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Measured by Spring Prompt

Gemini 4 Carbon: Why Pennywell customers don't use savings pots

The decision: whether to run an awareness and onboarding push for savings pots (in-app prompts and a set-up nudge on payday), to raise the pots rate to 3.85% AER, or both. The brief and the data →

Verdict
✓ Sound research
Research score
94 of 100
Analysis rating
1,076
Head to head, this task
won 6 of 8

Scorecard

Numbers 12 of 12 right

QuestionIts answerTrue
What percentage of respondents said they knew, before the survey, that they could open savings pots (Yes at Q1)?✓39.4%39.4%
Among respondents who were asked Q3, what percentage chose 'The interest rate is too low'?✓29.7%29.7%
As a percentage of all respondents, how many knew about pots and chose 'The interest rate is too low' at Q3?✓11.7%11.7%
Weighted to the age mix of all customers who have never opened a pot, what percentage of them would know about pots and choose 'The interest rate is too low' at Q3?✓8.8%8.8%
Weighted to the age mix of all 361,000 customers who have never opened a pot, about how many of them did not know they could open savings pots (No or Not sure at Q1)?✓239,702239,702
Among respondents who reported an amount held in savings elsewhere (excluding None, Don't know and Prefer not to say), what percentage hold less than £5,000?✓55.2%55.2%
What percentage of all respondents said they would be likely (fairly or very) to start saving in a pot if the rate rose to 3.85% AER?✓29.9%29.9%
Among respondents asked Q3, is the difference in the share choosing 'The interest rate is too low' between those aged 35-54 and those aged 55-74 statistically significant at the 95% level? (1 for yes, 0 for no)✓NoNo
What is the 95% margin of error, in percentage points, on the share of respondents asked Q3 who chose 'The interest rate is too low'?✓5.4 points5.39 points
How many of the open-text answers say the respondent did not know about savings pots or what they are, or want Pennywell to tell them about pots?✓126126
How many of the open-text answers from respondents aged 18-34 say they did not know about savings pots or what they are, or want Pennywell to tell them about pots?✓4646
What percentage of the customers invited completed the survey?✓6.03%6%

Traps in the data 8 of 8 handled

  • ✓Q3 was asked only of the 276 respondents who knew about pots. 'The interest rate is too low' leads there (30%), but that is 12% of all respondents (about 9% weighted), while 61% of all respondents did not know pots existed (No or Not sure).
  • ✓Customers aged 55 or over are 15% of non-users but 31% of respondents; they know about pots more and cite the rate more, so unweighted figures overstate awareness and the rate reason (weighted, awareness falls from 39% to 34%).
  • ✓The mean amount held elsewhere (£14,513) is pulled up by a few large balances; the median is in the £1,000 to less than £5,000 band and 55% of those reporting an amount hold less than £5,000. Many hold nothing elsewhere.
  • ✓30% say they would be likely to start saving in a pot at 3.85% (17% at the current 3.1%); these are stated intentions about a hypothetical rate.
  • ✓Respondents aged 75 or over (base 20) show 65% holding £20,000 or more elsewhere, against 13% overall.
  • ✓Only 700 of 11,600 invited customers completed (about 6%); those who respond to an email about savings may be more engaged with saving than those who do not.
  • ✓The chief financial officer believes customers don't use pots because the rate is uncompetitive.
  • ✓Among those asked Q3, the rate reason is 10 points higher for 55-74s (38%, base 120) than for 35-54s (27%, base 102), but the difference is not significant at 95%.

The analysis

Recommendation

Launch the awareness, UX, and payday onboarding push first at the current 3.1% AER—paired with placing pots prominently on the home screen, simplifying pot setup, and clearly stating 'instant 24/7 withdrawals in seconds'—and hold off on an across-the-board rate rise to 3.85% AER until incremental deposit economics are tested. Do not run a 75+ campaign. Nearly two-thirds of non-pot customers (~239,700 people) do not know pots exist, and a payday nudge at 3.1% lifts age-weighted intent higher than a 3.85% rate hike (35.1% vs 28.9%) without incurring immediate 75 bps margin dilution on existing pot balances. Once awareness and setup friction are fixed, evaluate a targeted promotional bonus rate or controlled rate test if treasury seeks larger external balance transfers from already-aware 35–74 savers.

What would change it

We would recommend raising the rate (or running both simultaneously) if: (1) finance modelling shows the existing pot back-book is small enough—or treasury's net interest margin above 3.85% is wide enough—that repricing existing balances is easily paid back by modest balance inflows from the 37.0% of already-aware non-users who say they would act at 3.85%; or (2) an initial A/B test of the payday nudge and home-screen placement produces high pot-opening rates with negligible funded balances (e.g. small short-term payday skims rather than retained deposits), demonstrating that capturing sticky external balances from 35–74 savers requires a competitive rate.

