Partnerships & Construction Industry Scheme

UK partnerships register for the Construction Industry Scheme (CIS)

These forms help UK partnerships register for the Construction Industry Scheme (CIS), report partnership income and allocate profits or losses to individual partners for Self Assessment. CIS304 is used to register a partnership as a construction subcontractor; SA800 reports the partnership’s income and expenses; and SA104F or SA104S reports each partner’s share on their personal tax return. The appropriate form depends on the partnership’s circumstances and the information that must be reported.

CIS304 CIS - Partnership Registration (Subcontractor)

Purpose

The CIS304 is the form that a partnership uses to register as a subcontractor under the Construction Industry Scheme (CIS). Under CIS, contractors deduct tax from payments they make to subcontractors and pass it to HMRC. A partnership that registers receives a lower deduction rate than an unregistered one and can also apply for gross payment status, which means payments are made without any deduction. The form is therefore used both to register for the scheme and, if the partnership qualifies, to apply for.

Deadlines

There is no fixed filing deadline, but the partnership should register before starting work as a subcontractor. Registered subcontractors are generally subject to 20% deductions, while unregistered subcontractors are subject to 30%. Gross payment status is subject to annual compliance checks.

Requirements

Both the partnership and the registering partner must already be registered for Self Assessment and hold a UTR. For gross payment the partnership must pass three tests: a business test, a turnover test and a compliance test. The turnover test requires net construction turnover (excluding VAT and the cost of materials) in the last 12 months of at least £30,000 multiplied by the number of partners, or at least £200,000 for the whole partnership.

Filing Process

Only one partner, the registering partner, completes the form. Page 1 holds the registering partner's details: name, address, Unique Tax Reference (box 3), National Insurance number or, for a corporate partner, the Company Registration Number, and daytime phone, mobile number and e-mail (boxes 1 to 7). Page 2 holds the partnership details: the full partnership name (box 8), partnership address (9), the partnership UTR (10), phone numbers (11 and 12), the date on which work in UK construction started or is planned to start (13), the type of work, for example plumbing, carpentry or electrics (14), any different trading name and trading address (15 and 16), VAT number (17), whether the existing Self Assessment tax adviser may be used (18), whether the partnership has been paid as a subcontractor since 6 April 2007 and the verification number given by the contractor (19), and the chosen tax treatment (20). In box 20 the partnership picks either payment under deduction, in which case it only needs to complete the declaration, or gross payment, in which case it must complete the remainder of the form. For gross payment, page 3 requires details of the other partners, boxes 21 to 26 for partners 2 and 3 (name, address, UTR, NINO or CRN), employer details (boxes 27 and 28, the Accounts Office references), and the business bank account details (29 to 31: account name, sort code and account number). Page 4 contains the turnover test. Enter the maximum number of partners during the last 12 months (box 32), then the gross amount of payments excluding VAT (A), the cost of materials excluding VAT (B), and the net construction turnover (A minus B) in box 33. The registering partner then signs and dates the declaration (boxes 34 and 35) and posts the form to HMRC CIS Contractor Registrations at Benton Park View, Newcastle upon Tyne, NE98 1ZZ. A registering partner without a National Insurance number must call the CIS Helpline on 0300 200 3210.

SA800 Partnership Tax Return 2026 (tax year 6 April 2026 to 5 April 2027)

Purpose

The SA800 is the return that a partnership files to report its trading and investment income and any disposals of chargeable assets for a tax year. A partnership is not taxed itself; the return shows the profit or loss of the partnership as a whole and then divides it between the individual partners in the Partnership Statement, so that each partner can report his or her own share on a personal Self Assessment return (SA104). The return is filed by the nominated partner on behalf of all the partners.

Deadlines

The partnership tax return must reach HMRC by 31 October 2027 if it is a paper return, or by 31 January 2028 if it is filed online. If the notice to file was issued after 31 July 2026, the deadline is three months after the date of the notice, if that is later than the dates above. Each partner who was a member of the partnership during the period is liable to the automatic Partners also need the figures in time for their own personal returns, which are due on the same dates.

