[nabla9]

Cash is universally considered the most liquid asset because it can most quickly and easily be converted into other assets.

If the amount of physical cash is huge however, say 1 billion euros, it can be less liquid than German government bonds. There is cost of moving, counting, securing it and significant delay for buying and selling. If you try to buy something for 1 billion EUR in cash, it might cost 100k EUR to do so and few days until you can buy anything.

But you are correct, there is probably a limit after wich banks start to convert some part of their assets to cash.

[arez]

the ECB also removed the 500€ bill, so the cost of storing cash went up, because you need greater storage, at least that was a theory that I heard

[nabla9]

Indeed. 500€ bill was known as "Bin Laden" because it was so hard to find one. It was estimated that 90% of the bills were held by drug dealers, money launderers and other criminals.

[princekolt]

They're gorgeous though. Because they're so low circulation, when you do get to see one they look brand-new. My father got one from a currency exchange this year and when he mentioned that I had to take a picture of it: https://imgur.com/a/aiaZmP2

Edit: I suppose since it was an exchange outside of Europe, they probably wanna put them in circulation before they lose legal tender status.

[nabla9]

They will maintain their legal tender status. ECB just stopped printing more and existing notes will be removed from circulation when they enter the banking system.