Big coins have been introduced, after many players complained about the maximum amount of stackable items (2,147,483,647). One big coin is worth exactly 1000 coins. It can used as normal coins in shops, or even the Grand Exchange. The maximum amount of cash you can have with big coins is exactly 2,147,483,647,000gp.Note that you can have big coins and normal coins at once, which means you can have up to 2,149,631,130,647 gp at once. In theory, if someone were to keep 2,149,631,130,647 gp in their bank and 2,149,631,130,647 gp in their inventory, they could have up to 4,299,262,261,294 gp.