Supplier invoices, payroll or contractor records, delivery and payment-processing statements, lease and utility bills, and the accounting export that maps each entry to a line. Sales receipts alone show revenue and nothing about the cost that produced it. Bank statements confirm movement but do not establish which segment absorbed the spending.
Build the mapping inside your bookkeeping
Set up segment tags in the bookkeeping file so future months produce the split automatically, then reconstruct earlier months from the underlying invoices. Keep the reconstruction notes; a reviewer can ask how a shared cost was divided. Funding evidence can be supplemented after an initial review, so an incomplete file is a task rather than a verdict. Lawful source and path of funds remain separate questions from segment costing.
Purchase orders, invoices, payments and bank records should tell one consistent story. Request tax returns, payroll records, licences and supplier contracts for several years. Money in the U.S. corporation’s account that could be wired home is not committed; an excavator that has been bought, a yard lease that has been signed for a term and a licence fee that has been paid are.
Identify actual payments, closing conditions and updated ownership records where relevant.