Honestly, the skyline in Houston is changing faster than most people can keep up with. If you’ve spent any time driving through the Energy Corridor or looking up at the glassy towers in Uptown, you probably know the Marathon name. But there is a massive detail people are missing.
As of late 2024, Marathon Oil Company in Houston TX technically ceased to exist as an independent entity.
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ConocoPhillips swallowed them up in an all-stock deal valued at a staggering $22.5 billion. It’s one of those "end of an era" moments that feels personal to Houstonians because Marathon had been such a fixture of the city since moving its headquarters here from Ohio back in 1990.
The ConocoPhillips Merger: What Actually Happened?
It wasn't just a friendly handshake. This was a calculated move to dominate the U.S. shale market. ConocoPhillips didn't just want the name; they wanted the dirt. Specifically, the acreage. By grabbing Marathon, ConocoPhillips added roughly 2 billion barrels of resources to their inventory.
Most of this land is in the "big three" basins:
- The Delaware Basin (part of the Permian)
- The Eagle Ford in South Texas
- The Bakken up in North Dakota
Ryan Lance, the CEO of ConocoPhillips, basically said the goal was to create a "shale powerhouse." By 2025, they were already on track to squeeze out $1 billion in "synergies." That’s corporate-speak for cutting costs and making the combined operations run leaner. If you’re a former Marathon employee or a local contractor, you’ve likely seen the ripples of this already.
Where is the Marathon Oil Houston headquarters now?
This is where it gets kinda confusing for locals. For decades, the "Marathon Oil Tower" at 5555 San Felipe Street was a landmark. It’s that 41-story skyscraper that looks like a giant silver pillar. But Marathon actually moved out of that building in 2021.
They moved to a brand-new, ultra-modern headquarters at 990 Town and Country Blvd in the CityCentre area. It’s a beautiful spot, right off I-10 and Beltway 8.
But here is the kicker: Since the merger closed in late 2024, that office is now part of the broader ConocoPhillips campus network. If you go there looking for the old Marathon logo, you might see it being phased out for the ConocoPhillips "Spirit" logo.
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Don't Get Them Confused with Marathon Petroleum
Seriously, don't.
It is the single most common mistake people make. Marathon Oil (the one in Houston) was an "upstream" company. They focused on finding and drilling for oil. Marathon Petroleum (headquartered in Findlay, Ohio) is a "downstream" company. They focus on refining and gas stations (the ones with the "Speedway" or "Marathon" signs).
While they share a history—they were part of the same company until a spin-off in 2011—they are totally different beasts. If you’re looking for a job at a refinery in Texas City, you’re looking for Marathon Petroleum. If you’re looking for a drilling engineer role in the Eagle Ford, you’re looking at what used to be Marathon Oil.
Why the Houston Presence Still Rocks
Even though the "MRO" ticker symbol is gone from the New York Stock Exchange, the assets haven't moved. The rocks are still there.
Houston remains the nerve center for these operations. The Eagle Ford assets, which Marathon was famous for, are just a short drive south. Marathon was a pioneer in "stack-and-frac" technology—drilling multiple layers of rock from the same spot. ConocoPhillips is now taking those "lessons learned" and applying them to their even larger portfolio.
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The Future of the Assets in 2026
Looking ahead, the integration is basically complete. ConocoPhillips has already started offloading some of the "non-core" assets they inherited. For instance, they signed a deal to sell about $1.3 billion worth of Anadarko Basin assets recently.
They are focusing on the "high-margin" stuff.
For the city of Houston, this means more consolidation. Fewer independent logos on the buildings, but more massive, global-scale operations running out of the West Side.
Actionable Insights for 2026
- For Investors: If you held Marathon Oil stock, your shares have likely been converted to ConocoPhillips (COP) at a ratio of 0.255. Keep an eye on COP's quarterly earnings; they are targeting a $5 billion asset disposition by the end of 2026 to stay lean.
- For Job Seekers: Don't look for a "Marathon Oil" careers page. You need to head straight to the ConocoPhillips portal. They are the ones managing the Permian and Bakken rigs now.
- For Local Vendors: Review your contracts. ConocoPhillips is known for having a very different procurement style than Marathon. They are looking for $1 billion in "run-rate" cost reductions, so they’ll be looking for efficiency.
- Distinguish the Brand: If you see "Marathon Petroleum" (MPC) in the news, remember that's the refining side. They are doing fine on their own, with Maryann Mannen taking over as Chairman and CEO recently.
The story of Marathon Oil in Houston is a classic Texas tale: grow big, get efficient, and eventually become part of something even bigger. It’s not a disappearance; it’s an evolution.
Next Steps:
- Check your brokerage account if you still think you own MRO shares; they have likely been replaced by COP.
- Update your contact lists for the CityCentre office, as many departments have been merged into ConocoPhillips' global operations.
- Monitor the Permian Basin production reports for 2026 to see if the "synergies" promised in the merger actually delivered the promised 2 billion barrels of resource growth.