MPLX (NYSE:MPLX) has been an excellent income stock to own over the years. The master limited partnership (MLP) has raised its cash distribution to investors in each of the last 25 straight quarters. Further, those have been healthy increases -- the payout grew by 6.5% in the past year alone.

Moreover, it looks as though there will plenty of additional growth ahead for the midstream giant based on the major expansion initiatives it recently unveiled. Those moves make the stock, which is currently yielding 8.4%, an even more attractive option for income-seeking investors to consider buying this month.

The word dividends with a hand drawing an upward sloping arrow.

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A merger that makes sense

In early May, MPLX agreed to acquire its sibling, Andeavor Logistics (NYSE:ANDX), in a $14 billion deal. The company is only paying about a 1% premium for the MLP since their mutual parent is selling the units it owns at a discount to help facilitate the transaction. Because of that, the deal should be immediately accretive to cash flow. On top of that, MPLX will benefit from an improved financial profile thanks to the increased scale and diversification it will gain. The combined company will generate $4.1 billion of cash flow this year, which is enough to cover MPLX's high-yielding payout by a comfortable 1.4 times. That's well above the $2.8 billion in cash flow and 1.35 times coverage ratio MPLX posted last year.

Another benefit of the transaction is that it will improve the combined company's growth prospects. That's because MPLX can leverage Andeavor's oil gathering footprint in the Permian Basin to support the expansion of its export capabilities along the Gulf of Mexico. In addition, the company should be able to take advantage of its larger scale to capture additional high-return expansion opportunities.

Greenlighting new pipeline investments

MPLX followed up that needle-moving merger deal by agreeing to invest in two large-scale pipeline projects. The company recently signed a letter of intent to join Plains All American Pipeline (NYSE:PAA) and ExxonMobil (NYSE:XOM) on their Wink-to-Webster pipeline, which will move crude oil from the Permian Basin to the Gulf Coast. The company opted to invest in Wink-to-Webster after its partners in the planned Permian Gulf Coast pipeline abandoned that competing project. The Exxon/Plains pipeline should be in service by the first half of 2021. Not only will MPLX enjoy the cash flows from its investment in this high-return project, but it will support the company's export expansion plans along the Gulf Coast.

In addition, MPLX and its partners finally approved the construction of the Whistler Pipeline this month. That system, expected to go into service by the third quarter of 2021, will move natural gas from the Permian Basin to the Gulf Coast. Several energy companies initially pitched the project last summer, but it lost out to a rival pipeline after ExxonMobil signed on to move its gas via the other project. MPLX, however, stuck with Whistler, and was eventually able to secure enough customers to move forward with construction.

The company is also working with partners to develop a new natural gas liquids (NGLs) line from the Permian to the Gulf Coast. Approving that pipeline could also enable MPLX to move forward with the construction of facilities that would process those NGLs. Securing these projects would fuel even faster cash flow growth in the 2021 to 2022 time frame.

High yield and an even higher-octane growth rate

MPLX is one stock that income-seeking investors shouldn't overlook. Not only does it pay a well-supported 8.4%-yielding distribution, but it now has even better growth prospects. That improved profile makes it the top high-yield stock to consider buying this June in my opinion.