Requirements

The nominated partner needs the partnership's UTR, the partnership accounts and the tax computation, with records of sales, expenses, capital asset purchases and sales, bank interest and CIS deductions. It must hold each partner's name, address, UTR and NINO, the profit sharing ratios and the dates on which any partner joined or left, so that the profit can be correctly allocated. Where the partnership accounts do not end between 31 March and 5 April, the profit has to be apportioned to the tax year.

Filing Process

Page 1 is the notice and it should be checked for the tax reference, issue address and filing dates. Page 2 begins with questions Q1 to Q6, which establish which pages are needed: whether the partnership had UK property income (Q1), foreign income (Q2), a trade or profession (Q3), disposals of chargeable assets (Q4), a company, non-UK resident or overseas controlled partner (Q5), whether it is a UKEIG or EEIG (Q6), and whether it exported goods or services (Q6.1). Where the answer is yes, the extra supplementary pages must be obtained and completed. For a trade, fill in the partnership details: business name (3.1), a description of the trade (3.2), start date (3.7), cessation date (3.8), accounting period start and end dates (3.4 and 3.5), and tick box 3.9 if traditional accounting rather than cash basis was used. Page 3 contains the capital allowances summary (boxes 3.13A to 3.23) with the Annual Investment Allowance, writing-down allowances at 18 per cent and 6 per cent, structures and buildings allowances, and the totals in 3.22 and 3.23. If the partnership turnover was below £90,000, the income and expenses summary at boxes 3.24 to 3.26 is used: turnover (box 3.24), expenses allowable for tax (box 3.25) and net profit (box 3.26). Between £90,000 and £15 million the detailed income and expenses page 4 is completed instead, which starts with the sales or turnover figure (3.29), shows cost of sales and other costs, and then lists each expense type (employee costs, premises, repairs, motor, travel, advertising, legal fees, bad debts, interest and so on) with both total expenses and the disallowable portion. It then derives net profit (3.65), the additions for disallowable expenses and balancing charges (3.69), deductions for capital allowances (3.72) and the net business profit for tax purposes (3.73). Page 8 contains Q7 (other income, box 7.9A for untaxed interest), Q8 to Q10 (corrections, phone numbers, adviser, provisional figures, tax avoidance scheme numbers) and Q11, the declaration, which the nominated partner signs and dates in box 11.3.

SA104F Partnership (full) 2026

Purpose

The SA104F is the full Self Assessment page for an individual who is a member of a partnership. It records the partner's share of the partnership's trading profit or loss, untaxed savings income, UK property income, other untaxed UK and foreign income, offshore fund income, dividends and taxed income, and the tax already deducted. It is used when the partnership has income beyond simple trading profits or when the partner has complications such as transition profit, a change of accounting practice or foreign.

Deadlines

The page is filed with the partner's SA100, so the deadline for 2026-27 is 31 October 2027 on paper or 31 January 2028 online. The partnership statement should be provided to each partner as soon as possible after the accounts are prepared so that partners can meet their own deadlines. Tax and Class 4 National Insurance are payable on 31 January 2028, with payments on account where applicable.

Requirements

The partner needs the individual Partnership Statement from the partnership, which shows the share of profits, losses and other income and each box number to be copied, plus the partnership reference number, the dates of joining or leaving, and the accounting period dates to work out the basis period adjustment. Details of earlier losses, CIS statements, foreign tax paid and any untaxed transition profit from 2023-24 are also needed. The partner must also be registered for Self Assessment and have a UTR, and the figures must tie to the partnership's own return (SA800).

