MPLX LP - Limited Partnership
US ˙ NYSE ˙ US55336V1008

SecurityMPLX / MPLX LP - Limited Partnership
InstitutionAdvisor Group Holdings, Inc.
Latest Disclosed Ownership121,803 shares
Latest Disclosed Value $ 6,951,967
Advisor Group Holdings, Inc. ownership in MPLX / MPLX LP - Limited Partnership

On May 15, 2026 - Advisor Group Holdings, Inc. filed a 13F-HR form disclosing ownership of 121,803 shares of MPLX LP - Limited Partnership (US:MPLX) valued at $6,951,297 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 17, 2026 disclosing 150,746 shares of MPLX LP - Limited Partnership. This represents a change in shares of -19.20% during the quarter. The current value of the position is $6,730,834 USD.

Advisor Group Holdings, Inc. has a history of taking positions in derivatives of the underlying security (MPLX) in the form of stock options. The firm currently holds call options representing 0 of underlying shares valued at $0 USD and put options representing 0 of underlying shares valued at $0 USD .

Note: prior versions of this page mistakenly stated that the share values represented the number of options, not the number of underlying shares. For more information on the data backing these reports, please see the SEC document Frequently Asked Questions About Form 13F.

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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Institutional Put/Call Ratios
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In addition to reporting standard equity and debt issues, institutions with more than 100MM assets under management must also disclose their put and call option holdings. Since put options generally indicate negative sentiment, and call options indicate positive sentiment, we can get a sense of the overall institutional sentiment by plotting the ratio of puts to calls. The chart to the right plots the historical put/call ratio for this instrument.

Using Put/Call Ratio as an indicator of investor sentiment overcomes one of the key deficiencies of using total institutional ownership, which is that a significant amount of assets under management are invested passively to track indices. Passively-managed funds do not typically buy options, so the put/call ratio indicator more closely tracks the sentiment of actively-managed funds.

