£90k investment 5 years on?

[Amislytherin]

If you invested 90k in a savings account 5 years ago what would
you expect it to roughly look like now if you hadn’t taken any out of it?
it’s a long sad story I won’t go into here but my much older cousin received an inheritance of around that amount 5 years ago and seems he invested it in a fixed rate savings account and it’s now sitting at around £107000. He has dementia which we didn’t clock for a long time until he suddenly deteriorated last month and got the diagnosis. All paperwork is a mess and he dealt with all financial matters and his wife is simply lost trying to get her head around it. She says from what she can tell, the balance is no £107000, does this sound likely to you?
I earn very little and have a total of £900 to my name in savings and have never had enough to invest so have no clue whether this is likely or not! She’s worried he’s moved some money around and is trying to start
the process of taking financial control. thank you.

Good you aren't going to get a shock, savings and lending interest rates move in the same pattern, the difference between them being how banks and other lenders make money. Lending rates being higher than savings rates.

Aha. Thank you!

One follow up question if i may-

if She wants to move it, would it be wiser to move it to an ISA? Or
Another fixed rate savings account?

Well, that's a 2 part question, OP. ISA vs savings account is more about the TYPE of account, i.e. tax protected (ISA) or taxable. ISA's are great but you can only put £20k a year in.

The question of whether she wants to invest in interest-paying investments or something else is probably best discussed with a financial adviser, assuming she can get a decent one.

You wouldn’t be able to put it all in an ISA straight away - there is a £20k limit per tax year. She could move it over across several tax years though. Generally ISAs are great because they are tax efficient (no tax paid on growth), and would have the options of either cash (like a fixed rate savings) or stocks/shares.

https://www.thecalculatorsite.com/finance/calculators/compoundinterestcalculator.php

pop your figures in here, £90k for 5 years at 3.5 % fixed comes out at £107,173.19

tbh your relative did well 5 years ago to get 3.5 fixed, so well done him for making £17k interest

but now your relative should look at moving to another building society or bank paying 4.8% + as that would pay £5,259 annual interest. Some banks will pay interest separately into another account monthly- so you could obtain £438 per month. Obviously then the £107.173 would remain at that figure and not grow

I’d put £20k in an isa now before April 2024 and then after 6th April ( end of the tax year is still April 6th) put another £20k into an isa. It doesn’t have to be the same isa.

that leaves £67,173 to put in a high interest account, you could put £47,173 into a fixed rate savings bond or account until 2026 and leave £20k in an easy access savings account - there are a few paying over 4.5%, ready to put into an isa in 2025

your relative will need to be doing self assessment presently for tax on the interest over £1000