Core Insights - The UK Office for Budget Responsibility (OBR) mistakenly released a report revealing a significant increase in the fiscal buffer from £9.9 billion to £22 billion (approximately $29 billion) before the Chancellor's speech [1][3] - The report indicates that the fiscal space available for additional spending or tax cuts is the largest since March 2022, exceeding the median estimate of £15 billion [1] - The Chancellor's strategy includes raising £29.8 billion through new taxes on gambling and high-end real estate to expand the fiscal buffer [1] Group 1 - The OBR confirmed the authenticity of the leaked report and apologized for the premature release, stating an investigation has been initiated [3] - Following the report's release, the British pound fell 30 points against the dollar before slightly recovering, ending the day down 0.1% [1][3] - UK government bonds experienced volatility as traders processed the mixed information from the report, with the fiscal buffer being higher than expected but overall growth forecasts being downgraded due to lower productivity [3] Group 2 - Additional measures in the leaked document include imposing extra taxes on properties valued at £2 million or more and increasing tax rates on property and savings income by 2 percentage points [3] - Pension contributions exceeding £20,000 will no longer be exempt from National Insurance Contributions (NIC), and the employer NIC threshold will be frozen for three years starting in 2028-29 [3] - The government plans to introduce mileage-based charges for electric vehicles starting in 2028, while the freeze on fuel tax will be extended until September 2026 [3]