SUMMARY

        This summary highlights selected information from this proxy statement/prospectus. You are urged to read carefully the entire proxy statement/prospectus and the other documents referred to in this proxy statement/prospectus because the information in this section does not provide all of the information that might be important to you with respect to the merger agreement, the merger and the other matters being considered at the special meeting. See "Where You Can Find More Information." Each item in this summary refers to the page of this proxy statement/prospectus on which that subject is discussed in more detail.

The Parties (See page 36)

        EQM is a growth-oriented limited partnership formed by EQT to own, operate, acquire and develop midstream assets in the Appalachian Basin. EQM provides midstream services to EQT and multiple third parties in Pennsylvania, West Virginia and Ohio through its two primary assets: the gathering system, which delivers natural gas from wells and other receipt points to transmission pipelines, and the transmission and storage system, which delivers gas to local demand users and interstate pipelines for access to demand markets. EQM provides a substantial majority of its natural gas gathering, transmission and storage services under contracts with long-term, firm reservation and/or usage fees.

        RMP is a growth-oriented limited partnership originally formed by Rice Energy Inc. (Rice Energy) to own, operate, develop and acquire midstream assets in the Appalachian Basin. RMP operates in two business segments, which are managed separately due to their distinct operational differences: (i) gathering and (ii) water. RMP's natural gas gathering assets consist of natural gas gathering systems and associated compression that service EQT and other third-party producers in the dry gas core of the Marcellus Shale in southwestern Pennsylvania. RMP's water services assets consist of water pipelines, impoundment facilities, pumping stations, take point facilities and measurement facilities, which are used to support well completion activities and to collect and recycle or dispose of flowback and produced water for EQT and other third-party producers in Washington and Greene Counties, Pennsylvania and Belmont County, Ohio. RMP provides its services under long-term, fee-based contracts, primarily to EQT and its affiliates.

The Merger (See page 42)

        Subject to the terms and conditions of the merger agreement and in accordance with Delaware law, the merger agreement provides for the merger of Merger Sub with and into RMP, with RMP surviving the merger as a wholly owned subsidiary of EQM, at which time RMP will no longer be publicly traded.

The GP Merger (See page 42)

        Subject to the terms and conditions of the merger agreement and in accordance with Delaware law, and concurrently with (or as soon as practicable after) the merger, GP Merger Sub will merge with and into RMP GP (the GP merger and, together with the merger, the mergers). RMP GP will survive the GP merger and remain the general partner of RMP.

Merger Consideration (See page 82)

        The merger agreement provides that, at the effective time, each RMP common unit issued and outstanding or deemed issued and outstanding as of immediately prior to the effective time will be converted into the right to receive 0.3319 EQM common units.

Treatment of RMP Phantom Units (See page 82)

        At the effective time, each award of phantom units in respect of RMP common units (each, an RMP Phantom Unit Award) that is outstanding immediately prior to the effective time will be fully vested and converted into the right to receive the merger consideration, less applicable tax withholding, in respect of each RMP common unit subject thereto.

Treatment of General Partner Interest and Incentive Distribution Rights (See pages 73 and 82)

        Following the mergers, the surviving entity in the GP merger will hold the entire general partner interest in RMP and will retain the rights and duties of the general partner of RMP. The merger agreement also provides that, at the effective time, all of the RMP IDRs outstanding immediately prior to the effective time will be cancelled.

The Special Meeting; Units Entitled to Vote; Required Vote (See page 37)

        Meeting.    The special meeting will be held at EQT Plaza, 625 Liberty Avenue, Pittsburgh, Pennsylvania 15222, on July 20, 2018 at 8:00 a.m., local time. At the special meeting, RMP unitholders will be asked to vote on the following proposal:

•

Merger proposal:  To approve the merger agreement, a copy of which is attached as Annex A to this proxy statement/prospectus, and the merger.

        Record Date.    Only RMP unitholders of record at the close of business on June 7, 2018 will be entitled to receive notice of and to vote at the special meeting. As of the close of business on the record date, there were approximately 102,323,796 RMP common units outstanding and entitled to vote at the meeting. Each holder of RMP common units is entitled to one vote for each common unit owned as of the record date.

        Required Vote.    To approve the merger proposal, holders of at least a majority of the outstanding RMP common units must vote in favor of such proposal. RMP cannot complete the merger unless its unitholders approve the merger proposal. Because approval is based on the affirmative vote of at least a majority of the outstanding RMP common units, an RMP unitholder's failure to vote, an abstention from voting or the failure of an RMP unitholder who holds his or her units in "street name" through a broker or other nominee to give voting instructions to such broker or other nominee will have the same effect as a vote "AGAINST" approval of the merger proposal.

