UK SIC 2007 · 09100
Support activities for petroleum and natural gas mining (SIC code 09100)
Support activities for petroleum and natural gas mining is UK SIC code 09100. It sits in division 09 (Mining support service activities) of the SIC 2007 list. On the August 2026 Companies House register, 3,093 active UK companies list 09100 among their SIC codes. 2,927 of them list it first. That makes it the most used code in its division.
Division 09: Mining support service activities
Companies here service extraction sites. They do not extract anything themselves. One code dominates in the UK: 09100, support activities for petroleum and natural gas. It covers directional drilling, well casing and cementing, derrick erection and other oilfield services. A large share of these companies are one-person vehicles. Engineers and consultants set them up to contract into North Sea operators. The rest are real service firms with their own crews and equipment.
Related SIC codes
Who prospects SIC 09100 companies
Energy recruiters read this division as a live map of the contractor market. A new incorporation usually means an engineer has just gone independent. That person will need placements. Contractor accountants, IR35 specialists and offshore insurers chase the same moment. Growth signals matter more for the bigger service firms. As headcount rises they buy recruitment, certification and logistics support. Work here comes in project cycles. Recent accounts and confirmation statements tell you who is still active, and who is a leftover shell from an old contract.
Lead generation for recruiters →How to read SIC 09100
SIC 09100 is a five-digit code, and the digits are not arbitrary. The first two, 09, are the division, mining support service activities. Add the third and you have group 091; the fourth narrows it to a class, and the fifth to the subclass, which is the level Companies House actually asks a company to pick. The whole division sits under section B, mining and quarrying, the broadest tier there is. Reading a code left to right therefore goes from a whole sector down to one activity.
More on how SIC 09100 is built
A company chooses its own codes when it incorporates and can change them on any confirmation statement. It may list up to four, and Companies House does not check whether they are right. That is why 09100 is worth reading as a claim the company made about itself rather than as a verified fact, and why the first-position and any-position counts above differ.
Measured on the August 2026 register, the busiest registered-office post towns for 09100 are London (509), Aberdeen (349), Montrose (113), Glasgow (63) and Great Yarmouth (57). Those are registered-office locations, which is where the paperwork sits rather than necessarily where the work happens, so treat them as where to start looking rather than as a service area.
Using SIC 09100 as a filter
3,093 companies is 0.06 per cent of the 5,190,464 active companies on the UK register, and ranks 09100 most used of the 2 codes we track in division 09. That is the pool before any filter. Whether it is a big market for you depends on what you sell, but it is the number every other filter on this page cuts down from.
More on filtering by SIC 09100
Almost everybody who uses 09100 means it: 2,927 of 3,093 companies put it first, leaving only 166 carrying it as a secondary code. That makes it an unusually clean filter. You can match on the code alone and trust that the companies you get really are in this line of work.
The population is concentrated: the five busiest post towns hold 35 per cent of it, and London alone accounts for 16 per cent. If you sell nationally, those five towns are most of the market. If you sell locally and you are not in one of them, expect a much smaller pool and widen the radius early.
In practice the code on its own is rarely the whole filter. Pair 09100 with an incorporation date to catch companies in their first months, when they are still choosing suppliers, or with a filing deadline to reach them while the year end is on their mind. A worked example for this code: 09100, registered office in London, incorporated in the last ninety days, which turns a 3,093 company pool into a list you can write to in an afternoon. Add the poor-website filter if what you sell is a website, or a recent change of officer if you sell to whoever just took the job. Every company you pull carries the Companies House record, the director's name, a verified website and a verified email, and the ones we cannot complete are not charged.
SIC 09100 companies, as leads
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About SIC 09100
How many UK companies use SIC code 09100?
3,093 active UK companies list 09100 (Support activities for petroleum and natural gas mining) among their registered SIC codes. Each company may register up to four. Of those, 2,927 put it first. The figures come from the August 2026 Companies House register snapshot, and count active companies only.
Which SIC code should an oil and gas contractor's limited company use?
Use 09100 if your work directly supports drilling or well operations. Most offshore contractors pick it. Engineers doing design or consultancy sometimes use an engineering code from division 71 instead. Both are fine. You declare your own code at incorporation and nobody at Companies House judges the fit. Agencies and insurers may still expect something that suits the sector.
My contract has ended. Should I change my company's SIC code or make it dormant?
You do not need to change the code between contracts. If the company stops trading altogether, you can file dormant accounts. Some owners switch the code to 99999 to show that. You update a code on your next confirmation statement, and it takes effect once filed. You can switch it back just as easily when new work starts.
Find UK SIC 09100 companies
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