Inheritance Tax receipts rose by £2.7bn or 35% between April and August.
The rise of £700mn reflects the increase in the average value of estates on death and a higher death rate due to the pandemic.
Sharp increases in house prices and the value of shares prices means that the value of estates were higher than they were in previous periods.
In addition, the pandemic has led to a higher rate of deaths of the over 60s who have significant levels of wealth in excess of the £325,000 nil rate band.
Despite increase in government receipts, there is speculation the government may introduce reforms following changes to national insurance and dividend tax.