Last minute suggestions

the_learner wrote: »

- I open a help 2 buy ISA and the remaining part goes into a new cash ISA with good rate. Maybe using Nationwide would help since I guess I will use them for the mortgage?
- move existing HSBC ISA to Fidelity after April, which should not affect my ISA status on that amount of money

So just to clarify, there is £15k in Fidelity investments, £15k in HSBC cash ISA and a further £15k elsewhere that could be used to max out the 2016/17 ISA allowance? £45k total. So the two options you list above can both happen and you plan to do both, rather than choosing one between the other?

So far I was thinking:

- I open a help 2 buy ISA

Definitely do this. £1000 opening the ISA and £200 this month and £200 next month gets you £1400 in the ISA before the tax year is out. That offers a 25% bonus on top of the interest rate you earn and on top of the bonus you could earn for your 2017/18 deposits into the product.

The 25% bonus on £1400 is £280, which is almost 2% on the whole £15k you are going to put away, ignoring the actual returns you get in interest (or investment returns). If you're going to buy a qualifying property it is a no brainer to grab that extra bonus rather than miss it, so make sure you do this.

and the remaining part goes into a new cash ISA with good rate

As a HTB ISA is a type of cash ISA and you are only allowed one cash ISA containing current year money, the only way to do that is to select an ISA manager who is willing and able to split the cash ISA allowance across multiple products and report it all as one big ISA to HMRC. Nationwide are one such firm that allows 'split ISA' treatment and so you could do £1400 into their HTB and £13840 into their Flexclusive instant access ISA at 0.75%.

If you did Nationwide for the HTB you would not be able to do anyone else's cash ISA. You could put both the HTB and the 'ordinary' cash ISA with someone else but only if they support the 'split ISA' concept.

However, you'll find cash ISA interest rates (aside from HTB because it only takes very limited balances) are pretty low everywhere. If you are looking at only 0.75% inside an ISA and you are going to be taking the money out of the ISA wrapper anyway in a year or so to buy your house, your priority should not necessarily be using an ISA to avoid tax on the interest over the long long term, but finding the best net-of-tax interest rate you can in the shorter term.

For example if you are not a Nationwide customer and not already maxing out the Nationwide Flexclusive Regular Saver at £500pm for 5% on every penny deposited, do that. If you are not already using high rate current accounts at two or three or five percent and other regular savers at three or five percent, do those in preference to 0.75% in an ISA.

Maybe using Nationwide would help since I guess I will use them for the mortgage?

When you apply for the mortgage and are about to complete on your property, your solicitor will take your HTB closure account details from you and make a claim on the government for your bonus. Whether or not the HTB account was with Nationwide who happen to be your mortgage lender does not make a difference to getting the bonus, or the mortgage.

As an aside (not that it makes a difference to the above comments), it's probably too soon to guess that you will use Nationwide for the mortgage. I use them and they are fine. But you don't know what their rates and deals will be a year from now or what their competitor's rates and deals will be either ; a year out is way too far to conclude on who will have the best deal for you. Meanwhile of course there is no harm in using them for their other decent products.

- move existing HSBC ISA to Fidelity after April, which should not affect my ISA status on that amount of money

Moving an existing ISA to another new or existing ISA does not affect ISA status, that's right.

However, at that point you will have two thirds of your deposit in S&S ISAs and one third in cash (cash ISAs or other higher interest cash accounts). S&S ISAs have investment risk. There are not really any 'slow and steady' investment options which could get a return meaningfully higher than cash and could not also fall 20% over the course of a year. A mix of 50/50 shares and bonds could fall quite a lot further than that and it's not beyond the bounds of possibility for a 100% equities fund to lose half its value over a year.

So, if you plan to top up the Fidelity ISA to £30k from £15k, obviously you need to be comfortable with that £30k of funds only being worth £24k or £20k or less in a year's time and potentially needing to delay the purchase to allow for a number of months of savings to get back up to £30k (if you need the whole £30k towards the property).