Where Group I base oils remain essential: marine, industrial, and price-sensitive markets

Much of the trade press frames the base oil market as a one-way migration from Group I toward Group II and Group III, as if Group I were a legacy product on its way out. The data tells a more accurate story: Group I remains the single largest product segment in the global base oil market by revenue, holding over 41% of the market in 2025 — more than Group II and Group III combined. In several application categories, it isn't losing ground at all.

Marine lubricants: mineral oil's stronghold

Marine lubricants are one of the fastest-growing segments of the entire lubricants industry, with the global market valued at roughly $9.4 billion in 2025 and projected to grow at an 11% annual rate through 2030 — driven directly by the same growth in seaborne trade and commercial shipping fleets that underpins bulk commodity corridors like the ones bitumen and base oil themselves move through. Within that market, mineral oil — the Group I-based category — holds a commanding 74.5% share of global marine lubricant formulations, with bulk carriers and tankers as the largest consuming vessel types. This is not a segment where Group III synthetics have displaced the incumbent; it's one where Group I-derived mineral base oils remain the default choice for engine oils, hydraulic fluids, and gear oils across most of the world's commercial fleet.

Bright Stock: the heavy-duty grade that keeps getting tighter, not weaker

Within Group I, Bright Stock — the high-viscosity fraction used in marine oils, gear lubricants, greases, and heavy-duty industrial applications — has shown some of the clearest signs of continued strategic importance. Rather than showing signs of demand erosion, Bright Stock has recently been at the center of a genuine supply squeeze: base oil prices, including Bright Stock, SN500, and SN150 grades, surged by as much as 165% within roughly ten weeks in early 2026, driven by reduced Asian refinery run rates, crude price volatility, and buyers rushing to secure cargoes ahead of expected further shortages.

My own read on this is that it looks less like a permanent restructuring of the market and more like a cyclical squeeze tied to this year's specific supply and demand conditions — refiners cutting run rates at the same time buyers panicked into pre-buying. Those two forces don't usually persist together indefinitely. But even a temporary squeeze is a useful signal: it shows Group I and Bright Stock still have real pricing power when supply tightens, which isn't what you'd expect from a genuinely obsolete product line. Industry analysts don't expect Group II/III supply economics to fully normalize until at least mid-2027 — meaning Group I grades, Bright Stock especially, are likely to stay commercially relevant, and closely watched, for some time yet.

Process oils and industrial applications: a quietly growing category

Beyond automotive and marine use, process oils used in rubber, plastics, and specialty chemical manufacturing represent one of the base oil market's faster-growing application segments, expanding at a projected 7.1% annual rate. These formulations rely heavily on the specific solvency and compatibility characteristics of Group I stocks, which is why rubber processors and industrial oil blenders have not followed the same migration path as passenger-vehicle engine oil formulators.

Price-sensitive markets: where established supply chains still win

In markets like South Asia and parts of Africa — many of the same corridors covered in our previous piece on bitumen demand — Group I's established supply chains, wide availability, and compatibility with existing blending infrastructure keep it the practical default for a large share of blenders. Group III's technical advantages matter most where regulation specifically requires them (as with tightening vehicle emissions standards); where that regulatory pressure is lighter or absent, cost-effectiveness and supply reliability continue to favor Group I formulations.

What this means for buyers and suppliers

The honest picture is not “Group I versus Group II/III” as a race with a predetermined winner — it's a market segmenting by application. Marine operators, industrial rubber and grease manufacturers, and price-sensitive blenders across South Asia and Africa are not migrating away from Group I; if anything, current supply tightness suggests the opposite pressure. For a broker working in this space, that means Group I sourcing relationships remain a genuinely strategic asset — not a hedge against an inevitable decline, but a position in a market segment with real, durable demand of its own.

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