Base Oil Supply — Group I SN 150/500/650, Group II, Group III, PAO

Base oils are the refined mineral or synthetic stocks that make up 70 to 99 % of a finished lubricant. We supply Group I SN-series oils, Group II, Group III and Group IV (PAO) base stocks to blenders, distributors and industrial users.

Every grade is sold against a contract specification confirmed by independent inspection at loading. The parameters that matter for a base oil are:

Quality parameters

Kinematic viscosity at 40 °C and 100 °C
Viscosity index (VI)
Flash point and pour point
Colour (ASTM D1500) and appearance
Sulphur and saturates content
Noack volatility, for Group III and PAO
Cold-cranking viscosity, for engine-oil grades
Water content, acid number and ash

Classification

How base oils are grouped

The American Petroleum Institute sorts base stocks into five groups by saturates, sulphur and viscosity index. Moving from Group I to Group III raises purity and viscosity index — and the price.

API 1509 base oil groups
Group	Typical process	Saturates	Sulphur	Viscosity index	Common grades
Group I	Solvent refining	< 90 %	> 0.03 %	80 – 119	SN 70, SN 150, SN 500, SN 650, Bright Stock 150
Group II	Hydrocracking and hydrofinishing	≥ 90 %	≤ 0.03 %	80 – 119	N 70 / 60N, N 150, N 500, N 600
Group III	Severe hydrocracking, catalytic dewaxing or gas-to-liquids	≥ 90 %	≤ 0.03 %	≥ 120	4 cSt, 6 cSt, 8 cSt (Group III+ at VI ≥ 130)
Group IV	Synthesis (oligomerisation of alpha-olefins)	—	—	about 125 – 170	PAO 4, 6, 8, 10; mPAO 40, 100
Group V	All other base stocks	—	—	—	Esters, naphthenics, polyalkylene glycols

Grades

From SN 150 to PAO 100

Solvent-neutral (SN) grades are named after their Saybolt viscosity at 100 °F; Group II and III grades after their viscosity at 100 °C. The values below are typical of the market, not a specification: the contract specification and the certificate of analysis prevail.

Base oil grades we supply — typical values
Grade	KV at 100 °C, cSt	Viscosity index	Flash / pour point, °C	Typical use
SN 150 (Group I)	4.9 – 5.6	≥ 95	≥ 200 / ≤ −9	Light engine and hydraulic oils, metalworking fluids
SN 500 (Group I)	10.3 – 11.5	≥ 95	≥ 230 / ≤ −6	Monograde and HD engine oils, gear and industrial oils
SN 650 (Group I)	13 – 15	≥ 95	≥ 240 / ≤ −6	Heavy engine and gear oils, greases
Bright Stock 150 (Group I)	30 – 33	≥ 95	≥ 280 / ≤ −3	Marine cylinder oils, heavy gear oils, greases
N 150 (Group II)	5.0 – 5.5	100 – 110	≥ 210 / ≤ −12	Passenger-car and HD engine oils, hydraulic oils
N 500 / N 600 (Group II)	10.5 – 12.5	95 – 105	≥ 240 / ≤ −9	HD engine oils, industrial gear oils
4 cSt (Group III)	4.0 – 4.5	≥ 120	≥ 215 / ≤ −15	0W and 5W engine oils, ATF
6 cSt (Group III)	5.8 – 6.5	≥ 120	≥ 230 / ≤ −12	5W-30 and 5W-40 engine oils
8 cSt (Group III)	7.5 – 8.5	≥ 120	≥ 240 / ≤ −9	10W-40 and 15W-40 engine oils, industrial oils
PAO 4 / 6 / 8 (Group IV)	4 / 6 / 8	125 – 140	≥ 220 / ≤ −55	Full-synthetic engine oils, compressor and hydraulic fluids
mPAO 40 / 100 (Group IV)	40 / 100	150 – 170	≥ 270 / ≤ −35	Industrial gear oils, greases, viscosity building

KV = kinematic viscosity. Group I values follow common Asian and Middle East refinery specifications; Group II, III and PAO values follow the producers’ typical data sheets.

