Wells Fargo statements print an ending daily balance only on the last transaction of each day, leaving the column blank on other rows. That half-empty column is a free test for a parser: group rows by date, add each day's amounts to a running total, and compare with the printed balance.

A mismatch tells you which day lost or mangled a row, not just that the month is off.

I'm on the ZeraBooks team, where we convert a lot of these. The usual advice is "check that the month ties to the ending balance," which is right but coarse: a month that's off by 425.00 could be off anywhere in 30 days. The daily balance narrows it to one day, and it's sitting in the statement already.

The layout

A Wells Fargo business checking statement typically prints one transaction table with columns for date, check number, description, deposits or credits, withdrawals or debits, and ending daily balance. Credits and debits are separate unsigned columns, and the balance column is filled only on a day's last row.…