Findings

  1. Lack of awareness—not the 3.1% rate—is the primary bottleneck stopping customers from opening savings pots, especially among the younger majority of the customer base.

    High confidenceBase 700

    60.6% of unweighted respondents did not know (50.7%) or were unsure (9.9%) that pots existed before the survey (base n=700), rising to 78.4% among 18-34s (n=218). Weighted to the true age profile of the 361,000 non-pot customers (46% aged 18-34), 66.4%—roughly 239,700 customers—do not know they can open a pot. Awareness and basic explanation also dominated Q2 open-text responses (126 of 230 answers; 46 among 18-34s).

  2. Answer to CFO Question 1: 'Rate is too low' looks like the top barrier only because Q3 excluded unaware customers and the unweighted sample over-represents older savers; it does not justify leading with a rate rise to 3.85%.

    High confidenceBase 700

    While 29.7% (±5.4pp) chose 'The interest rate is too low' at Q3, Q3 was asked only of the 39.4% who already knew about pots (n=276). That equates to just 11.7% of all 700 respondents, and only 8.8% once weighted to the population age mix (as 55-74s are 28.6% of the sample vs 13% of the population). Moreover, the apparent difference in rate complaints between 35-54s (27.5%, n=102) and 55-74s (37.5%, n=120) is not statistically significant at the 95% level (z=1.59, p=0.11).

  3. An in-app payday nudge at the existing 3.1% AER outperforms raising the rate to 3.85% AER on stated adoption intent—without repricing existing pot balances.

    Medium confidenceBase 700

    Across all respondents (n=700), baseline intent at 3.1% is 17.4% (17.4% age-weighted). Adding a payday prompt at 3.1% lifts likely intent to 33.7% unweighted and 35.1% age-weighted—outperforming a standalone rate hike to 3.85%, which reaches 29.9% unweighted and 28.9% age-weighted. The payday prompt works directly on the previously unaware majority (42.5% likely among Q1='No', n=355; 47.8% among 'Not sure', n=69), whereas raising the rate to 3.85% converts only 24.2% of Q1='No' while doubling intent among those already aware (37.0% vs 18.1%, n=276).

  4. In-app discoverability, multi-step setup friction, and misconceptions about withdrawal speed are suppressing conversion at zero marginal cost to fix.

    High confidenceBase 276

    Among aware non-users (n=276), 22.5% cited setup uncertainty (10.9%) or not getting round to it (11.6%), and 7.6% worried about how fast they could withdraw money—even though pots are already instant-access. In Q2 (n=230), 29 respondents said pots are hidden under 'More' or hard to find on the home screen, 12 described abandoning or baulking at a fiddly multi-screen setup, and 10 wanted explicit guarantees of instant 24/7 transfers.

  5. Answer to CFO Question 2: The £14,513 average external savings figure cannot be extrapolated to estimate deposit inflows from a 3.85% rate rise; doing so would massively overstate likely balances.

    High confidenceBase 700

    First, £14,513 is the mean only among the 59.0% who hold savings elsewhere and gave a band (n=413); 35.7% hold £0 elsewhere (45.9% of 18-34s). Second, balances are heavily right-skewed and inflated by sample age bias: 55.2% of external savers hold under £5,000 (median £1,000–<£5,000), and weighting by population age cuts the share holding £20,000+ from 12.6% to 8.8%. Third, Q7 measures stated likelihood to 'start saving' (29.9%, +12.5pp over baseline), not full balance transfers, and Q2 shows external savers are anchored to incumbent banks/building societies (17 mentions) or expect 4%–5%+ best-buy rates to switch. Actual inflows must be estimated via controlled testing, not survey midpoints.

  6. Answer to Head of Marketing Question: Do not build a savings campaign around customers aged 75 or over; the evidence base is tiny, the segment is 2% of the population, and responsiveness is low.

    High confidenceBase 20

    The 75+ figures rest on just n=20 completes (and n=7 at Q3), giving ±21pp margins of error. Even in the full database, 75+ represents only 2% of non-pot customers (~7,220 people). Within the small sample, neither the payday nudge (25.0% likely) nor 3.85% rate (25.0% likely) meaningfully lifts intent above baseline (20.0%). If targeting older external balances later, 55-74s are 6.5x larger (13% of population, ~46,930 customers; n=200 in survey, 21.5% holding £20,000+) and more responsive to rate (33.5% at Q7), though back-book funding costs still apply.

