The Opening Story
He'd insured the building years earlier and the number had never been revisited. Construction costs rose. He didn't. Nobody re-ran the replacement value at any renewal, and every year he paid a slightly smaller premium than he should have without ever knowing it.
Then he had a loss. Not a total loss — a partial one, well under the limit on his policy.
The carrier applied a coinsurance penalty and reduced the payment by roughly $110,000.
He hadn't done anything wrong that he could see. He'd paid every premium on time. The penalty was in the policy the entire time, in a clause he'd never had a reason to read.
The Insight
Most commercial property policies include a coinsurance clause, typically at 80%, 90%, or 100%. It's an agreement: you insure the property to at least that percentage of its replacement value, and in exchange the carrier prices the policy accordingly.
If you're under that threshold when a loss happens, the carrier doesn't just cap you at your limit. It reduces the payment proportionally — even on a partial loss well inside your limit.
The mechanics, roughly: divide what you carried by what you should have carried, and the carrier pays that fraction of the loss. Insure to 60% of what you should have and a covered partial loss pays around 60 cents on the dollar, minus your deductible.
Two things make this dangerous:
It gets worse quietly. You don't have to do anything to fall out of compliance. Construction costs rise, your limit stays flat, and the gap opens on its own.
It rewards nobody for noticing. A lower limit means a lower premium. Nothing in your renewal flags the problem, and the penalty only appears at claim time.
The Protection Checkpoint
Find the coinsurance percentage on your commercial property declarations page.
Get a current replacement cost estimate. Not market value, not tax assessment — what it would cost to rebuild today, at today's material and labor prices.
Do the division. Your limit divided by that estimate. If you're under your coinsurance percentage, you have a gap right now.
Ask about an agreed value endorsement. On many policies it waives coinsurance entirely, and it's often inexpensive relative to what it removes.
Ask John
"How often should I update my building limit?"
Every renewal, and immediately after any buildout, expansion, or major equipment purchase. Through periods when construction costs move fast, a limit set three years ago is almost certainly short today.
The Bottom Line
Coinsurance is the only penalty I know of that a business owner pays for being responsible enough to buy insurance and unlucky enough not to reread it.
Pull your declarations page. Find the percentage. Do the math.
Not sure how to run the calculation on your own policy? Reply and I'll walk you through it.
John Crist
Prestizia Insurance
Author, The Prestizia Protection Playbook