MPLX / MPLX LP - Limited Partnership Historical Put/Call Ratio
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)
2026-05-15 2026-03-31 13F MPLX COM UNIT REP LTD 55336V100 121,803 -28,943 -19.20 6,952 -13.60 0.0059
2026-02-17 2025-12-31 13F MPLX COM UNIT REP LTD 55336V100 150,746 18,579 14.06 8,046 20.52 0.0118
2025-11-14 2025-09-30 13F MPLX COM UNIT REP LTD 55336V100 132,167 -8,158 -5.81 6,676 -7.65 0.0093
2025-09-04 2025-06-30 13F/A-1 PLX COM UNIT REP LTD 55336V100 140,325 3,954 2.90 7,229 -0.97 0.0129
2025-08-13 2025-06-30 13F PLX COM UNIT REP LTD 55336V100 123,785 -12,586 6,057 0.0070
2025-05-12 2025-03-31 13F MPLX COM UNIT REP LTD 55336V100 136,371 44,720 48.79 7,299 66.42 0.0163
2025-06-06 2024-12-31 13F/A-1 MPLX COM UNIT REP LTD 55336V100 91,651 -13,948 -13.21 4,387 -6.58 0.0098
2025-02-07 2024-12-31 13F MPLX COM UNIT REP LTD 55336V100 80,753 -24,846 3,604 0.0092
2024-11-13 2024-09-30 13F MPLX COM UNIT REP LTD 55336V100 105,599 -12,198 -10.36 4,695 -6.42 0.0106
2024-08-13 2024-06-30 13F MPLX COM UNIT REP LTD 55336V100 117,797 -16,681 -12.40 5,017 -10.23 0.0119
2024-05-10 2024-03-31 13F MPLX COM UNIT REP LTD 55336V100 134,478 -1,352 -1.00 5,589 12.05 0.0125
2024-02-12 2023-12-31 13F MPLX COM UNIT REP LTD 55336V100 135,830 -61,714 -31.24 4,988 -29.02 0.0087
2023-11-13 2023-09-30 13F MPLX COM UNIT REP LTD 55336V100 197,544 39,106 24.68 7,027 30.61 0.0104
2023-08-21 2023-06-30 13F/A-1 MPLX COM UNIT REP LTD 55336V100 158,438 32,497 25.80 5,381 23.99 0.0097
2023-08-10 2023-06-30 13F MPLX COM UNIT REP LTD 55336V100 158,438 32,497 5,381 0.0015
2023-05-12 2023-03-31 13F MPLX COM UNIT REP LTD 55336V100 125,941 -13,994 -10.00 4,339 -5.61 0.0082
2023-02-10 2022-12-31 13F MPLX COM UNIT REP LTD 55336V100 139,935 32,742 30.54 4,597 42.85 0.0093
2022-11-14 2022-09-30 13F MPLX COM UNIT REP LTD 55336V100 107,193 29,568 38.09 3,218 42.08 0.0074
2022-08-10 2022-06-30 13F MPLX COM UNIT REP LTD 55336V100 77,625 -5,169 -6.24 2,265 -13.91 0.0050
2022-05-04 2022-03-31 13F MPLX COM UNIT REP LTD 55336V100 82,794 -9,015 -9.82 2,631 -3.17 0.0051
2022-02-03 2021-12-31 13F MPLX COM UNIT REP LTD 55336V100 91,809 9,794 11.94 2,717 16.16 0.0051
2021-11-05 2021-09-30 13F MPLX COM UNIT REP LTD 55336V100 82,015 9,766 13.52 2,339 9.30 0.0049
2021-08-02 2021-06-30 13F MPLX COM UNIT REP LTD 55336V100 72,249 -41,808 -36.66 2,140 -26.84 0.0046
2021-05-13 2021-03-31 13F MPLX COM UNIT REP LTD 55336V100 114,057 -80,007 -41.23 2,925 -30.39 0.0070
2021-02-10 2020-12-31 13F MPLX COM UNIT REP LTD 55336V100 194,064 -74,265 -27.68 4,202 -0.52 0.0112
2020-11-12 2020-09-30 13F MPLX COM UNIT REP LTD 55336V100 268,329 32,815 13.93 4,224 3.78 0.0126
2020-08-14 2020-06-30 13F MPLX COM UNIT REP LTD 55336V100 235,514 -26,680 -10.18 4,070 38.91 0.0137
2020-05-18 2020-03-31 13F MPLX COM UNIT REP LTD 55336V100 262,194 262,194 2,930 0.0120
Disclosed Call Options
File
Date
Effective
Date
Form Security Class ID Opt Avg Share
Price
Shares ΔShares
(%)
Value
(x1000)
ΔValue
(%)
Prior Allocation
(%)
Allocation
(%)
ΔAllocation
(%)
Cost Basis
(x1000)
Profit
(x1000)
Return
(%)
2022-02-03 2021-12-31 13F MPLX LP CALL COM UNIT REP LTD Call 0 -100.00 0 -100.00 n/a n/a n/a
2021-11-05 2021-09-30 13F MPLX LP CALL COM UNIT REP LTD Call 10 0.00 8 -11.11 n/a n/a n/a
2021-08-02 2021-06-30 13F MPLX LP CALL COM UNIT REP LTD Call 10 0.00 9 80.00 n/a n/a n/a
2021-05-13 2021-03-31 13F MPLX LP CALL COM UNIT REP LTD Call 10 -98.23 5 -94.95 n/a n/a n/a
2021-02-10 2020-12-31 13F MPLX LP CALL COM UNIT REP LTD Call 565 276.67 99 1,000.00 n/a n/a n/a
2020-11-12 2020-09-30 13F MPLX LP CALL COM UNIT REP LTD Call 150 -52.38 9 -79.07 n/a n/a n/a
2020-08-14 2020-06-30 13F MPLX LP CALL COM UNIT REP LTD Call 315 530.00 43 514.29 n/a n/a n/a
2020-05-18 2020-03-31 13F MPLX LP CALL COM UNIT REP LTD Call 50 7 n/a n/a n/a
Disclosed Put Options
File
Date
Effective
Date
Form Security Class ID Opt Avg Share Price Shares ΔShares
(%)
Value
(x1000)
ΔValue
(%)
Prior Allocation
(%)
Allocation
(%)
ΔAllocation
(%)
Cost Basis
(x1000)
Profit
(x1000)
Return
(%)
2022-02-03 2021-12-31 13F MPLX LP PUT COM UNIT REP LTD Put 0 -100.00 0 n/a n/a n/a
2021-11-05 2021-09-30 13F MPLX LP PUT COM UNIT REP LTD Put 5 0.00 0 n/a n/a n/a
2021-08-02 2021-06-30 13F MPLX LP PUT COM UNIT REP LTD Put 5 -96.27 0 -100.00 n/a n/a n/a
2021-05-13 2021-03-31 13F MPLX LP PUT COM UNIT REP LTD Put 134 -64.74 18 -65.38 n/a n/a n/a
2021-02-10 2020-12-31 13F MPLX LP PUT COM UNIT REP LTD Put 380 52 n/a n/a n/a
2020-11-12 2020-09-30 13F MPLX LP PUT COM UNIT REP LTD Put 0 -100.00 0 -100.00 n/a n/a n/a
2020-08-14 2020-06-30 13F MPLX LP PUT COM UNIT REP LTD Put 48 -85.00 8 -81.40 n/a n/a n/a
2020-05-18 2020-03-31 13F MPLX LP PUT COM UNIT REP LTD Put 320 43 n/a n/a n/a
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.