I worked at a small community bank for a number of years. The software we used actually did track the decimal out a few places beyond what you see (used mostly for interest calculations). However, the larger infrastructure isn't built (yet) to handle those sub-cent values between banks. Also, smaller institutions have a tendency to have a lot of those transactions printed on paper and stored as per federal regulations (paperless is always almost here!) so there is an actual cost to tracking those little tiny transactions, not to mention that small unnoticeable transactions are the floater transactions that fraudsters use to test the viability of raiding an account. When it comes to cash, it's time to move the opposite direction, nothing less than deci-dollars is worth striking up in coin, drop pennies, nickels and quarters.