I had 100% interest.. and well, exceeded the BIGINT limit, as set by MySQL.
Then, for fun, I decided to do this:
Also, since I think CK9 was asking:
BIGINT[(M)] [UNSIGNED] [ZEROFILL]
A large integer. The signed range is -9223372036854775808 to 9223372036854775807. The unsigned range is 0 to 18446744073709551615.
INT[(M)] [UNSIGNED] [ZEROFILL]
A normal-size integer. The signed range is -2147483648 to 2147483647. The unsigned range is 0 to 4294967295.
We used Signed BIGINTs for deposited and Signed INTs for on hand.