        Postponements and Adjournments.    Pursuant to the RMP partnership agreement, RMP GP may postpone the special meeting one or more times for any reason by giving notice to each RMP unitholder entitled to vote at the meeting so postponed of the place, date and hour at which such postponed meeting would be held not fewer than two days before the date of the special meeting. In addition, the special meeting may be adjourned by RMP GP one or more times for any reason, including the failure of a quorum to be present at the special meeting with respect to the merger proposal or the failure of the merger proposal to receive sufficient votes for approval. No vote of RMP unitholders is required for any adjournment.

        Unit Ownership of and Voting by RMP's Directors, Executive Officers and Affiliates.    As of June 7, 2018, RMP's directors and executive officers and affiliates (including EQT and its subsidiaries) beneficially owned and had the right to vote 28,896,793 RMP common units at the special meeting, which represent 28.2% of the RMP common units entitled to vote at the special meeting. It is expected that RMP's directors and executive officers will vote their units "FOR" the approval of the merger agreement and the merger, although none of them has entered into any agreement requiring them to do so. Additionally, under the terms of the merger agreement, EQT has agreed to vote all of the RMP common units owned beneficially or of record by EQT or its subsidiaries in favor of the approval of the merger proposal.

Recommendation of the RMP Board and the RMP Conflicts Committee; Reasons for the Merger (See page 50)

        The RMP Board and the RMP Conflicts Committee recommend that RMP unitholders vote "FOR" the approval of the merger agreement and the merger.

        In the course of reaching their decisions to approve the merger agreement and the transactions contemplated by the merger agreement, the RMP Conflicts Committee and the RMP Board considered a number of factors in their deliberations. For a more complete discussion of these factors, see "The Merger—Recommendation of the RMP Board and the RMP Conflicts Committee; Reasons for the Merger."

Opinion of the Financial Advisor to the RMP Conflicts Committee (See page 55)

        In connection with the proposed transaction, the RMP Conflicts Committee received, on April 25, 2018, an oral opinion from Jefferies LLC (Jefferies), which was subsequently confirmed in a written opinion, dated April 25, 2018, from Jefferies, as to the fairness, as of the date of the opinion and based upon and subject to the qualifications, limitations and assumptions stated therein, of the exchange ratio, from a financial point of view, to RMP and the unaffiliated RMP unitholders.

The IDR Purchase and the Drop-Down Transactions (See page 104 and page 95)

        On April 25, 2018, concurrently with entering into the merger agreement, EQT and/or its affiliates entered into (i) the IDR purchase agreement, pursuant to which, subject to the terms and conditions thereof, EQGP acquired all of the outstanding RMP IDRs from RMGH in exchange for an aggregate of 36,293,766 EQGP common units and (ii) the drop-down agreement, pursuant to which, subject to the terms and conditions thereof, EQM acquired EQT's interests in certain midstream businesses including Rice West Virginia, Rice Olympus and Strike Force Holdings in exchange for an aggregate of 5,889,282 EQM common units and aggregate cash consideration of $1.15 billion. The IDR purchase and the drop-down transactions were completed on May 22, 2018.

        Also on April 25, 2018, EQM, EQM Gathering, Gulfport and an affiliate of Gulfport entered into a Purchase and Sale Agreement pursuant to which EQM agreed to acquire the 25% limited liability company interest in Strike Force Midstream not owned by Strike Force Holdings for $175 million in cash, which was completed on May 1, 2018.

Financing of the Transactions (See page 70)

        The merger is not subject to a financing condition. On April 25, 2018, EQM entered into a 364-Day Term Loan Agreement (the Term Loan Agreement) among EQM, Wells Fargo Bank, National Association, as Administrative Agent, and the lenders (the Lenders) and agents parties thereto, providing for a $2.5 billion 364-day unsecured multi-draw term loan facility (the Term Loan Facility).

        The Term Loan Agreement provides for borrowings by EQM of (i) up to $300 million of the commitments under the Term Loan Facility (the Merger Availability) in connection with, and to fund, the consummation of the merger, (ii) up to $1 billion of the commitments under the Term Loan Facility in connection with, and to fund, the consummation of the drop-down transactions (the Drop-Down Availability), and (iii) up to an additional $1.2 billion of commitments under the Term Loan Facility (the General Availability) for a variety of specified purposes, including to fund the consummation of the merger and/or the drop-down transactions. The Lenders' obligation to fund such commitments under the Term Loan Facility is subject to several conditions as set forth in the Term Loan Agreement, including, in the case of certain borrowings in connection with the merger, delivery of a certificate certifying that EQM expects the merger to be consummated within one business day.

