NS&I Index-Linked Savings Certificates: A Guide for Legacy Holders 2026
NS&I stopped selling new Index-Linked Savings Certificates years ago, but existing holders can still renew maturing certificates into a new term. Here is what legacy holders need to know in 2026.
A closed product that still matters to existing holders
Index-Linked Savings Certificates are one of NS&I's best-known historic products, valued for combining complete capital security with inflation-linked, entirely tax-free returns. They are no longer available for new general sale, but a meaningful number of savers still hold certificates from years when they were on general sale, and many are periodically eligible to renew at maturity.
Savings Calculator
Project how your savings will grow over time with regular deposits and interest.
Open Savings calculatorHow the tax-free status works
| Feature | Index-Linked Savings Certificate | Typical taxable savings account |
|---|---|---|
| Index-linked capital uplift | Tax-free | N/A (not typically index-linked) |
| Interest/fixed additional rate | Tax-free, no PSA limit | Taxable above Personal Savings Allowance |
| Capital Gains Tax | Not applicable — no CGT event | Not applicable to cash savings either |
| FSCS-style protection | 100% government-backed (NS&I, no cap) | £85,000 per institution (FSCS) |
Worked example 1: certificate reaching maturity
Grace holds a certificate that matures in 2026. NS&I writes to her with her options.
| Option | What it means |
|---|---|
| Renew into a new term (if currently offered to existing holders) | Capital continues to be index-linked, still tax-free |
| Transfer proceeds to another NS&I product | Moves to whatever NS&I products are currently open |
| Withdraw in full | Money paid out, certificate closed |
Grace should read her specific maturity letter carefully, since the exact renewal terms and rates on offer at any given point can differ from what was available when she originally took out the certificate.
Worked example 2: comparing a legacy certificate against a Cash ISA today
Hassan is deciding where to put new savings today (he does not hold an existing Index-Linked Savings Certificate to renew).
| Option | Available to Hassan? |
|---|---|
| New Index-Linked Savings Certificate | No — not on general sale |
| Cash ISA | Yes — up to £20,000/year, tax-free |
| Other currently-open NS&I products (e.g. Premium Bonds, Direct Saver) | Yes, subject to their own specific terms |
Since Hassan cannot buy a new certificate, his realistic tax-free comparison today is a Cash ISA or another currently-open product, not the legacy certificate itself.
Worked example 3: tracking down an old, forgotten certificate
Priya finds an old paper certificate belonging to a late relative among some family paperwork, with no clear record of its current value.
| Step | Action |
|---|---|
| Contact NS&I | Provide certificate number/reference details found on the paperwork |
| Confirm status | NS&I confirms current value and whether it is still active or matured awaiting claim |
| Claim proceeds | Unclaimed NS&I savings never expire and remain payable |
Inflation Calculator
Find out what a sum of money from the past is worth in today's money, or how much prices have risen over time using UK CPI data.
Open Inflation calculatorThe bottom line for legacy holders
If you already hold an Index-Linked Savings Certificate, check your maturity letter carefully for the exact renewal, transfer, or withdrawal options currently on offer — these change over time. If you do not hold one and are looking for a comparable tax-free, inflation-aware savings option today, a Cash ISA or another currently-open NS&I product is the realistic starting point, since new Index-Linked Savings Certificates are simply not available to purchase from scratch.
Use the savings calculator and inflation calculator to compare the real, inflation-adjusted return on any savings option you are currently considering.
Frequently asked questions
Can I still buy new Index-Linked Savings Certificates in 2026?
No — NS&I withdrew Index-Linked Savings Certificates from sale to new customers some years ago and has not reopened general sales since. If you do not already hold one, you cannot buy a brand new certificate directly, though existing holders have historically been able to renew a maturing certificate into a new term, subject to whatever terms NS&I is currently offering to existing holders.
Are Index-Linked Savings Certificates tax-free?
Yes — this has always been their key feature. Both the index-linked capital uplift and any fixed additional interest earned are entirely free of UK Income Tax and Capital Gains Tax, regardless of your tax band, unlike most other savings products, which are subject to your Personal Savings Allowance and further tax above it.
How is the index-linking actually calculated?
Certificates issued over the years have been linked to either the Retail Prices Index (RPI) or, in some cases, the Consumer Prices Index (CPI), depending on when the specific certificate was issued. The capital value of your certificate is uprated in line with the relevant index over your holding period, plus a small additional fixed rate of interest specified at the time you took out (or renewed) that particular certificate.
What happens when my certificate matures?
At maturity, NS&I typically writes to you with your options, which have historically included: renewing into a new certificate term (if NS&I is accepting renewals for existing holders at that time), transferring the proceeds to another NS&I product, or withdrawing the money entirely. Options available change over time as NS&I's product range evolves, so always check the specific current options offered in your maturity letter rather than assuming past terms still apply.
Is my money safe if I hold Index-Linked Savings Certificates?
Yes — NS&I products are backed by HM Treasury, meaning 100% of your money is protected regardless of the amount, unlike the £85,000 Financial Services Compensation Scheme limit that applies to bank and building society deposits. This is one of the reasons these certificates have historically been popular with savers wanting complete capital security alongside inflation protection.
Should I cash in my certificate now or wait for maturity?
This depends on your personal circumstances, current inflation expectations, and what alternative savings or investment options are available to you at competitive rates. Cashing in early can sometimes reduce the return compared with holding to the full maturity date, depending on the specific certificate's terms, so check your certificate's exact early-encashment rules before deciding, and compare against current best-buy tax-free alternatives like a Cash ISA.
How do Index-Linked Savings Certificates compare with a Cash ISA now?
Both are tax-free, but a Cash ISA is generally accessible to any UK adult today, with a £20,000 annual subscription limit, while Index-Linked Savings Certificates are only available to those who already hold one and are renewing — you cannot start fresh with this specific product. If you are choosing where to hold new tax-free savings today, a Cash ISA (or other currently-open NS&I product) is the relevant comparison, not a legacy certificate you cannot newly purchase.
Does holding an Index-Linked Savings Certificate affect my Cash ISA allowance?
No — Index-Linked Savings Certificates are a completely separate NS&I product from the ISA system, and holding or renewing one has no effect on your annual £20,000 ISA subscription allowance, since it does not use any part of your ISA wrapper.
What should I do with an old certificate I'd forgotten about?
Contact NS&I directly (via their website or customer service) with any reference details you have (certificate number, your NS&I customer number if known) to check its current value and status. Unclaimed NS&I savings, including old certificates, do not expire and remain payable indefinitely, so it is always worth tracking down and claiming forgotten holdings rather than assuming they are lost.
Try the calculators
Related reading
Catching Up Pension Contributions After a Career Break: 2026/27 Guide
How to catch up on pension contributions missed during a career break, using pension carry forward, non-worker contributions, and National Insurance credits.
Transferring a Final Salary Pension: The Mandatory Advice Rule in 2026/27
Why UK law requires regulated financial advice before transferring a final salary (defined benefit) pension worth over £30,000, and what the transfer value comparator and tax implications mean in 2026/27.
Flexible Retirement: Working Part-Time While Drawing Your Pension in 2026/27
Reducing hours while starting to draw a pension changes your tax code, may trigger the Money Purchase Annual Allowance, and can affect Marriage Allowance eligibility. How flexible retirement works in 2026/27.