Free tool
Explain how the opening book became the closing book.
Enter four annual-premium figures from two Book snapshots. The bridge derives what changed on customers who stayed, so growth is separated from customer arrivals and departures instead of being reduced to one closing-minus-opening number.
Your book bridge
Opening bookAnnual in-force premium at the first snapshot
−
Lost customersOpening premium that departed with customers
+
Gained customersClosing premium that arrived with customers
±
Change on retained customersDerived remainder: rate, exposure, coverage, and mix together
=
Closing bookAnnual in-force premium at the second snapshot
Fill in all four figures to build the bridge.
The method
One equation, with the remainder named.
The roll-forward
opening − lost + gained + retained change = closing
The calculation forces the full premium movement to reconcile instead of leaving part of the change unexplained.
Lost and gained
customer absent at one endpoint
Classify customers by presence at the two snapshot dates. Policy rewrites and carrier remarkets remain with a customer who stayed.
Retained-book change
closing − opening + lost − gained
This derived remainder combines every premium change on customers present at both dates. More source detail is required to separate rate, exposure, coverage, and mix.
A consistent basis
annual premium at both endpoints
Do not mix written premium, annual in-force premium, and commission. Every input needs the same basis and scope.
What this cannot classify by itself
- Whether a gained customer is organic new business, a reactivation, or part of an acquired book.
- How much retained-book movement came from rate, exposure, coverage changes, or account mix.
- Why a customer left. A point-to-point Book export shows presence, not cancellation reason.
- Internal staff transfers at the agency level. Reassignment changes responsibility, not the agency's total book.
Related questions
Asked alongside this one.
How do you calculate movement in an insurance book of business?
Begin with annual in-force premium at the opening snapshot. Subtract the opening premium attached to customers who departed, add the closing premium attached to customers who arrived, and add or subtract the premium change on customers present at both dates. The result should equal closing annual in-force premium.
What is change on retained customers?
It is the difference between opening and closing premium for customers present at both snapshots. This combined figure can reflect rate, exposure, coverage, and mix. It should not be attributed entirely to employee sales activity or carrier pricing.
Does gained premium mean new business?
Not automatically. A customer absent at the opening snapshot and present at close is gained on a point-to-point book comparison, but the arrival could be organic new business, reactivation, or acquired business. Those classifications require additional evidence.
What Keelridge removes
The bridge is easy. Building the inputs is the work.
Keelridge compares recurring AMS Book snapshots, identifies which customers arrived, left, or stayed, and updates the roll-forward after the regular file is staged and confirmed. Owners get the current bridge and its history without reconstructing customer cohorts from separate reports each month.
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