Bank Storage Fees

There’s a 10% fee for storing treasure to leave to an heir.
How much for a reputable bank to simply store treasure and keep it safe?

Interesting question for a setting with magic. I could imagine in a high fantasy Renaissance-era you get major bank branches that are almost mini-dungeons - with wards, guards, even traps, ran by the major Houses. Using ACKs you could work out the manpower/materials/infrastructure costs. If the treasure is magic/dangerous/culturally significant I expect it’d cost more to store so it pays to establish a stronghold where you can stash the booty instead of relying on the bank’s reputation. I suppose I see banking as more of a moneylending/moneychanging racket than a safe haven for one’s ill-gotten items.

Yup. My players are currently buying chests for safe-keeping treasure, but I think they’d rather hire a banker with vaults and security to keep their treasure safe.
Seems like if they keep it safe to Will to an heir for 10%, they’d charge a similar fee for storing it for safe keeping?

Here are the rules I use for the Merchant’s Guild in Auran Empire:
Auction House: An auction house runs in the guildhouse every day except Ammonadras, where guild members can buy and sell common and precious merchandise.
Brokerage Services: The guild’s brokers can provide for purchase and sale of goods of up to 15,000gp value (10% commission); retainer of hirelings (10% commission on 3 month’s wages); and arrangement of transportation services, including coach cabs, messengers, and ship’s passage within the Auran Empire (5% commission).
Private Banking: The guild maintains a large vault and moneychanger. Banking is no charge if wealth is left for at least one month; otherwise there is a 10% fee on funds withdrawn. Loans at an interest rate of 3% per month can be obtained with collateral. Loans of over 5,000gp require a successful reaction roll. Money-changing is at a 10% fee.

Awesome! This helps.

If you want a great take on fantasy banking, you need to read Joe Abercrombie’s books. The banks secretly control everything - petty much just like in real life. It’s pretty depressing really. There’s also a very powerful bank in Game of Thrones which will probably be making some serious moves in the next book.