UK Budget Faces Threat from Stock Market Volatility

The UK Chancellor's budget plan is under significant threat from stock market fluctuations, exacerbated by the outbreak of war in the Middle East, leading to a sharp decline in stock prices. According to Jin10, the Office for Budget Responsibility (OBR) has indicated that three-quarters of the anticipated £12 billion increase in government revenue for the 2030-31 fiscal year is attributed to previous stock market rebounds that boosted tax revenues. Despite presenting an overall optimistic forecast to Chancellor Reeves in Tuesday's spring budget update, the OBR warned that revenue growth driven by stock markets is highly susceptible to reversal if stock prices fall. Their forecast document estimates that a 10.3% drop in the stock market could result in a £10 billion reduction in tax revenue for the 2030-31 fiscal year. The Institute for Fiscal Studies (IFS) also highlighted this risk. The OBR assumes that UK stock markets in the first quarter are 8% higher than last November's forecast. IFS Director Helen Miller stated on Wednesday, "As we have seen in recent days, stock market gains can be fleeting. With capital gains tax accounting for a larger share of total tax revenue, we are more vulnerable to asset price fluctuations."