Guidance: Preston Guidance: January 2026

Why It Matters

Employers must adopt the new Preston factors to comply with court‑mandated pension reinstatement, affecting cost structures and employee retention. Accurate application ensures fair treatment of part‑time staff and avoids regulatory penalties.

Key Takeaways

• Preston earnings and interest factors released for January 2026
• Guidance supports part‑timer pension reinstatement after EU/UK rulings
• Employers must use factors to calculate actuarially fair costs
• Excel annexes provide detailed tables for pension calculations
• Accessible format available upon request for disabled users

Pulse Analysis

The 2000‑2001 rulings by the European Court of Justice and the UK House of Lords created a legal precedent that part‑time employees are entitled to retroactive access to occupational pension schemes, provided they meet specific criteria. This decision introduced the concept of actuarial fairness, where reinstated members should neither gain nor lose value compared with continuous contributions. To operationalise this principle, the Treasury developed the Preston factors – standardized earnings and interest rates that translate legal rights into quantifiable pension values.

The latest guidance, issued on 2 March 2026, delivers the January 2026 Preston factors in two downloadable Excel files: the Preston Model Annex and the Employee NICs Rebate spreadsheet. These tools enable payroll and benefits teams to compute the precise pension service credit and associated National Insurance contributions for eligible part‑timers. By integrating the factors into existing pension administration systems, employers can ensure that reinstatement costs are actuarially neutral, preserving the financial integrity of their schemes while remaining compliant with statutory obligations. The Treasury also offers accessible versions of the files on request, underscoring a commitment to inclusive data provision.

For businesses, the rollout of these factors carries immediate operational and strategic implications. Accurate calculations affect cash‑flow forecasts, pension funding ratios, and employee retention strategies, especially in sectors with high part‑time workforces. Failure to apply the correct factors could trigger regulatory scrutiny or costly remedial actions. Looking ahead, the Treasury signals that future updates will align with evolving case law and economic conditions, making ongoing monitoring essential for HR and finance leaders seeking to maintain equitable, compliant pension practices.