        As of May 17, 2018, the General Availability was reduced by $825 million, of which $513 million was used to repay borrowings outstanding under EQM's existing $1 billion revolving credit facility. On

May 22, 2018, substantially concurrently with the consummation of the drop-down transactions, EQM borrowed all $1 billion of the Drop-Down Availability. As of June 14, 2018, $375 million of the General Availability and all $300 million of the Merger Availability remained available for borrowing pursuant to the terms of the Term Loan Agreement. Unused commitments under the Term Loan Facility will terminate automatically on December 31, 2018. The Term Loan Agreement includes mandatory prepayment and commitment reduction requirements related to the receipt by EQM of net cash proceeds from certain debt transactions, equity issuances, asset sales, and joint venture distributions.

        EQM expects to use proceeds from future borrowings under the Term Loan Facility to, among other things, (i) substantially concurrently with the closing of the merger, refinance all existing debt for borrowed money of RMP and its subsidiaries, including to repay and terminate, as applicable, all amounts and commitments outstanding under the RMP existing credit facility (as defined in "The Merger Agreement—Conduct of Business Pending Consummation of the Merger"), and (ii) pay any fees, commissions and expenses incurred in connection with the foregoing.

No EQM Unitholder Approval Required (See page 70)

        EQM unitholders are not required to approve the merger agreement or approve the merger or the issuance of EQM common units in connection with the merger.

Directors and Executive Officers of EQM GP After the Merger (See page 70)

        No changes are anticipated to the identity of the directors and executive officers of EQM GP as a result of the merger.

Ownership of EQM After the Merger (See page 72)

        EQM will issue approximately 34.0 million EQM common units to former RMP unitholders pursuant to the merger agreement. Based on the number of EQM common units outstanding as of June 15, 2018, immediately following the completion of the merger, EQM expects to have approximately 120.5 million common units outstanding. RMP unitholders are therefore expected to hold approximately 28.2% of the aggregate number of EQM common units outstanding immediately after the merger and approximately 27.9% of EQM's total units of all classes. Holders of EQM common units (similarly to holders of RMP common units) are not entitled to elect EQM GP or the members of the board of directors of EQM GP (the EQM Board) and have only limited voting rights on matters affecting EQM's business.

Interests of Directors and Executive Officers of RMP GP in the Merger (See page 66)

        The directors and executive officers of RMP GP have interests in the merger that are different from, or in addition to, the interests of RMP unitholders generally. The members of the RMP Board were aware of and considered these interests, among other matters, in evaluating and negotiating the merger agreement and the merger, and in recommending to RMP's unitholders that the merger agreement be approved.

        These interests include:

•

Certain directors and executive officers of RMP GP are also directors, executive officers and/or employees of EQT, EQM GP and/or the EQGP general partner;



•

Certain members of the RMP Board hold RMP Phantom Unit Awards, which immediately prior to the effective time would fully vest and convert into the right to receive the merger consideration; and

•

The directors and executive officers of RMP GP are entitled to continued indemnification and insurance coverage under the RMP partnership agreement, the merger agreement and the limited liability company agreement of RMP GP.

Interests of EQT in the Merger (See page 69)

        EQT holds a controlling ownership interest in RMP. EQT controls RMP through EQT's ownership of RMP GP, which is the general partner of RMP. RMP GP owns 100% of the general partner interest in RMP. EQT also owns an approximately 6.7% limited partner interest in EQM through Rice Midstream Holdings, 100% of the outstanding limited liability company interests in the EQGP general partner, and an approximately 91.3% limited partner interest in EQGP, and EQGP owns 100% of the outstanding limited liability company interests in EQM GP which owns an approximately 1.6% general partner interest in EQM, an approximately 24.8% limited partner interest in EQM and all of the EQM IDRs and RMP IDRs. EQT has different economic interests in the merger than RMP unitholders generally due to, among other things, EQT's ongoing ownership of the general partner interest and incentive distribution rights through EQGP in EQM following the merger. In addition, EQT and/or wholly owned subsidiaries of EQT are party to the IDR purchase and the drop-down transactions, each of which was completed on May 22, 2018, with such completion having been a condition to the parties' obligations to complete the merger (see "—The IDR Purchase and the Drop-Down Transactions").

        Under the terms of the merger agreement, EQT has agreed to vote all of the RMP common units owned beneficially or of record by EQT and its subsidiaries in favor of the approval of the merger agreement and the merger and the approval of any actions required in furtherance thereof.

