There is little doubt that European monarchs are very wealthy, but some are more than others.
Although it is not possible to know precisely how much they are worth, a lot of different estimations exists. The variations in numbers can be explained by the different criteria of calculations because sometimes it is hard to say what belongs to the monarch and what belongs to the state.
The richest monarch on the mainland continent is Prince Hans-Adams II of Liechtenstein. Indeed, his worth is estimated between £2.7 and £3 billion. The family owns the Liechtenstein Global Trust Bank Group, castles, extensive art collection and Prince Hans-Adams also holds an agricultural exploitation in Texas.
Grand Duke Henri of the Luxembourg has a fortune estimated at around £2.3 billion. The Grand Duke has a lot of personal investments including in gold and real estate.
Prince Albert II of Monaco comes in third with an estimated fortune of £768 million to £1.5 billion. This is not surprising as the Prince has stakes in the Monte Carlo Casino, an important art collection and an antique cars collection.
King Willem-Alexander of the Netherlands has an estimated fortune of £154 to £230 million. The Dutch Royal Family is one of the biggest shareholders of the Royal Dutch Shell Oil Company; they also have investments in other Dutch companies.
Some monarchs are much more secretive about their private fortune which makes the process of estimating their net worth even harder and less precise. That is the case of King Carl XVI Gustaf of Sweden (£54 million), Queen Margrethe II of Denmark (£30.7 million), King Harald V of Norway (£23 million) and King Felipe VI of Spain (£15.3 million).
Few records were to be found to report on King Philippe of Belgium‘s net worth. However, as of 2013, the monarchy claimed to only be worth around £10.9 million. According to the European Union Times, financial experts have estimated the Belgian monarchy could be worth up to £684 million.
Queen Elizabeth II‘s fortune is estimated at £345 to 422 million. She is very secretive about private holdings, hence the difficulty in estimating her fortune. It also depends on whether or not you are counting the Royal Collection and the Crown Estate (belongs to the monarch but the monarch has no controlling rights); the Crown Estate has a value of £11.5 billion, according to the Telegraph. This estimation is only taking into account her private wealth (i.e what she can sell, not what she owns as a sovereign). The Queen owns several castles (through The Duchy of Lancaster), as well as an impressive stamp collection started by her father, and horses. She also owns Balmoral Castle and Sandringham House.
These numbers are just estimations found by multiple sources, but they can obviously change depending on the method of calculation, what is taken into account and the year in which the estimates were made.