Filing Process

At the top, enter the partnership reference number (box 1) and a description of the partnership trade or profession (box 2). Say whether you became a partner after 5 April 2026 and the date (boxes 3Q and 3) and whether you left the partnership after 5 April 2026 but before 6 April 2026 and the date (boxes 4Q and 4). In the trading profits section, enter your share of the partnership profit or loss from box 11 or 12 of the Partnership Statement (box 8), the basis period adjustment (box 9), the change of accounting practice from box 11A (box 10), averaging adjustments (box 11) and foreign tax deducted (box 12). Box 16 gives the adjusted profit for 2026-27. Then enter any transition profit (boxes 16.3 and 16.4), losses brought forward (box 17), taxable profits after losses (box 18), other business income not in the partnership accounts (box 19) and your share of total taxable profits (box 20). If you have a loss, complete boxes 21 to 24, and the National Insurance boxes 25 to 27 follow. The untaxed income pages cover savings (boxes 28 to 35), UK property (boxes 36 to 41.2), other untaxed UK income (boxes 45 to 51), offshore funds (boxes 52 to 55) and other untaxed foreign income (boxes 56 to 63.2). Each section takes the partner's share from the matching box of the Partnership Statement, adds an adjustment for the tax year, deducts brought forward losses and foreign tax, and gives a taxable figure. Page FP 5 totals the untaxed income other than savings (box 67), dividend income (boxes 68 to 70), taxed income at 20 per cent (boxes 71 to 73), other taxed income (boxes 74 and 75) and the share of total taxed and untaxed income (box 76), then records the share of income tax taken off (box 77), CIS deductions (box 78), other tax taken off trading income (box 79) and the total tax taken off in box 80.

SA104S Partnership (short) 2026

Purpose

The SA104S is the shorter version of the partnership page of the Self Assessment return. A partner uses it when the share of the partnership's income is simple, essentially a share of trading or professional profit or loss, with some untaxed interest and tax deductions, and there are no extra items such as untaxed foreign income, property income in the partnership or untaxed transition profit. It gets the partner's share of the profit from the Partnership Statement onto the personal tax return.

Deadlines

The deadlines are those of the SA100: 31 October 2027 for a paper return and 31 January 2028 for an online return for 2026-27. The balancing payment of tax and Class 4 National Insurance falls due on 31 January 2028, with the second payment on account on 31 July 2028.

Requirements

The partner needs his or her copy of the Partnership Statement (short) for the year, which is produced by the partnership from its own SA800. The partner also needs the partnership reference number, the dates of joining or leaving, records of earlier losses, and details of any CIS deductions. If the partner has untaxed transition profit, foreign income or other complicating items, the SA104F must be used instead of the short page.

Filing Process

Enter your name and UTR at the top, then the partnership reference number (box 1) and a description of the trade (box 2). Say whether you became a partner after 5 April 2026 and the date (3Q and 3), and whether you left the partnership during the year and the date (4Q and 4). In the profits section, enter your share of the partnership's profit or loss (box 8) from box 11 or box 12 of the Partnership Statement, the adjustment for an accounting period that ended before 31 March 2026 or was not 12 months long (box 9), the adjustment for change of accounting practice from box 11A (box 10), any averaging adjustment (box 11) and foreign tax deducted (box 12). Add these to arrive at the adjusted profit for 2026-27 in box 16, deduct losses brought forward (box 17) to give taxable profits in box 18, add other business income not in the partnership accounts (box 19) and arrive at your share of total taxable profits in box 20. If the partnership made a loss, enter the adjusted loss (box 21), the loss set off against other income (box 22), the loss carried back (box 23) and the total loss carried forward (box 24). Boxes 25 to 27 deal with Class 2 and Class 4 National Insurance: a tick to pay voluntary Class 2, a tick if exempt from Class 4, and any adjustment to Class 4 profits. Box 28 is your share of untaxed interest from box 13 of the Partnership Statement, box 30 is your share of CIS deductions from box 24 and box 31 is your share of other tax taken off trading income from box 24A. Any other information goes in box 32.