Risk Factors Relating to the Merger and Ownership of EQM Common Units (See page 27)

        RMP unitholders should consider carefully all the risk factors together with all of the other information included or incorporated by reference in this proxy statement/prospectus before deciding how to vote. Risks relating to the merger and ownership of EQM common units are described in the section titled "Risk Factors." Some of these risks include, but are not limited to, those described below:

•

Because the market price of EQM common units will fluctuate prior to the consummation of the merger, RMP unitholders cannot be sure of the market value of the EQM common units they will receive as merger consideration relative to the value of RMP common units they exchange.



•

EQM and RMP may be unable to obtain the regulatory clearances required to complete the merger or, in order to do so, EQM and RMP may be required to comply with material restrictions or satisfy material conditions.



•

The merger agreement contains provisions that limit RMP's ability to pursue alternatives to the merger, which could discourage a potential competing acquirer of RMP from making a favorable alternative transaction proposal and, in specified circumstances, including if the merger agreement is terminated due to an adverse recommendation change having occurred, could require RMP to pay a termination fee to EQM of $63.4 million.



•

Directors and officers of RMP have certain interests that are different from those of RMP unitholders generally.



•

RMP unitholders will have a reduced ownership in the combined organization after the merger.



•

EQM common units to be received by RMP unitholders as a result of the merger have different rights from RMP common units.



•

No ruling has been requested with respect to the U.S. federal income tax consequences of the merger.

•

The intended U.S. federal income tax consequences of the merger are dependent upon EQM and RMP being treated as partnerships for U.S. federal income tax purposes.



•

EQT is the ultimate parent company of each of EQM, RMP, EQM GP, EQGP, RMP GP and the EQGP general partner. This may result in conflicts of interest.



•

EQM unitholders have limited voting rights and are not entitled to elect EQM's general partner or the directors of EQM's general partner.

Material U.S. Federal Income Tax Consequences of the Merger (See page 116)

        Tax matters associated with the merger are complicated. The U.S. federal income tax consequences of the merger to an RMP unitholder will depend, in part, on such unitholder's particular circumstances. The tax discussions in this proxy statement/prospectus are limited to the U.S. federal income tax consequences generally applicable to U.S. holders that hold their RMP units as capital assets and acquired their RMP units in exchange for cash, and these discussions have only limited application to other unitholders, including those subject to special rules under the U.S. federal income tax laws. RMP unitholders are urged to consult their tax advisors for a full understanding of the U.S. federal, state, local and foreign tax consequences of the merger that will be applicable to them.

        For U.S. federal income tax purposes, the merger is intended to qualify as a "merger" of RMP and EQM within the meaning of Treasury Regulations promulgated under Section 708 of the Code, with EQM treated as the continuing partnership and RMP as the terminated partnership for U.S. federal income tax purposes following the merger.

        It is a condition to the parties' respective obligations to complete the merger that (1) EQM receive an opinion of Baker Botts L.L.P., dated as of the date of the closing of the merger, to the effect that (i) at least 90% of the gross income of EQM for all of the calendar year that immediately precedes the calendar year that includes the date of the closing of the merger and each calendar quarter of the calendar year that includes the date of the closing of the merger for which the necessary financial information is available is from sources treated as "qualifying income" within the meaning of Section 7704(d) of the Code and (ii) at least 90% of the combined gross income of each of EQM and RMP for all of the calendar year that immediately precedes the calendar year that includes the date of the closing of the merger and each calendar quarter of the calendar year that includes the date of the closing of the merger for which the necessary financial information is available is from sources treated as "qualifying income" within the meaning of Section 7704(d) of the Code and (2) RMP receive an opinion of Baker Botts L.L.P., dated as of the date of the closing of the merger, to the effect that at least 90% of the gross income of RMP for all of the calendar year that immediately precedes the calendar year that includes the date of the closing of the merger and each calendar quarter of the calendar year that includes the date of the closing of the merger for which the necessary financial information is available is from sources treated as "qualifying income" within the meaning of Section 7704(d) of the Code.

        It is a condition to EQM's obligation to complete the merger that it receive a written opinion of Baker Botts L.L.P., dated as of the date of the closing of the merger, to the effect that for U.S. federal income tax purposes (i) EQM should not recognize any income or gain as a result of the merger, and (ii) no gain or loss should be recognized by holders of EQM common units or other partnership interests in EQM as a result of the merger (other than any gain resulting from any decrease in partnership liabilities pursuant to Section 752 of the Code).

