I can do the maturity value in 1993.
I reckon it would have got the General Extension Rate (GER) after 1993 (such as it was). I haven't kept details of the GER because I never needed to use it (I rolled stuff over manually on maturity, then in about 2012 NS&I started doing rollovers automatically by default)
A bit of a long shot, but does anyone have a record of the GER paid on fixed rate savings certificates from 1993.
I'm just starting out on this long road of research, but thought I'd post here first in case anyone does have the records, before I get stuck into it.
A bit of Googling and the best I can come up with (apart from some very old paperwork of mine from that period which is quite haphazard) at present is:
https://nsandi-corporate.com/news-research/news/changes-old-savings-certificates
and https://www.nsandi.com/files/published_files/asset/pdf/welsh-interest-rates.pdf which says:
NS&I wrote:As of 11 November 2013 War Savings Certificates (1916-1920) and Issues 2-43 of Fixed Interest Savings Certificates earn the General Extension Rate (variable) 0.09% pa tax-free/AER (variable) from 1 April 2009.
I have a leaflet dated April 1993: "Twenty Questions about Matured Certificates" and Q2 What do mature Certificates earn now?
NS&I wrote:Most mature fixed-interest and most mature Yearly Plan Certificates are now earning the variable General Extension Rate - at present 3.75% pa earned for every completed period of three months. If you would like more details about the variable General Extension Rate and a list of changes in this rate since it was introduced inJune 1982 write to the address at the end of this leaflet and ask for our General Extension Rate leaflet.
I have talked to NS&I but (a) this is so far from memory that it takes a lot of digging and (b) the people that might know are quite hard to get hold of.
Many thanks