1433
2015-04-08 2015-03-31 13F MARATHON PETE COM 56585A102 3,144 0 0.00 322 13.38 0.1411
2015-01-20 2014-12-31 13F MARATHON PETE COM 56585A102 3,144 -2,900 -47.98 284 -44.53 0.1210
2014-10-08 2014-09-30 13F MARATHON PETE COM 56585A102 6,044 -236 -3.76 512 4.49 0.2179
2014-07-15 2014-06-30 13F MARATHON PETE COM 56585A102 6,280 0 0.00 490 -10.42 0.1898
2014-04-15 2014-03-31 13F MARATHON PETE COM 56585A102 6,280 -1,995 -24.11 547 -27.93 0.2354
2014-01-16 2013-12-31 13F MARATHON PETE COM 56585A102 8,275 0 0.00 759 42.67 0.3170
2013-10-25 2013-09-30 13F/A-1 MARATHON PETE COM 56585A102 8,275 0 0.00 532 -9.52 0.2393
2013-10-21 2013-09-30 13F MARATHON PETE COM 56585A102 8,275 532
2013-07-17 2013-06-30 13F MARATHON PETE COM 56585A102 8,275 8,275 588 0.2536
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.