The bills of sale, the buyer's payment records, the deposit into her account, tax reporting of the disposition, and the transfer records moving the proceeds to the enterprise.
An unbroken chain from asset to enterprise
Source-of-funds review follows money rather than accepting a description of it. Selling haying and feed equipment produces a natural documentary trail if it is preserved: dated bills of sale identifying each machine, the buyers' payments, and the deposits arriving. Tax filings reporting the sale corroborate both the amount and its lawfulness. From there the chain continues through any currency conversion and cross-border transfer into the enterprise's account and out again to its suppliers. The common weakness is a period where funds sat in a personal account mixed with other money, so a short written explanation supported by statements should accompany any point where the trail is not self-evident. Keeping the records in date order, with a covering schedule, saves considerable time later.
Hypothetical example: A Canadian furniture-restoration owner uses proceeds from selling workshop equipment to finance a United States refinishing studio. The first review should create a dated table linking the sale agreement, buyer payment, bank deposit, tax record, currency conversion, and business expenditure. Contemporaneous bank and closing records settle each link. If personal and business money was mixed, identify the statements that explain the movement rather than relying on a narrative prepared later. This sequence reveals missing proof while replacement records may still be available.