"The cheapest safety deposit box, which is just 5cm high, 16cm wide and 49cm deep, costs £600-a-year-to rent. That compares to £465 for a box twice the size in Harrods, and £240 in Metro Bank – the UK’s largest supplier of safety deposit boxes with 150,000 boxes across 70 branches."
You probably do not qualify so I am going to use the info on Metro Bank.
- A box twice the size of a box for billionaires would be 10cm by 16 cm by 50cm = 8000 cubic cm. It costs 240 pounds a year, or about USD 300
- So it would hold 8litres = 8kg of water
- Assume, generously, that paper money is four times lighter than water (nowadays banknotes are not flat). That means the box would hold 2 kg of banknotes
- A USD100 note weighs 1 gram. So this would be 2000 such notes, or $200 000
So the yearly cost of holding cash in a Metro Bank safety deposit box is $300/$200 000, or 0.15%
This limits how negative interest rates can become.
If you do qualify, here is the website: https://www.internationalvaults.com/
It will cost you five times as much but they will pick you up in a Rolls Royce. And bigger boxes probably have lower prices per unit of volume.
