Third Quarter 2014 Earnings Conference Call and Webcast

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October 30, 2014

Forward‐Looking Statements

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These forward-looking statements relate to, among other things, MPLX's expectations, estimates and projections concerning the business and operations of MPLX. You can identify forward-looking statements by words such as "anticipate," "believe," "estimate," "objective," "expect," "forecast," "project," "potential," "could," "may," "should," "would," "will" or other similar expressions that convey the uncertainty of future events or outcomes. Such forward-looking statements are not guarantees of future performance and are subject to risks, uncertainties and other factors, some of which are beyond the issuer's control and are difficult to predict. Factors that could cause MPLX actual results to differ materially from those in the forward-looking statements include: the adequacy of our capital resources and liquidity, including, but not limited to, availability of sufficient cash flow to pay distributions and execute our business plan; the timing and extent of changes in commodity prices and demand for crude oil, refined products, feedstocks or other hydrocarbon-based products; volatility in and/or degradation of market and industry conditions; completion of pipeline capacity by our competitors; disruptions due to equipment interruption or failure, including electrical shortages and power grid failures; the suspension, reduction or termination of MPC's obligations under our commercial agreements; our ability to successfully implement our growth strategy, whether through organic growth or acquisitions; modifications to earnings and distribution growth objectives; state and federal environmental, economic, health and safety, energy and other policies and regulations; other risk factors inherent to our industry; and the factors set forth under the heading "Risk Factors" in MPLX's Annual Report on Form 10-K for the year ended Dec. 31, 2013, filed with the Securities and Exchange Commission (SEC). Copies of MPLX's Form 10-K are available on the SEC website, MPLX's website at http://ir.mplx.com or by contacting MPLX's Investor Relations office. In addition, unpredictable or unknown factors not discussed here or in MPLX's Form 10-K could also have material adverse effects on forward-looking statements. Other Information Adjusted EBITDA and distributable cash flow are non-GAAP financial measures provided in this presentation. Adjusted EBITDA and distributable cash flow reconciliations to the nearest GAAP financial measure are included in the Appendix to this presentation. Adjusted EBITDA and distributable cash flow are not defined by GAAP and should not be considered in isolation or as an alternative to net income attributable to MPLX or other financial measures prepared in accordance with GAAP.

Highlights Reported adjusted EBITDA of $40.2 million

Generated distributable cash flow of $33.4 million

Increased distribution to $0.3575 per common unit, 4.4 percent over second quarter 2014

Announced plans to substantially accelerate growth of the partnership

MPC has offered to sell its remaining 31 percent interest in MPLX Pipe Line Holdings to MPLX

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111

160

450

-

100

200

300

400

500

Substantial Acceleration of MPLX Growth

Grow MPLX to ~$450 MM of run-rate EBITDA (December 2015 annualized), from current ~$160 MM run-rate (3Q 2014 annualized)

Accelerate MPLX’s annual LP distribution growth rate to average mid-20% over next five years

Evolve MPLX into large-cap, diversified logistics MLP

Evaluate the acquisition of the remaining 31% interest in MPLX Pipe Line Holdings, representing ~$80MM of EBITDA

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Adjusted EBITDA attributable to MPLX

$MM

~3x 3Q 2014 EBITDA

Annualized

Net Income 3Q 2014 vs. 3Q 2013 Variance Analysis

39.2

11.1

7.1

(5.9)

1.9

(7.5) (2.3) (0.5) 43.1

(14.0) 29.1

0

10

20

30

40

50

60

70

3Q 2013(100% Basis)

VolumeDeficiency

Credits

Tariffs Volumes OtherRevenue

and Income

Cost ofRevenues

G&A Other 3Q 2014(100% Basis)

MPCRetainedInterest

3Q 2014Attributable

to MPLX

$MM

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Adjusted EBITDA and Distributable Cash Flow

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($MM) 3Q 2014 3Q 2013

Adjusted EBITDA 57.2 52.8

Less: Adjusted EBITDA attributable to MPC-retained interest 17.0 22.3

Adjusted EBITDA attributable to MPLX LP 40.2 30.5

Plus: Current period deferred revenue for committed volume deficiencies 7.8 5.1

Less: Net interest and other financial costs 1.4 0.5

Maintenance capital expenditures paid 5.8 4.0

Volume deficiency credits 7.4 0.1

Distributable cash flow attributable to MPLX LP 33.4 31.0

Distribution declared

Limited partners – public 7.2 5.9

Limited partner – MPC 19.2 16.1

General partner – MPC 0.5 0.5

Incentive distribution rights – MPC 1.0 -

Total distribution declared 27.9 22.5

Coverage ratio 1.20x 1.38x

Financial Performance – Attributable to MPLX

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18.2 25.1 26.7

30.5 28.9

43.8 39.9 40.2

0

10

20

30

40

50

4Q12 1Q13 2Q13 3Q13 4Q13 1Q14 2Q14 3Q14

$MM

Adjusted EBITDA

16.6

27.9 26.9 31.0 28.3

37.3 36.2 33.4

0

10

20

30

40

4Q12 1Q13 2Q13 3Q13 4Q13 1Q14 2Q14 3Q14

$MM

Distributable Cash Flow

Note: 4Q12 is the period October 31, 2012 to December 31, 2012

Select Balance Sheet and Financial Data

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($MM except ratio data) As of 9/30/14

