There is a very good reason why the banking industry does not use signed numbers.
For the computer illiterate, 2^14 is 16,384. When that value is exceeded, it wraps around to -16,384. Usually a negative balance on a credit card means they owe you money. 🙂
Although, I’m sure in real life, the banking industry would use a bit more than 14 bits to represent a number. Sad to say that the US National debt can’t even be represented in 32 bits.