RE: Sell to re buy2 Oct 2020 20:23
If you personally pay £800 into your SIPP then HMRC add £200 (providing your "net relevant earnings" support the contribution) taking the gross contribution to £1,000 - it appears to be a 25% addition but in reality is 20% of the gross contribution.
"Net relevant earnings" are basically gross pay from employment, or adjusted taxable self employed profits, and the max you can pay in each year is £40k pa GROSS (ie £32k personally and £8k tax relief added). Income from sources such as interest, dividends, property etc are not classed as "net relevant earnings".
Regardless of net relevant earnings (or none at all), a taxapayer can pay up to £2,880pa into a pension and HMRC will top up by a further £720 (making £3,600 into the pension regardless of eearnings status)