Cash and cash equivalents 32.2

Total assets 1,194.3

Long-term debt(a) 265.0

Total equity 833.3

Consolidated total debt to consolidated EBITDA ratio (covenant basis)(b,c) 1.7x

Undrawn revolving credit agreement 245.0

(a) Includes amounts due within one year (b) Maximum covenant ratio <= 5.0 or 5.5 during the six month period following certain acquisitions (c) Based on last 12 months

Distribution Growth per Unit

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0.2625*

(MQD) 0.2725

0.2850 0.2975

0.3125 0.3275

0.3425 0.3575

0.20

0.22

0.24

0.26

0.28

0.30

0.32

0.34

0.36

4Q12 1Q13 2Q13 3Q13 4Q13 1Q14 2Q14 3Q14

$/U

nit

1.49x 1.37x

*Represents minimum quarter distribution (MQD) for 4Q12, actual $0.1769 equal to MQD prorated

Coverage Ratio 1.36x 1.25x 1.25x 1.38x 1.19x

IPO 10/31/2012

1st drop 5/1/2013 $100 MM

2nd drop 3/1/2014 $310 MM

1.20x

Appendix

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Adjusted EBITDA and Distributable Cash Flow Reconciliation from Net Income

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($MM) 4Q 2012* 1Q 2013 2Q 2013 3Q 2013 4Q 2013 1Q 2014 2Q 2014 3Q 2014

Net income 26.3 35.3 34.8 39.2 36.8 55.7 42.9 43.1

Less: Net income attributable to MPC-retained interest 13.2 17.7 16.2 17.7 16.6 21.5 14.1 14.0

Net income attributable to MPLX LP 13.1 17.6 18.6 21.5 20.2 34.2 28.8 29.1

Plus: Net income attributable to MPC-retained interest 13.2 17.7 16.2 17.7 16.6 21.5 14.1 14.0

Depreciation 7.9 11.7 11.9 12.7 12.6 12.6 12.4 12.5

Provision (benefit) for income taxes 0.1 - 0.1 0.4 (0.7) - 0.1 -

Non-cash equity-based compensation 0.1 0.2 0.3 0.3 0.6 0.4 0.5 0.5

Net interest and other financial costs 0.2 0.2 0.3 0.2 0.4 0.6 1.3 1.1

Adjusted EBITDA 34.6 47.4 47.4 52.8 49.7 69.3 57.2 57.2

Less: Adjusted EBITDA attributable to MPC-retained interest 16.4 22.3 20.7 22.3 20.8 25.5 17.3 17.0

Adjusted EBITDA attributable to MPLX LP 18.2 25.1 26.7 30.5 28.9 43.8 39.9 40.2

Plus: Current period deferred revenue for committed volume deficiencies(a)

2.1 4.7 2.9 5.1 6.0 7.7 6.9 7.8

Less: Net interest and other financial costs 0.3 0.3 0.3 0.5 0.4 0.8 1.3 1.4

Income taxes paid - - - - 0.1 - - -

Maintenance capital expenditures paid 3.4 1.5 2.3 4.0 3.9 1.9 3.2 5.8

Volume deficiency credits(b) - 0.1 0.1 0.1 2.2 11.5 6.1 7.4

Distributable cash flow attributable to MPLX LP 16.6 27.9 26.9 31.0 28.3 37.3 36.2 33.4

*For the period October 31, 2012 to December 31, 2012 (a) Deficiency payments included in distributable cash flow that are not included in net income or adjusted EBITDA. (b) Current period revenue related to volume deficiency credits generated in prior periods that are included in adjusted EBITDA but not distributable cash flow.

Adjusted EBITDA Reconciliation from Net Income

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($MM) 2013 3Q 2014

AnnualizedDec. 2015

AnnualizedNet income 146 172 304 Less: Net income attributable to MPC-retained interest

68 56 -

Net income attributable to MPLX LP 78 116 304 Plus: Net income attributable to MPC- retained interest 68 56 - Depreciation 49 50 71 Provision for income taxes - - 4 Non-cash equity-based compensation 1 2 - Net interest and other financial costs 1 4 71 Adjusted EBITDA 197 228 450 Less: Adjusted EBITDA attributable to MPC-retained interest

86 68 -

Adjusted EBITDA attributable to MPLX LP 111 160 450

MPC’s Currently Identified Eligible MLP EBITDA Sources of ~ $1.7 B Retained by MPC

59 MMBBL storage (tanks and caverns) 25 rail loading racks and 24 truck loading racks 7 owned and 11 non-owned docks 2 condensate splitter investments

27 owned and 2,138 leased 763 general service; 1,166 high pressure; 236 open-top hoppers

~ 5,400 miles of additional crude and products pipelines – Owns, leases or has an ownership interest in these pipelines – 31% of MPLX Pipe Line Holdings LP

Southern Access Extension, Sandpiper and Utica investments

Railcars

Pipelines

63 light product; ~ 23 MMBBL storage; 192 loading lanes 18 asphalt; ~ 4 MMBBL storage; 65 loading lanes Terminals

200 owned and 12 leased inland barges; 5.3 MMBBL capacity 17 owned and one leased inland towboats Marine

20 B gallons of fuels distribution volume –Existing MPC and Speedway volumes; ~ 17 B gallons refined products –Acquisition of Hess’ retail operations adds ~ 3 B gallons refined products

Fuels Distribution

Refineries New New

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