The overall deficit rose (or rarely fell) by many billions yesterday. While a great headline, it is total poppycock. The huge amounts injected by sponsors (see below) appear to have had zero or worse apparent funding impact. This has been economic illiteracy and capital destruction, with panic spread on a colossal scale. Good schemes have been closed to many members, which is really not just due to people living longer but rather because the assets and liabilities have not been properly compared. Using scalars to represent many future risks, which are not disclosed to stakeholders, is worse than unhelpful.
Over nearly 10 years, from Q2 2009 through Q4 2018, private sector employers paid DB contributions totalling £334b, of which special contributions accounted £136b, which were 68% of normal (from the ONS MQ5 series, currently temporarily suspended). Suppose that the annual discount rate (or expected return) was, on average, under-estimated by 1.5%. Indeed, just looking at how inflation tends to be estimated could easily lead to at least a differential of 1% pa. The 1.5% implies, say, a 30% difference in capital value. On that basis, I estimate that at least £100b of UK private sector employers' pension contributions were misallocated in UK during a very hard economic climate, which cannot have been an optimal outcome. This is my personal estimate but you can choose your own yield adjustment.