Why a renewal leak is the cheapest money in domaining
Nobody notices $12 a year. Everybody notices $12 a year times 300 names, because that is $3,600 a year of carrying cost that buys nothing. Sales are uncertain; renewals are a certainty. Trimming the renewal bill on the names you keep is the only portfolio decision with a guaranteed return.
Which files work
Any text with one domain per line. Registrar exports work too: the tool looks for columns named domain, renewal_cost (also renewal, annual_renewal, renewal_price) and registrar. Extra columns are ignored. Extensions outside the six in the partner table are listed separately rather than guessed.
What to do with the transfer list
Work registrar by registrar. Unlock the names, collect the auth codes, and bulk-transfer in one batch per destination — every partner in the table accepts a CSV of auth codes. Start at least three weeks before the earliest expiry in the batch.