        It is a condition to RMP's obligation to complete the merger that it receive an opinion of Baker Botts L.L.P., dated as of the date of the closing of the merger, to the effect that for U.S. federal income tax purposes (i) RMP should not recognize any income or gain as a result of the merger and (ii) no gain or loss should be recognized by holders of RMP common units or other partnership interests in RMP as a result of the merger (other than any gain resulting from (A) any actual or

constructive distribution of cash or other property or (B) any decrease in partnership liabilities pursuant to Section 752 of the Code).

        These opinions will be based on representations made by RMP, EQM and others and on customary factual assumptions, as well as certain covenants and undertakings. Opinions of counsel are subject to certain limitations and are not binding on the Internal Revenue Service (the IRS) or any court. RMP and EQM have not sought and do not intend to seek any rulings from the IRS regarding any matters relating to the merger.

        Accordingly, in general, the receipt of EQM common units in respect of RMP common units should not result in the recognition of taxable gain or loss to RMP unitholders. Any actual or deemed receipt of cash by an RMP unitholder (including as the result of a net reduction in the amount of nonrecourse liabilities allocated to such RMP unitholder) will result in the recognition of taxable gain if such receipt exceeds the adjusted tax basis in the RMP common units surrendered in the merger.

        RMP unitholders should read the section entitled "Material U.S. Federal Income Tax Consequences of the Merger" for a more complete discussion of the U.S. federal income tax consequences of the merger. Tax matters can be complicated, and the tax consequences to a particular holder will depend on such holder's facts and circumstances. RMP unitholders should consult their own tax advisors to determine the specific tax consequences to them of the merger.

Material U.S. Federal Income Tax Consequences of EQM Common Unit Ownership (See page 120)

        Each RMP unitholder who becomes an EQM unitholder as a result of the merger will be required to report on its U.S. federal income tax return such unitholder's distributive share of EQM's income, gains, losses, deductions and credits. In addition to U.S. federal income taxes, such a holder will be subject to other taxes, including state and local income taxes, unincorporated business taxes, and estate, inheritance or intangibles taxes that may be imposed by the various jurisdictions in which EQM conducts business or owns property or in which the unitholder is a resident. Please read "Material U.S. Federal Income Tax Consequences of EQM Common Unit Ownership."

Accounting Treatment of the Merger (See page 71)

        In accordance with the guidance under Accounting Standards Codification Topic 805: Business Combinations, the merger will be accounted for as a reorganization of entities under common control. The assets and liabilities of RMP will be recorded by EQM at EQT's historical cost basis, which includes a step-up basis resulting from EQT's preliminary purchase price accounting for its acquisition of Rice Energy.

Listing of EQM Common Units; Delisting and Deregistration of RMP Common Units (See page 72)

        EQM common units are currently listed on the NYSE under the ticker symbol "EQM." It is a condition to closing that the EQM common units to be issued in the merger to RMP unitholders be approved for listing on the NYSE, subject to official notice of issuance. Following the consummation of the merger, it is expected that EQM common units will continue to be listed on the NYSE under the symbol "EQM."

        RMP common units are currently listed on the NYSE under the ticker symbol "RMP." If the merger is completed, RMP common units will cease to be listed on the NYSE and will be deregistered under the Exchange Act.

No Dissenters' Rights or Appraisal Rights (See page 70)

        Neither dissenters' rights nor appraisal rights are available in connection with the merger under the Delaware LP Act, the merger agreement or the RMP partnership agreement.

Conditions to Consummation of the Merger (See page 74)

        EQM and RMP currently expect to complete the merger shortly following the conclusion of the meeting, subject to receipt of required RMP unitholder approval and regulatory approvals and clearances and to the satisfaction or waiver of the other conditions to the transactions contemplated by the merger agreement described below.

        As more fully described in this proxy statement/prospectus, the parties' obligations to complete the transactions contemplated by the merger agreement depend on a number of closing conditions being satisfied or, where legally permissible, waived, including the following:

•

the merger agreement and the merger must have been approved by the affirmative vote or consent of the holders of at least a majority of the outstanding RMP common units;



•

any waiting period applicable to the merger under the Hart-Scott-Rodino Antitrust Improvements Act of 1976, as amended (the HSR Act), must have been terminated or expired;



•

no law, injunction, judgment or ruling enacted, promulgated, issued, entered, amended or enforced by any governmental authority will be in effect enjoining, restraining, preventing or prohibiting the consummation of the transactions contemplated by the merger agreement or making the consummation of such transactions illegal;



•

the registration statement of which this proxy statement/prospectus forms a part must have been declared effective by the SEC and must not be subject to any stop order or proceedings initiated or threatened by the SEC;



