Since May 1997, the FTSE 100 has fallen by 23% in real terms, says James Bartholomew on Telegraph.co.uk. And John Littlewood of the Centre for Policy Studies notes that in 1945-1951, 1964-1970 and 1974-1979, stocks lost 7.5%, 13%, and 11.4% respectively.
All the real growth in shares since the war has come under the Tories: 74.8% in 1951-1964 and 167% under Thatcher/Major; under Heath stocks fell. One problem has been a rise in regulation, but higher public spending also seems to play a part.
Britain, along with the other countries whose stockmarkets have done poorly since 1997, has seen an increase in the share of GDP taken up by government since then. Higher public spending implies higher borrowing and taxation, reducing corporate profitability, thus denting stock prices.
But “whatever the precise process”, it seems that Labour is bad for stocks.