The Queen's income from her private Duchy of Lancaster estate has risen by almost a fifth to £16million.
The amount rose by 18%, increasing by £2.4million on last year, accounts for the year ending March 2015 showed.
The total capital value of the fund, a portfolio of land, property and assets held in trust for the Queen, has risen by almost 7% to £472.1million.
The estate is not subject to corporation tax as it is not a separate legal entity for tax purposes, but the Queen voluntarily pays income tax on revenue she receives from it.
The report stated: "The results for the year show a willingness to buy when the appropriate opportunities arise, and at the same time, to take advantage of the low interest rate environment."
Accounts showed the monarchy cost the taxpayer £35.7million for the second year running - the equivalent of 56p for each person in the country. The cost of travel rose by almost £1m during 2014/15 compared with the previous year, but royal household expenditure was the same.