•

the EQM common units to be issued in the merger must have been approved for listing on the NYSE, subject to official notice of issuance;



•

RMP having received from Baker Botts L.L.P., tax counsel to RMP, certain written opinions regarding certain U.S. federal income tax matters, as described under "The Merger Agreement—Conditions to Consummation of the Merger";



•

EQM having received from Baker Botts L.L.P., tax counsel to EQM, certain written opinions regarding certain U.S. federal income tax matters, as described under "The Merger Agreement—Conditions to Consummation of the Merger";



•

closing of the IDR purchase having occurred (which closing did occur on May 22, 2018);



•

closing of the drop-down transactions having occurred or the parties to the drop-down agreement being ready, willing and able to complete the drop-down transactions substantially simultaneously with the closing of the merger (which closing did occur on May 22, 2018); and



•

subject to certain materiality standards, the representations and warranties of the other applicable parties to the merger agreement being true and correct, such parties having performed their obligations under the merger agreement, and the receipt of an officer's certificate certifying the foregoing.

Regulatory Approvals and Clearances Required for the Merger (See page 71)

        The completion of the merger may be subject to antitrust clearance in the United States. Under the HSR Act, if applicable, the merger cannot be completed until EQT (as the ultimate parent entity of EQM) and RMP have filed their respective notification and report forms with the Federal Trade Commission (the FTC) and the Antitrust Division of the United States Department of Justice (the DOJ), and until the applicable waiting period has expired or been terminated. Both EQT and RMP made their HSR filings on June 1, 2018. Early termination of the waiting period was granted on June 19, 2018. See "The Merger—Regulatory Approvals and Clearances Required for the Merger."

No Solicitation by RMP of Alternative Proposals (See page 78)

        The merger agreement contains detailed provisions prohibiting RMP from seeking an alternative proposal (as defined under "The Merger Agreement—RMP Unitholder Approval") to the merger. As described in more detail elsewhere in this proxy statement/prospectus, under these "no solicitation" provisions, RMP has agreed, among other things, that it will not solicit, initiate or knowingly encourage any inquiries or any proposals that constitute or could reasonably be expected to lead to an alternative business combination proposal. Notwithstanding these restrictions, the merger agreement provides that, under specified circumstances at any time prior to RMP unitholders voting in favor of approving the merger agreement, RMP may furnish information, including confidential information, with respect to it and its subsidiaries to, and participate in discussions or negotiations with, any third party that makes an unsolicited written alternative proposal that the RMP Board (upon the recommendation of the RMP Conflicts Committee) believes is bona fide so long as (after consultation with its financial advisors and outside legal counsel) the RMP Board (upon the recommendation of the RMP Conflicts Committee) determines in good faith that (i) such alternative proposal constitutes or could reasonably be expected to lead to or result in a superior proposal (as defined under "The Merger Agreement—No Solicitation by RMP of Alternative Proposals"), (ii) failure to furnish such information or participate in such discussions would be inconsistent with the RMP Board's duties under applicable law as modified by the RMP partnership agreement and (iii) such alternative proposal did not result from a willful breach of the no solicitation provisions in the merger agreement.

        RMP has also agreed in the merger agreement that it will promptly notify EQM of any alternative proposal and keep EQM reasonably informed of all material developments affecting the status and terms of any such alternative proposal and of the status of any associated discussions or negotiations.

Change in RMP Board Recommendation (See page 80)

        The merger agreement provides that RMP will not withdraw, modify or qualify, in a manner adverse to EQM, the recommendation of the RMP Board and the RMP Conflicts Committee that RMP's unitholders approve the merger agreement and the merger. However, subject to the satisfaction of specified conditions in the merger agreement, the RMP Board and the RMP Conflicts Committee may, at any time prior to the approval of the merger agreement by the RMP unitholders, effect an adverse recommendation change in response to either (i) an unsolicited alternative proposal constituting a superior proposal or (ii) a changed circumstance that was not known to or reasonably foreseeable by the RMP Board prior to the date of the merger agreement, in each case if the RMP Board, upon the recommendation of the RMP Conflicts Committee and after consultation with its outside legal counsel and financial advisors, determines in good faith that the failure to take such action would be inconsistent with its duties under applicable law as modified by the RMP partnership agreement.