Caveats

  • Unweighted sample skews heavily older than the target population (55-74 is 28.6% of respondents vs 13% of the 361,000 non-pot population; 18-34 is 31.1% vs 46%), inflating unweighted external savings balances, prior awareness, and rate sensitivity.
  • Low email completion rate (6.03%, 700 of 11,600 invited) creates non-response risk: more engaged or financially secure customers may be over-represented relative to dormant or cash-strapped current account holders.
  • Stated likelihood scales (Q5–Q7) systematically overstate real-world conversion, and Q6/Q7 were asked in a fixed order to all respondents without testing the combined effect of 'awareness/nudge + 3.85% rate' or actual pounds transferred.
  • The 75+ subgroup has only n=20 respondents (n=7 at Q3), making percentages in that column too noisy for standalone targeting decisions.
  • The survey covers only customers who have never opened a pot; it provides no data on existing pot balances, cannibalisation/repricing cost on existing pot holders if the rate rises by 75 bps, or Pennywell's treasury value of incremental deposits.

Next steps

  • decisionMove savings pots onto the main accounts/home screen (out from under 'More'), streamline setup into a single-screen flow, and add explicit 'instant 24/7 transfers back to your current account' copy.
  • experimentRun a randomised controlled A/B test of in-app awareness explainers and inbound-payment ('payday') set-aside nudges at 3.1% AER across non-pot customers with active current account inflows.
  • experimentModel back-book repricing cost and run a controlled rate/bonus pilot (e.g., a new-pot bonus to 3.85% AER or targeted offer to aware/older segments) rather than an immediate universal rate hike.
  • researchConduct quick usability testing (5–8 customers) on the revised pot creation and payday-nudge UI, alongside internal database analysis of inbound payment patterns by age band.
  • monitorTrack pot awareness, opening rates, and retained balances segmented by age band (18–34, 35–54, 55–74) post-launch.

Open-text themes it coded

Unaware of savings pots / want a clear explanation of what they are and how they work 126Higher or more competitive interest rate needed to make saving or switching worthwhile 45Pots are hidden or hard to find in the app navigation 29No spare money or financial constraints prevent saving regardless of features 23Habit, trust, or loyalty keeps savings with an existing bank or building society 17Not interested in saving or using savings pots under any circumstances 15Pot creation flow feels fiddly or has too many confusing steps 12Need reassurance that withdrawals back to the current account are instant and 24/7 10

The survey it planned

2 screening questions and 10 questions, as the model wrote them.

  1. S1

    Which age group are you in?

    One answer
    • Under 18
    • 18-34
    • 35-54
    • 55-74
    • 75 or over

    Continues if 18-34; 35-54; 55-74; 75 or over

  2. S2

    Before receiving this survey invitation, which of the following best described your awareness and use of Pennywell Savings Pots?

    One answer
    • I did not know Pennywell offered Savings Pots
    • I had heard of Pennywell Savings Pots, but didn't know how they worked
    • I knew about Pennywell Savings Pots, and have never opened one
    • I currently have, or have previously opened, a Pennywell Savings Pot
    • I no longer have an open Pennywell account

    Continues if I did not know Pennywell offered Savings Pots; I had heard of Pennywell Savings Pots, but didn't know how they worked; I knew about Pennywell Savings Pots, and have never opened one

  3. Q1

    Without checking the Pennywell app, roughly what annual interest rate (AER) do you think Pennywell Savings Pots currently pay?

    One answer
    • Less than 2.0% AER
    • 2.0% to 2.9% AER
    • 3.0% to 3.4% AER
    • 3.5% to 3.9% AER
    • 4.0% AER or more
    • I don't know

    Routing Shown only if S2 is: I had heard of Pennywell Savings Pots, but didn't know how they worked; I knew about Pennywell Savings Pots, and have never opened one

  4. Q2

    Why have you not opened a Pennywell Savings Pot so far? Select all that apply.

    Any that apply
    • I don't currently have spare money to put into savings
    • I earn a higher interest rate on my savings elsewhere
    • I thought the interest rate on Pennywell Savings Pots wasn't high enough
    • I didn't know what interest rate Pennywell Savings Pots paid
    • I wasn't sure where to find Savings Pots or how to set one up in the app
    • I haven't got around to setting one up
    • I prefer to keep my savings with a different bank or building society
    • I wasn't sure if I could withdraw my money instantly when needed
    • Another reason

    Routing Shown only if S2 is: I had heard of Pennywell Savings Pots, but didn't know how they worked; I knew about Pennywell Savings Pots, and have never opened one

  5. Q3

    Roughly how much money do you currently hold in instant- or easy-access savings accounts elsewhere, or set aside as spare cash in current accounts? (Please exclude fixed-term accounts where your money is locked away, investments, and pensions.)

