What are bordereaux in reinsurance?

Bordereaux are the schedules that turn a treaty into rows. Premium, claims, commission. Monthly or quarterly. The cedent sends them. The reinsurer has to post them against the wording that was actually signed. A covering email that restates a total is not a bordereau. A chat summary of a workbook is not a bordereau. The file is the object.

The word is French. The singular is bordereau. Operators still say the bords. Layouts differ by cedent and by quarter. Column names drift. Totals in the email disagree with the sheet. That is the job, not an inconvenience around the job.

How it works

Premium bordereaux list what was written and what was ceded in the period: policy reference, insured, class, territory, premium, share, dates. Claims bordereaux list paid, outstanding, event date, report date, and a policy reference that should exist on the premium file. Commission files apply the formula in the wording, not the rate in last quarter's header.

The order is fixed. Extract the treaty terms with spans. Map the inbound cells. Validate row by row. Exception what does not fit. Then book. Guessed totals do not close the quarter. They delay the dispute.

Reconciliation is not a vibe. It is questions with cited answers. Does this policy fall inside class, territory, and period? Does the share or the attachment match the treaty? Did the cedent restate prior quarters, and is there a bridge? If event date is empty on a claims row, attachment to period cannot be shown. That is a gap, not a booking.

Year of account follows the wording, not the day the spreadsheet was emailed. Premium written in December and reported in January is either this treaty or next, according to the contract. If the inbound file mixes years without a column you can cite, stop. Do not split rows by instinct.

Worked example

A property quota share includes construction. The inbound premium sheet for the first quarter of 2026 lists ACME Construction Ltd, acme.example, policy ACME-PROP-2026, gross premium USD 180,000, period 1 January 2026 to 31 December 2026. The wording cites a 30 percent share and excludes a named flood zone. The sheet has a column the mapper used last quarter as class. This quarter that column holds a branch code. Class sits two columns to the right.

The ACME row is inside class and period. The share should cede USD 54,000 of premium, not 30 percent of a covering-email total that used a subtotal row. If the location on the schedule sits in the excluded zone, the row is an exception with a span into the wording and a cell into the sheet. It is not a rounding item.

What goes wrong

Template maps follow last quarter's headers. When a column inserts, the policy reference silently becomes something else. PDF scans of printouts look complete and cannot be summed. Mixed currencies without a rate as-at produce a total nobody can unwind. Claims files use report date as if it were event date.

Do not flatten premium, claims, and commission into one tab because the subject line said bordereaux. They are three jobs. Keep them separate in the pack even when the cedent combined them.

Related reading

The glossary term is bordereaux. The long operations note is the bordereaux automation guide. Treaty structure around those files lives on treaty reinsurance.