Termination of the Merger Agreement (See page 83)

        The merger agreement may be terminated at any time prior to the effective time:

•

by mutual written consent of EQM and RMP;



•

by either EQM or RMP:



•

if the merger has not been consummated on or before December 31, 2018 (the outside date);



•

if any governmental authority has issued a final and nonappealable law or injunction prohibiting the merger;



•

If the drop-down agreement or the IDR purchase agreement has been terminated;

•

if the RMP unitholders do not approve the merger agreement and the merger at the special meeting; or



•

if there is a breach by the other party of any of its representations, warranties, covenants or agreements in the merger agreement such that certain closing conditions would not be satisfied, or if capable of being cured, such breach has not been cured within 30 days following delivery of written notice of such breach, subject to certain exceptions; and



•

by EQM:



•

if an adverse recommendation change by the RMP Board or the RMP Conflicts Committee has occurred prior to the RMP unitholders special meeting; or



•

if prior to the approval of the merger agreement by RMP unitholders, RMP is in willful breach of its obligations to (i) duly call, give notice of, convene and hold a special meeting of RMP unitholders for the purpose of obtaining unitholder approval of the merger agreement and the merger, use its reasonable best efforts to solicit proxies from the RMP unitholders in favor of such approval and, through the RMP Board and the RMP Conflicts Committee, recommend the approval of the merger agreement and the merger to RMP unitholders or (ii) comply with its non-solicitation obligations, in each case, subject to certain exceptions.

Expenses (See page 85)

        Generally, all fees and expenses incurred in connection with the transactions contemplated by the merger agreement will be the obligation of the party incurring such fees and expenses. However, following a termination of the merger agreement in specified circumstances, RMP will be required to pay all of the reasonably documented out-of-pocket expenses incurred by EQM and, under certain other specified circumstances, EQM will be required to pay all of the reasonably documented out-of-pocket expenses incurred by RMP, in each case, in connection with the merger agreement and the transactions contemplated thereby, up to a maximum amount of $5 million.

Termination Fee (See page 85)

        Following termination of the merger agreement under specified circumstances, including due to an adverse recommendation change having occurred, RMP will be required to pay EQM a termination fee of $63.4 million, less any expenses of EQM previously reimbursed by RMP to EQM pursuant to the merger agreement.

Comparison of Rights of EQM Unitholders and RMP Unitholders (See page 142)

        RMP unitholders will own EQM common units following the completion of the merger, and their rights associated with those EQM common units will be governed by the First Amended and Restated Agreement of Limited Partnership of EQT Midstream Partners, LP, as amended (the EQM partnership agreement), which differs in some respects from the RMP partnership agreement, and the Delaware LP Act.

Selected Historical Combined Financial Data of EQM

        The following table presents EQM's selected combined historical financial information that has been derived from (1) EQM's audited combined financial statements as of and for the years ended December 31, 2017, 2016 and 2015 and for the year ended December 31, 2014, (2) EQM's unaudited combined financial statements as of December 31, 2014 and 2013 and for the year ended December 31, 2013 and (3) EQM's unaudited combined financial statements as of and for the three months ended March 31, 2018 and 2017. The information set forth below is only a summary and is not necessarily indicative of future results nor does it include the effects of the merger. You should read this information together with EQM's combined financial statements, the related notes and the sections entitled "Management's Discussion and Analysis of Financial Condition and Results of Operations" in EQM's Current Report on Form 8-K filed with the SEC on June 12, 2018 for the year ended December 31, 2017 and quarter ended March 31, 2018 which is incorporated into this proxy statement/prospectus by reference. In EQM's view, the unaudited combined financial data of EQM as of and for the three months ended March 31, 2018 and 2017 contain all normal, recurring adjustments necessary for fair presentation of EQM's financial position and results of operations. The selected balance sheet data as of March 31, 2017 has been derived from EQM's unaudited combined financial statements as of March 31, 2017, which have not been incorporated into this proxy statement/prospectus by reference. For more information, refer to "Where You Can Find More Information."

Selected Historical Consolidated Financial Data of RMP

        The following table presents RMP's selected consolidated historical financial information that has been derived from (1) RMP's audited consolidated financial statements for the periods November 13, 2017 to December 31, 2017 and January 1, 2017 to November 12, 2017, as of December 31, 2017 and as of and for the years ended December 31, 2016, 2015, 2014 and 2013, and (2) RMP's unaudited consolidated financial statements as of and for the three months ended March 31, 2018 and 2017. The information set forth below is only a summary and is not necessarily indicative of future results nor does it include the effects of the mergers. You should read this information together with RMP's consolidated financial statements, the related notes and the sections entitled "Management's Discussion and Analysis of Financial Condition and Results of Operations" in RMP's Annual Report on Form 10-K as of and for the year ended December 31, 2017 filed on February 15, 2018, and RMP's Quarterly Report on Form 10-Q for the quarter ended March 31, 2018 filed on April 26, 2018, each of which is incorporated into this proxy statement/prospectus by reference. In RMP's view, the unaudited consolidated financial data of RMP as of and for the three months ended March 31, 2018 and 2017 contain all normal, recurring adjustments necessary for fair presentation of RMP's financial position and results of operations. The selected balance sheet data as of March 31, 2017 has been derived from RMP's unaudited consolidated financial statements as of March 31, 2017, which have not been incorporated into this proxy statement/prospectus by reference. For more information, refer to "Where You Can Find More Information."