    One answer
    • £0 - I don't currently hold any accessible savings
    • £1 to £499
    • £500 to £1,999
    • £2,000 to £4,999
    • £5,000 to £9,999
    • £10,000 to £24,999
    • £25,000 to £49,999
    • £50,000 or more
    • Prefer not to say
  6. Q4

    Roughly what annual interest rate (AER) do you currently earn on the account where you keep most of that accessible savings money?

    One answer
    • 0% (for example, in a current account paying no interest)
    • 0.1% to 1.9% AER
    • 2.0% to 2.9% AER
    • 3.0% to 3.4% AER
    • 3.5% to 3.9% AER
    • 4.0% AER or more
    • I don't know

    Routing Shown only if Q3 is: £1 to £499; £500 to £1,999; £2,000 to £4,999; £5,000 to £9,999; £10,000 to £24,999; £25,000 to £49,999; £50,000 or more

  7. Q5

    Pennywell Savings Pots are instant-access savings accounts inside the Pennywell app, currently paying 3.1% AER. Now that you know this, how likely are you to open a Pennywell Savings Pot in the next 3 months?

    Scale

    Scale 1-5: Very unlikely to Very likely

  8. Q6

    Suppose Pennywell kept the interest rate at 3.1% AER, and added in-app prompts and an optional set-up nudge on payday to help you move money into a pot. How likely would you be to open a Pennywell Savings Pot in the next 3 months?

    Scale

    Scale 1-5: Very unlikely to Very likely

  9. Q7

    Suppose instead that Pennywell raised the interest rate on Savings Pots to 3.85% AER. How likely would you be to open a Pennywell Savings Pot in the next 3 months?

    Scale

    Scale 1-5: Very unlikely to Very likely

  10. Q8

    At the current rate of 3.1% AER (with in-app prompts and an optional payday set-up nudge), roughly how much money in total would you realistically put into a Pennywell Savings Pot over the next 6 months?

    One answer
    • £0 - I would not put any money in at 3.1% AER
    • £1 to £499
    • £500 to £1,999
    • £2,000 to £4,999
    • £5,000 to £9,999
    • £10,000 to £24,999
    • £25,000 to £49,999
    • £50,000 or more
  11. Q9

    If the interest rate were raised to 3.85% AER (with in-app prompts and an optional payday set-up nudge), roughly how much money in total would you realistically put into a Pennywell Savings Pot over the next 6 months?

    One answer
    • £0 - I would not put any money in even at 3.85% AER
    • £1 to £499
    • £500 to £1,999
    • £2,000 to £4,999
    • £5,000 to £9,999
    • £10,000 to £24,999
    • £25,000 to £49,999
    • £50,000 or more
  12. Q10

    Which of the following best describes how money usually comes into your Pennywell current account?

    One answer
    • My main salary, wages, or pension is paid directly into Pennywell
    • I transfer money in regularly from another bank account for spending or bills
    • I top up my Pennywell account occasionally when I need it
    • I rarely or never add money to my Pennywell account
Sample plan

Sampling frame: The ~361,200 active Pennywell customers (86% of 420,000) flagged in the account database as never having opened a Savings Pot, stratified by database age into the four required bands (18-34, 35-54, 55-74, 75+). Precision vs. sample-size resolution: An unstratified random sample of 700 completes cannot meet the board's precision target for two reasons: (1) an app-only bank skews young, leaving very few completes aged 75+, and (2) even an equal split of 700 completes (n=175 per age band) yields a worst-case margin of error of +/-7.4 percentage points at 95% confidence (at p=50%). Achieving +/-5 percentage points at 95% confidence in every age band requires n=385 completes per band (1,540 completes total; slightly fewer in 75+ only if the total 75+ non-pot customer base is small enough for finite-population correction, e.g. n=323 if N=2,000). Because database email invitations carry negligible marginal cost, we recommend expanding the target to 1,540 completes (hard quotas of 385 per age band), inviting ~7,500-12,000 customers per band in waves assuming a 3%-5% email-to-complete conversion rate. If the ~700-complete cap is strictly enforced, apply stratified sampling with equal hard quotas of 175 completes per age band (n=700 total) and explicitly advise the board upfront that subgroup precision will be +/-7.4 pp at p=50% (reaching +/-5.1 pp for proportions near 15% or 85%). In either case, apply post-stratification weights matching the true age distribution of the 361,200 non-pot customers when calculating overall population estimates, while S2 filters out anyone who opened a pot after the database extract.