The OBR expects the two-point rise in tax on savings and property income to raise about £1bn a year, according to its Economic and Fiscal Outlook as reported by Tax Policy Associates.
The OBR puts the yield from the savings income rise at "£0.6 billion a year on average from 2028-29". It puts the yield from the property income rise at £0.4bn a year on average over the same period.
Those figures allow for savers moving money into ISAs and landlords moving property into companies. The OBR rates its costing of the property measure as 'High' uncertainty.
The official figures replace an unconfirmed Telegraph estimate that the measure would raise £4.3bn over five years. That averages about £0.86bn a year, so the Telegraph's figure is broadly in line with the OBR's. The Telegraph also had more coming from savers than from landlords, as the OBR does.
Tax Policy Associates says the measure is permanent, unlike the rise in the bank surcharge. The government says "84% of income tax payers will be unaffected". That claim has not been independently checked.