No one loves lower gasoline prices more than gas station owners. Sure they’re charging less, but so long as gas prices are dropping because oil’s getting cheaper, chances are their margins are fattening.

When prices are high and rising, filling stations inevitably get squeezed by suppliers jacking up their costs, while motorists fume, hunt for the cheapest gas in town and skip that soda from the station’s convenience store.

But when prices are falling, an entirely different dynamic takes hold. Pump prices decline slower than wholesale gasoline, because drivers stop being so picky. They might drive more, and definitely spend more on sundries at the mart. More sales at fatter margins would make any business owner happy.

This happy state of affairs has now persisted for months. But it was only when the stock market stopped skidding in mid-October that this idea seems to have occurred to numerous investors. Here’s what that’s done for the share price of CST Brands (NYSE: CST), the chain of filling stations and associated stores spun off by Valero (NYSE: VLO) and a recent Growth Portfolio addition:

And here’s Alimentation Couche-Tard (TSX: ATD-B), the corporate parent of the Circle K chain:

Unfortunately, that’s about it for gasoline retail pure plays. Many of the other major chains are owned by integrated oil majors or refiners, whose profits aren’t as dependent on retail margins.

In last month’s issue we noted that top-ranked Best Buy Energy Transfer Partners (NYSE: ETP) does, in fact, have a big presence in gasoline retailing. But that business recently accounted for only 17% of its diversified profits.

Recent portfolio pick Delek Logistics (NYSE: DKL) enjoys some indirect exposure to retail since it supplies fuel to its parent’s filling stations, and like ETP it has handily outperformed over the last month.

But we’ve been on the lookout for a more direct play on cheap gasoline, and we think we’ve found it in Global Partners (NYSE: GLP). This Northeast fuel dealer has evolved into a nationwide crude and fuel logistics play, but gas stations are a big and growing part of its appeal.

Following a series of acquisitions in recent years it now supplies a billion gallons of gasoline annually to more than 1,000 gas stations, including 126 it owns and operates and another 415 leased out or managed on commission. Sometime in the first quarter of next year Global Partners expects to close its recently announced acquisition of a filling station and convenience store chain from Warren Equities. At that point, the master limited partnership would be supplying gas to more than 1,500 stations from Maryland to Maine, and would own roughly half that total.

Source: Global Partners presentation

Distributing and retailing gasoline already accounts for just about half of Global Partners’ recent profit margin, with distribution earning twice as much as retailing. The margin from those two businesses was up 24% year-over-year in the third quarter, and the pending acquisition promises to improve those economics as added scale yields cost savings.

If that’s all there was to this story we probably wouldn’t be interested — after all, commodity prices and margins are fickle. If crude were to bounce back to $90 next month, some of the recent gains would almost certainly reverse. But Global Partners, which traces its origins to a one-truck heating oil delivery service started 81 years ago in Boston by the grandparents of the current CEO, is about more than just gas stations.

It’s also a crude and fuel wholesale and logistics business funneling sweet North Dakota crude to the east and west coasts (and one day soon heavy Canadian oil to the terminal it hopes to build on the Gulf Coast.) The east and west coasts lack sufficient pipeline connections to the interior where most of the domestic crude is produced these days. Global Partners loads oil trains at its two North Dakota terminals to fill that gap, and its margin on this wholesale operation expanded 32% year-over-year in the third quarter. In combination, the wholesale and the gasoline distribution segments make Global a crucial link between the North Dakota oilfields and coastal refineries, and between those refineries and motorists’ fuel tanks.

Source: Global Partners presentation

The lynchpin in this network is the intermodal crude and fuels terminal in Albany, NY, acquired from ExxonMobil in 2007 and since dramatically expanded to unload up to two 120-car trains a day bearing Bakken crude. Single-line service options from the Bakken via Burlington Northern Santa Fe or Canadian Pacific cut transit and offloading times and minimize logistics snags.

Here most of the oil Global ships from North Dakota is loaded onto Hudson River barges for delivery to refineries along the Eastern Seaboard. The facility is part of Global Partners’  leading Northeast terminal system with 9.2 million barrels of storage capacity.

Other shrewd acquisitions have followed, including the two North Dakota rail terminals with their own storage and pipeline links and the West Coast crude handling facility in Oregon, which also hosts a large ethanol plant set to start up in 2016.

The well-timed purchases of these assets, along with gas stations, at attractive prices suggest the Gulf Coast terminal Global plans to build on spec will also not lack for customers, especially considering the glut of Gulf Coast crude and the heavy concentration of nearby refining capacity, along with the likelihood of growth in oil exports.

It would have been relatively easy to cobble together a logistics empire like this by running up a big debt or by severely diluting one’s limited partners. Instead, Global Partners continues investing from the solid foundation of a strong balance sheet and ample retained profits.

Debt not counting a working capital credit facility is far from onerous at 2.6 times trailing EBITDA (adjusted earnings.) The partnership has just raised its 2014 EBITDA guidance by some 20%. So far this year, Global has produced more than two times as much distributable cash flow as it’s needed to cover its current 6.3% distribution yield. Distributions per unit have increased nearly 9% over the last year.

Investment risks include the partnership’s dependence on commodity product margins, the relative dearth of long-term, fixed-fee contracts, and speculative projects like the purchase of the Oregon facility and the planned construction of the one in Texas without long-term commitments from customers. But the steady gasoline distribution and retail business somewhat offsets this risk as does management’s excellent operational, strategic and financial track record.

Global Partners has strong, diversified growth prospects and a reasonable valuation at an enterprise value (market cap plus debt) multiple of less than 8 times trailing EBITDA. For the sake of comparison, Buckeye Partners (NYSE: BPL) is valued at 21 times trailing EBITDA for assets that have performed less impressively to this point.

We’re adding Global Partners to our Growth Portfolio. Buy GLP below $50.