Keep a closed Help to Buy ISA if you will complete a qualifying home purchase within two years. Premium Bonds suit savers who accept prize volatility and want instant access instead of a guaranteed 25% bonus.
Key factors to decide
Compare the HTB one-off bonus value to the expected annual return from Premium Bonds and the time until you need the money. The HTB bonus is a single guaranteed uplift at completion for qualifying purchases. Premium Bonds give tax-free prizes but no guaranteed yield.
What the HTB bonus is
The HTB bonus equals 25% on eligible savings up to a £3,000 maximum. The scheme opened in December 2015 and closed to new accounts in November 2019. The wider legal framework includes the Financial Services and Markets Act 2000.
When the bonus matters most
If the HTB bonus significantly increases a deposit within one to two years, preserve it. The most frequent error at this point is withdrawing funds or moving money incorrectly. That action can void the bonus and cost thousands.
Keep paperwork copies in one safe folder for quick access.
How to compare value quickly
Calculate the HTB uplift as Balance times 25%. Compare that uplift to Premium Bonds expected value, Balance times the prize-fund rate.
Try scenarios for prize-fund rates of 0.5%, 1.0% and 2.0%. Work out how many years of expected prizes equal the HTB bonus.
For example, the HTB bonus on £12,000 is £3,000. This one payment often beats several years of expected Premium Bonds returns for typical prize rates.
Using a help to buy ISA for your deposit: what to do
If the HTB funds will go into a qualifying home purchase, do not withdraw them. Tell your solicitor or conveyancer immediately so they can claim the bonus at completion. The solicitor submits the HTB claim pack at completion and receives the bonus into the completion monies.
Tell the solicitor early
Tell the solicitor as soon as you exchange contracts or even earlier when making an offer. The solicitor needs the HTB paperwork to claim the bonus at completion. Provide the account details and any written confirmation from the ISA provider.
If you do not need the bonus
If the bonus is not needed, use an official ISA transfer instead. Ask the receiving provider to request the transfer in writing. The receiving provider must initiate the transfer so the HTB wrapper stays intact until claim.
Keep paperwork copies in one safe folder for quick access.
What the solicitor will need
The solicitor will need a written letter from the ISA provider confirming the HTB balance and account status. The solicitor also needs the specific Help to Buy ISA claim form or HTB checklist. Ask the provider for the exact name of the form to avoid delays.
Timings and transfers
Start transfers or preservation steps six to eight weeks before exchange of contracts. Internal transfers typically take five to ten working days. Inter-bank transfers usually take ten to thirty working days.
Protecting the bonus and creating evidence
Obtain written confirmation from the ISA provider that they will support the HTB claim at completion. Email the ISA provider and ask them to send the HTB claim form to your solicitor. Keep all emails and references in the conveyancing file as verifiable evidence.
Premium bonds mechanics and whether a cash ISA is better
Premium Bonds, backed by National Savings and Investments, pay tax-free prizes but no guaranteed interest. Use expected-value maths and probability to compare them with guaranteed returns such as a Cash ISA or the HTB one-off bonus.
Expected annual return equals Balance times the prize-fund rate, R. The probability of at least one win equals one minus the probability of no wins. Check NS&I for the current per-bond per-draw chance p.
Odds and small balances
If NS&I states roughly one in 24,000 chance per £1 bond per draw, holding 5,000 £1 bonds gives a low monthly win chance. For balances under about £6,000 the chance of no prize in a year can be substantial. Many savers underestimate the risk of long dry spells.
Keep paperwork copies in one safe folder for quick access.
How to estimate break-even years
Years to match a one-off bonus = HTB bonus ÷ (Balance × R). Example: Balance £5,000 gives HTB bonus £1,250. At R = 1% the expected value per year is £50. Years equals 1,250 divided by 50, which is 25 years.
When a cash ISA is usually better
For a two to five year goal that needs predictable growth, a competitive Cash ISA often beats Premium Bonds when prize rates are low. A Cash ISA gives steadier returns and compounding, which helps build a deposit reliably. Premium Bonds suit savers who accept high variance for the chance of tax-free windfalls.
Opinion: Preserve the HTB ISA for likely purchases within two years, and choose Premium Bonds only when the bonus no longer matters. Premium Bonds work for savers who value access and chance over a guaranteed uplift. If certainty matters, a Cash ISA or keeping the HTB ISA is the safer path.
Practical modelling tips
Use a spreadsheet with columns: Balance, HTB bonus, prize-fund rate R, EV per year, and Years to match HTB. Compute Years for R = 0.5%, 1.0% and 2.0% to test sensitivity. Plot the probability of zero prizes over one and five years to show dry‑spell risk.
