The Autumn Budget Aftermath: Why the 2025 NI Hike Changes Your Entire Reward Strategy

The Chancellor's Autumn Budget confirmed what many finance teams feared: employer National Insurance will rise to 15% from April 2025, while the secondary threshold drops from £9,100 to £5,000. That combination increases the NI liability on every eligible employee. For a business with 100 staff, the change is material. For a business growing its headcount through 2025, it compounds. This piece analyses what the change means for your total employment cost — and which elements of your reward strategy can be restructured to offset it.

What the Budget Actually Announced — and What the Numbers Mean

The October 2024 Autumn Budget delivered two simultaneous changes to employer National Insurance. First, the rate increased from 13.8% to 15%. Second, the secondary threshold — the salary level above which employer NI becomes payable — dropped from £9,100 to £5,000 per year. The Employment Allowance increased to £10,500 (with the £100,000 eligibility cap removed), offering some relief for smaller employers. But for businesses above that allowance threshold, or those with payrolls that outstrip it, the net effect is a higher employer cost per head.

To understand the practical impact, consider an employee earning £35,000. Under the previous regime, employer NI applied to £25,900 (£35,000 minus the £9,100 threshold) at 13.8%, giving a liability of approximately £3,574. Under the new regime, the same employee generates an NI liability on £30,000 (£35,000 minus the new £5,000 threshold) at 15% — approximately £4,500. That is an increase of around £926 per employee per year, before accounting for any other payroll changes. Across a team of 100, that figure becomes significant.

Why Your Current Benefits Stack May No Longer Be Cost-Neutral

For most employers, the benefits review that followed the Budget will have focused on cost control. That is the right instinct, but it misses a structural opportunity. Employee benefits are not simply a wellbeing overhead — they are one of the few mechanisms through which employers can legitimately reduce the NI they pay without reducing headcount or salary.

Many businesses are currently running benefits programmes that generate no NI saving for the employer. Perks funded from post-tax salary, voucher schemes, or discretionary allowances do not reduce the gross salary bill. That means they carry no offset against NI liability. In the context of a 15% rate and a lower threshold, that is an increasingly expensive position to hold.

The question for Finance and HR teams going into 2025 is not whether to offer benefits, but which benefits structure actually reduces the payroll cost line.

The Case for Repositioning Benefits as a P&L Tool, Not a Perk Catalogue

Salary sacrifice arrangements reduce an employee's gross salary in exchange for a non-cash benefit provided by the employer. Because the employee's gross salary is lower, both employer and employee NI are calculated on a smaller figure. That reduction in employer NI is a direct saving — not a rebate, not an assumption, but a change to the calculation.

This is not a new mechanism. But its commercial significance increases in direct proportion to the employer NI rate. At 13.8%, a salary sacrifice arrangement saving £5,000 of gross salary per employee reduced the employer NI bill by £690 per person per year. At 15%, the same arrangement saves £750. The higher the rate, the more valuable the offset.

For Finance Directors reviewing the 2025/26 employment cost forecast, salary sacrifice arrangements — particularly those covering electric vehicles and technology — merit inclusion in the cost modelling, not just the benefits catalogue.

Which Salary Sacrifice Schemes Directly Reduce Employer NI Liability

Not all benefits generate an NI saving for the employer. The mechanism only applies where the arrangement is structured as a genuine salary sacrifice — the employee contractually gives up gross salary in exchange for the benefit.

Schemes that qualify under current HMRC rules include:

• Electric vehicle (EV) salary sacrifice — a low Benefit-in-Kind (BIK) rate makes this the most commercially efficient option available in 2025. At 3% BIK for the 2025/26 tax year, the employer and employee NI savings significantly outweigh the BIK liability for most employees.

• Technology and mobile phone schemes — employees sacrifice gross salary to receive devices provided by the employer, with no BIK charge for mobile phones in many cases.

• Workplace nursery schemes — where the employer has financial and management responsibility for the provision, the exemption removes both income tax and NI on the benefit's value.

• Pension contributions via salary sacrifice — reduces gross salary and therefore employer NI, in addition to the pension tax relief already available.

• Cycle to work schemes — a modest but straightforward NI saving with no BIK charge.

What Finance Teams Should Be Modelling Before April

The window between the Budget announcement and the April 2025 implementation date is the planning window. Finance teams that use it well will enter the new tax year with a quantified offset strategy. Those that do not will absorb the full cost increase.

The modelling exercise is straightforward. For each salary sacrifice scheme under consideration, the inputs are: headcount eligible for the scheme, average salary sacrifice amount per participant, current and projected employer NI rate, and estimated take-up rate. The output is a projected annual NI saving that can be set against the cost of scheme administration.

For most mid-market employers running EV or technology schemes with meaningful participation rates, the administration cost is materially outweighed by the NI saving. The question is not whether the numbers work — it is whether the scheme is communicated well enough to achieve the take-up rate the model assumes. That communication challenge is explored in our guide to communicating salary sacrifice to sceptical employees.