Beyond claiming the reliefs a company is entitled to, the remaining levers are about timing and structure rather than about entitlement. They are smaller than the reliefs and they are entirely legitimate, and they share one property: they only work if the decision is taken before the year end rather than discovered after it.
Timing, which is the real lever
A cost deductible in this period reduces this period's tax; the same cost a fortnight later reduces next period's. That matters most when the company is near a threshold, because the effective rate in the marginal relief band is higher than the main rate on the top slice of profit. Bringing forward an employer pension contribution, a bonus that will be paid within nine months, or a piece of equipment purchase can therefore be worth more than the same decision in a year when profit sits comfortably in one band.
The associated companies count
This is structural and it is the one most often wrong. The £50,000 and £250,000 thresholds are divided by the number of associated companies, so a founder holding three companies reaches the main rate at a quarter of the profit. Dormant companies and companies not carrying on a business are excluded from the count, which means a genuinely dormant holding company should not be dragging the thresholds down and sometimes is, because nobody checked.
Extraction, and what it does not do
Salary and employer pension contributions are deductible and reduce the company's profit; dividends are not and do not. That is often described as a way to reduce corporation tax and it is really a decision about the total tax on the money across both taxpayers, because salary attracts national insurance where a dividend does not. The honest framing is that extraction changes who pays and how much in total, not that it reduces the company's tax for free.
Questions people ask about ways to reduce corporation tax
Does paying myself a salary reduce corporation tax?
Salary and employer pension contributions are deductible and reduce company profit; dividends are not. But salary carries national insurance, so the real question is the total tax across the company and the director.
Does buying equipment before the year end help?
It can, if the expenditure is incurred in the period and qualifies. It matters most when profit is near a threshold, because the effective rate in the marginal relief band is higher than the main rate.
Can I reduce the number of associated companies?
Dormant companies and companies not carrying on a business are already excluded from the count. Whether an entity is genuinely dormant is a question of fact, not a choice.