Check current figures on NS&I before you use the calculations. Small changes in R or p materially change expected returns and win probabilities.
Provider-specific transfer steps and timings to preserve
Different banks handle HTB transfers and claims differently. Follow the provider's HTB checklist and get written confirmation of processing times before you start.
Nationwide specific steps
Request the HTB transfer or closure form from Nationwide and ask for an estimated processing time in writing. Confirm whether Nationwide will send the bonus claim pack to your solicitor at completion. Follow the provider's exact form naming to avoid delays.
Halifax and Barclays specifics
Halifax usually needs the receiving ISA provider to complete an ISA transfer form. Request written confirmation of transfer timings from Halifax. Barclays asks for solicitor details early so it can prepare the HTB claim paperwork.
The key question to ask each provider is whether they will send HTB confirmation to your solicitor and how long that will take. Get the answer by email and keep the reply in your conveyancing file.
Keep paperwork copies in one safe folder for quick access.
Get the provider to email HTB confirmation to both you and your solicitor. Keep the email and transfer reference in your conveyancing file. This simple step makes the claim process smoother and reduces delays.
Common errors and warnings when moving HTB funds
Do not withdraw HTB funds and then expect the bonus to be claimed later. Direct withdrawal breaks the payment chain and usually voids the bonus. This action is the most common cause of the bonus being voided.
Transfer route to use
Do not use the receiving provider's savings withdrawal instructions. Use the official ISA transfer route instead. The receiving provider must request the transfer so the HTB wrapper stays intact.
Timing mistakes
Allow enough processing time before completion. Starting the transfer two weeks before completion risks paperwork delays. That risk may force a hurried withdrawal and forfeit the bonus.
Legal and tax notes to watch
The HTB bonus is part of the conveyancing completion monies and the solicitor includes it in the transfer to the seller. Check gov.uk for official HTB rules and requirements. See the Help to Buy ISA guidance on gov.uk.
National Savings & Investments publishes prize-fund rates and odds on nsandi.com/premium-bonds.
Quick visual preserve bonus vs move to bonds
Decision flow
Need HTB for purchase
Keep HTB ISA. Inform solicitor. No withdrawal.
No HTB needed
Consider transfer to Cash ISA or Premium Bonds after official transfer request.
Start transfers 6–8 weeks before completion. Internal transfers 5–10 working days. Inter-bank 10–30 working days.
Frequently asked questions
Can I move my Help to Buy ISA into Premium Bonds?
You cannot keep the bonus if you withdraw the funds and then buy Premium Bonds yourself. The HTB bonus is paid as part of a qualifying property completion when the solicitor claims it. Transfer using the official ISA transfer route if you need to move funds before completion.
How long does an HTB ISA transfer take?
Typical times are internal transfers five to ten working days and inter-bank transfers ten to thirty working days. Start transfers at least six to eight weeks ahead of completion to allow buffer time for paperwork and delays.
What exactly is the HTB bonus value for my account?
The bonus equals 25% of eligible saved amounts up to a £3,000 maximum. For example, saving £5,000 yields a £1,250 bonus, while £12,000 yields the full £3,000 for qualifying purchases.
How do I estimate Premium Bonds expected returns?
Estimate expected value as Balance times the prize-fund rate R. Run scenarios for R = 0.5%, 1.0% and 2.0% and compare cumulative EV over your horizon to the HTB one-off bonus.
What happens if the solicitor misses the HTB claim?
If the claim is missed, ask the solicitor to contact the ISA provider and HMRC or HM Treasury guidance promptly. Keep copies of provider confirmations and completion documents; missing paperwork can sometimes be resolved but may delay payment.
If I inherit Premium Bonds
NS&I pays Premium Bonds in probate or via a simple claims route for small estates. Payment timelines vary but NS&I provides guidance. NS&I payouts are often faster than some bank processes because NS&I holds the capital directly.
Final steps and documents to prepare
The HTB bonus is a guaranteed, substantial one-off uplift for a qualifying purchase and usually beats expected Premium Bonds returns for short and medium horizons. Preserve the HTB ISA when a first-time purchase is plausible within the next two years. Use official ISA transfer routes only if the bonus no longer matters.
Prepare these documents now: current HTB ISA statement, written confirmation from your ISA provider about HTB claim procedures, and solicitor contact details to share in writing. These three items reduce the chance of losing the bonus and give a clear audit trail.
The evidence points to a practical rule: preserve the HTB ISA when a first-time purchase is plausible within two years. Only move to Premium Bonds if the bonus is no longer relevant and the saver accepts prize volatility.
