It occurred to me today, that if I made a one-off pension contribution before the end of the tax year (Tue 5th Apr) then I would get the following (I have 2 children, am a basic rate tax payer, working 20hrs per week, with a gross income of around £27k pa - so I get WTC & CTC, although the WTC is all withdrawn due to income level and I am into the 39% withdrawal rates for CTC).
Contribution - say £80 net payment, tax relief added by HMRC = £100 in to pension fund.
Reduction in 10/11 income for tax credit purposes = £100, so an extra £39 (39% withdrawal rate) for 10/11 to be paid once my TC renewal is processed - so Jul 11 at the latest.
11/12 tax credits based on 10/11 income with an income disregard of £10k. 11/12 income withdrawal rate is 41%, so that £100 pension contribution also gives me an additional £41 tax credits in 11/12 to be spread over the year.
So - net payment £80
Net increase in tax credits - 10/11 £39 and 11/12 £41 = £80
No overall net cost and £100 payment into my pension plan.
Can anyone pick holes in this?
(am hoping not - because while a £100 one off payment into my pension is neither here nor there, a bigger payment is more significant but has the same overall cost - nothing, or to be totally accurate the interest lost on the amount put in now, as the additional tax credits will come back 4-weekly over the next year.
As I see it, you could do this up to a gross contribution of £10k, so £8k net payment, and if all other things remained equal for 11/12 v 10/11 then you stay within the £10k income disregard. For a margin of error I would error on the side of caution and maybe do a £8k gross contribution.)