Selected Unaudited Pro Forma Condensed Combined Financial Information

        The following selected unaudited pro forma condensed combined financial information gives effect to the mergers, the drop-down transactions and the Gulfport transaction (the pro forma events) and the related financings as if they occurred on (i) January 1, 2017 in the case of the unaudited pro forma statement of combined operations for the three months ended March 31, 2018 and for the year ended December 31, 2017 and (ii) March 31, 2018 in the case of the unaudited pro forma condensed combined balance sheet.

        The following selected unaudited pro forma condensed combined financial information has been prepared for illustrative purposes only and is not necessarily indicative of what the combined company's financial position or results of operations actually would have been had the pro forma events occurred as of the dates indicated. In addition, the unaudited pro forma condensed combined financial information does not purport to project the future financial position or operating results of the combined company. Future results may vary significantly from the results reflected because of various factors, including those discussed in the section entitled "Risk Factors." The following selected unaudited pro forma condensed combined financial information should be read in conjunction with the

section titled "EQT Midstream Partners, LP Unaudited Pro Forma Condensed Combined Financial Statements" and related notes included in this proxy statement/prospectus.

Comparative Historical and Unaudited Pro Forma Per Unit Financial Information

        The following tables present EQM's and RMP's historical and pro forma per unit data for the year ended December 31, 2017 and the three months ended March 31, 2018. Except for the historical information for the year ended December 31, 2017, the information provided in the table below is unaudited. This information should be read together with the historical combined and consolidated financial statements and related notes of EQM and RMP filed by each with the SEC, and incorporated by reference in this proxy statement/prospectus, and with the unaudited pro forma condensed combined financial statements included in the section entitled "EQT Midstream Partners, LP Unaudited Pro Forma Condensed Combined Financial Statements" and related notes beginning on page 106. For more information, refer to "Where You Can Find More Information."

        The following selected unaudited pro forma condensed combined financial information gives effect to the pro forma events as if they occurred on (i) January 1, 2017 in the case of the unaudited pro forma statement of combined operations for the three months ended March 31, 2018 and for the year ended December 31, 2017 and (ii) March 31, 2018 in the case of the unaudited pro forma condensed combined balance sheet. The pro forma information is presented for illustrative purposes only and is not necessarily indicative of the operating results or financial position that would have occurred if the merger and related transactions had been completed as of the beginning of the periods presented, nor is it necessarily indicative of the future operating results or financial position of the combined company.

        The historical book value per unit is computed by dividing total equity by the number of common and subordinated units outstanding, as applicable, at the end of the period. Pro forma net income per limited partner unit is determined by dividing the pro forma net income that would have been allocated, in accordance with the net income and loss allocation provisions of the partnership agreement, to the unitholders under the two-class method, after deducting the general partner's interest in the pro forma net income in addition to giving effect to incentive distributions allocable to the general partner, by the weighted average number of common units outstanding for the period, assuming the closing of the transactions described in Note 2 of the "EQT Midstream Partners, LP Unaudited Pro Forma Condensed Combined Financial Statements" occurred on January 1, 2017. The pro forma book value per unit of the combined company is computed by dividing total pro forma equity by the pro forma number of common units expected to be outstanding at the end of the period.

Comparative Per Unit Market Price and Distribution Information

EQM Market Price and Distribution Information

        EQM's common units are listed on the NYSE under the symbol "EQM." The following table sets forth the high and low market prices per EQM common unit and the cash distributions paid per EQM common unit during the periods indicated as reported on the NYSE.

        As the market price per EQM common unit may fluctuate between the date of this document and the date of the proposed merger's completion, you should supplement the above with current market prices through the date of the proposed merger's completion.

RMP Market Price and Distribution Information

        RMP's common units are listed on the NYSE under the symbol "RMP." The following table sets forth the high and low market prices per RMP common unit and the cash distributions paid per RMP common unit during the periods indicated as reported on the NYSE.

        As the market price per RMP common unit may fluctuate between the date of this document and the date of the proposed merger's completion, you should supplement the above with current market prices through the date of the proposed merger's completion.