Quality

What the groups mean in practice

Group I — solvent refined

The traditional base stock, with natural solvency that suits monograde engine oils, industrial oils, process oils and greases. Capacity is shrinking as old plants close, which keeps Bright Stock and SN 650 tight.

Group II and III — hydroprocessed

Hydrocracking removes sulphur and aromatics, giving better oxidation stability and lower volatility. Group II is now the mainstream engine-oil stock; Group III is what makes most “synthetic” engine oils.

Group IV — PAO

Polyalphaolefins are built from ethylene rather than refined from crude. They have the widest temperature range — pour points below −50 °C — and are used where Group III is not enough, blended with esters for additive solubility.

Market prices

How base oils are priced

Base oils are priced per tonne, FOB or CFR, against the weekly assessments of price-reporting agencies for each region. The main markers are:

Asia — FOB Asia and ex-tank Singapore for Group I and II; FOB Asia and CFR India for Group III; CFR China for imported Group II and III
Europe — FOB Rotterdam and ex-tank Northwest Europe; FOB Mediterranean for Group I
Middle East — FOB Middle East Gulf for Group II and III from the Gulf’s large hydrocracker plants
United States — producers’ posted prices and FOB US Gulf export prices

Prices follow crude and the gasoil crack with a lag of a few weeks, move with the spring blending season, and react to plant turnarounds and to the steady closure of Group I capacity. A premium for Group III over Group II and for Group II over Group I is normal; the spread between them is what a trader watches.

Brent crude — live price

Market data: TradingView. Indicative and possibly delayed; not for trading.

Crude sets the cost of the vacuum gas oil that base oil plants run on. All live markets

Gasoil — live price

Market data: TradingView. Indicative and possibly delayed; not for trading.

Base oils compete with gasoil for the same refinery streams; the gasoil crack is the first thing a base oil trader checks. All live markets

Base oil, additive and catalyst prices are assessed by price-reporting agencies and by producers’ postings. Those assessments are licensed and are not reproduced here. We send written price indications on request, indexed to the published assessment of the buyer’s choice.

We do not publish price lists or “available allocations”. Offers are issued in writing only, from an @alupetra.com address, once KYC is complete for both parties.

Questions

Frequently asked questions

What is the difference between Group I, Group II and Group III base oil?

The API grouping. Group I is solvent refined, with less than 90 % saturates or more than 0.03 % sulphur. Group II is hydroprocessed, with at least 90 % saturates and no more than 0.03 % sulphur, and a viscosity index of 80 to 119. Group III meets the same purity but has a viscosity index of 120 or more, which allows low-viscosity engine oils with low volatility.

Why is a Group I grade called SN 500?

SN stands for solvent neutral. The number is the oil’s approximate Saybolt Universal viscosity at 100 °F — about 500 SUS, which is roughly 95 to 105 cSt at 40 °C and 10.5 to 11.5 cSt at 100 °C. SN 150 and SN 650 follow the same convention; Bright Stock 150 is named after its viscosity at 210 °F.

Where can I find base oil prices?

Base oils are not traded on an exchange. Weekly assessments are published by price-reporting agencies such as Argus, ICIS and S&P Global Commodity Insights under licence, and the large US producers post their domestic prices. We cannot reproduce those assessments here; we quote in writing against the assessment the buyer chooses, and this page shows the live crude and gasoil prices that drive them.

Can Group III replace PAO?

For most passenger-car engine oils, yes — Group III and Group III+ stocks meet current low-viscosity specifications at a lower cost. PAO remains necessary where very low pour points, very high viscosity index or long drain intervals are required, for example in Arctic, aviation, compressor and some industrial gear applications.

Which documents accompany a base oil cargo?

A bill of lading or CMR, the producer’s certificate of analysis, a certificate of origin, the independent inspector’s quantity and quality report and, for packed goods, the packing list. A safety data sheet is supplied for each grade.

Products