Picture the fire already out. The adjuster has been, the property claim is moving, contractors are quoting the rebuild. Now count the months: permits, construction, inspections, restocking, and then — the part owners underestimate — the slow climb while customers who found alternatives drift back. Through all of it, rent or mortgage payments continue, key staff need paying or they're gone, and revenue is zero.
That gap is what business interruption insurance exists to fill, and it's the difference between businesses that survive a major loss and businesses that technically got paid for one. Insurers' claims experience is blunt on this point: underinsured interruption closes more recovered-property businesses than the property damage itself.
What the coverage actually pays
Business interruption replaces the net income you would have earned, and covers the expenses that continue whether or not you're open — rent, utilities, loan payments, insurance itself, and the payroll you choose to maintain. Most forms also fund extra expenses that shorten the shutdown: temporary premises, rented equipment, expedited shipping on replacement machinery.
The trigger matters: standard coverage requires physical damage from an insured peril, at your premises. It's the companion to your property policy, not a revenue guarantee against any bad month — a distinction the pandemic made painfully public, and one worth understanding before you rely on the coverage.
The indemnity period: where sizing goes wrong
The indemnity period is how long the coverage pays, and it's the single most common sizing mistake. Twelve months sounds generous until you sequence a real recovery: two months of demolition and permits, six of construction, one of fit-out and inspections — and you've reopened at month nine to customers who spent nine months shopping elsewhere. Revenue rarely snaps back on opening day; it recovers on a slope.
That's why 18 to 24 months is the honest indemnity period for many businesses, and why extended indemnity wording — which keeps paying after reopening until revenue actually recovers — earns its premium. Run the timeline for your own operation pessimistically: municipal permitting speed, contractor availability, equipment lead times. Then pick the period.
Getting the numbers right
Interruption limits are built from your financials — gross profit, continuing expenses, payroll strategy — and they age quickly. A business that grew 30% since its last renewal is 30% underinsured on interruption without anyone making a mistake. Make the coverage part of your annual review: current revenue, current margins, current rent.
Two extensions deserve deliberate decisions rather than defaults. Contingent business interruption responds when a key supplier's or customer's loss shuts you down — increasingly relevant in thin supply chains. Utility and service interruption covers outages that stop you without touching your building. Neither is automatic; both are cheap relative to the exposures they close.
At claim time: the measurement game
Interruption claims are measured, not estimated — the insurer reconstructs what you would have earned from your records. Clean books, monthly statements, and pre-loss budgets make that reconstruction fast and favourable; shoebox records make it slow and conservative. It's one more return on bookkeeping nobody mentions.
Expect the process to run alongside the property claim and lean on your broker through it — measuring lost profit involves judgment calls where an advocate on your file genuinely changes outcomes.
A worked example: the bakery fire, month by month
Make it concrete with a composite: a neighbourhood bakery doing $50,000 a month in revenue takes a serious kitchen fire in March. Months one and two disappear into demolition, permits, and insurance process — revenue zero, while rent ($4,500), loan payments, insurance, and the two bakers the owner can't afford to lose ($9,000) continue. Months three through seven are rebuild and equipment lead times; month eight is inspections, restocking, and reopening. Real recovery then takes until roughly month fourteen, as regulars who found other Saturday routines drift back.
The interruption claim, properly covered: roughly $200,000 of lost profit and continuing expenses through the closure, plus the extended-indemnity months while revenue climbed home — call it $260,000 all-in, against a property claim of similar size. Now run it with the common mistakes: a 12-month indemnity period stops paying at month twelve, two months before recovery; a limit based on three-year-old revenue underpays every month; and no extra-expense coverage means the pop-up stall at the farmers' market that kept the brand alive was funded from the owner's line of credit.
One business, one fire, and a five-figure swing in outcome decided entirely by how the coverage was structured years earlier. That's why this is the policy section worth an annual hour — the fire is hypothetical until it isn't, but the wording is real today.
Extra expense: the coverage that shortens the shutdown
Inside most interruption forms sits the provision that changes recovery behaviour: extra expense coverage. It pays costs beyond normal operations that reduce the interruption — renting temporary premises, expediting equipment freight, outsourcing production to a competitor, overtime for the reopening push. The logic is aligned incentives: every dollar of extra expense that shortens the shutdown saves the insurer multiple dollars of lost-income claim, so the coverage exists to fund your hustle.
Use it deliberately. The businesses that recover fastest treat the adjuster as a partner in a reopening project: here's the temporary space we can take Monday, here's the expedited-shipping quote on the replacement oven, here's the overtime plan — approve and we cut the closure by six weeks. Adjusters approve reasonable versions of that math routinely, because it's their math too. Businesses that don't know the coverage exists simply wait, at full lost-income cost to everyone.
Planning tip: sketch your own 'plan B' now, in peacetime. Where would you operate from for three months? What's the one machine whose lead time would gate everything? Whose kitchen, warehouse, or office could you borrow? Fifteen minutes of answers, written down, turns extra-expense coverage from a clause into a plan — and turns your worst month into a logistics problem instead of an existential one.
Beyond your own walls: contingent and supply-chain triggers
Standard interruption coverage triggers on damage at your premises — but modern businesses can be shut down by fires they never see. The bakery's flour supplier burns; the anchor tenant that drives your plaza's foot traffic closes for six months; the sole fabricator of your product's key component floods. Contingent business interruption extensions respond to exactly these: losses flowing from physical damage at a supplier's, customer's, or attraction property rather than your own. In an era of thin, single-source supply chains, it's a coverage conversation that has moved from exotic to ordinary.
The underwriting requires homework you should do anyway: naming your dependencies. Which single supplier, if offline for a quarter, would materially cut your revenue? Which customer concentration would hurt if their operations stopped? Where inputs are genuinely single-sourced, the extension gets priced and bought deliberately; where alternatives exist, the homework doubles as continuity planning. Either way, you finish knowing where your revenue actually lives — knowledge most businesses only acquire during the outage itself.
Utility interruption belongs in the same conversation: coverage for outages of power, water, or telecom that stop your operations without touching your building, usually with a waiting period measured in hours. For refrigeration-dependent, production, and connectivity-critical businesses, it closes the gap between 'the grid failed' and 'nothing on my premises was damaged, so nothing was covered' — a gap owners tend to discover in exactly the wrong week.
Common wording traps worth asking about by name
Three wording details separate interruption policies that perform from ones that disappoint, and each is a one-question conversation with your broker. Gross earnings versus profits forms: the older gross-earnings structure stops paying at resumption of operations, while profits forms pay until revenue actually recovers (up to the indemnity period) — for businesses whose customers return slowly, the difference is months of coverage. Ask which form you hold.
Waiting periods and deductibles: interruption coverage often carries a time deductible — 24 to 72 hours commonly — which matters enormously for short-sharp outages like power failures or closures by civil authority. Know yours, and weigh it against the outage patterns your business actually faces. And civil authority extensions: when access to your undamaged premises is blocked by authorities because of damage nearby (the fire three doors down, the watermain collapse on your block), civil authority coverage responds — for a limited number of weeks, within a defined radius. Confirm the extension exists and note its limits; urban businesses use this more often than any other interruption extension.
None of these are exotic negotiations — they're checkbox differences between markets, visible only when someone compares wordings instead of premiums. That comparison is the working definition of broking, and interruption coverage is where it pays most.
The bottom line
Buildings are replaceable on a schedule; customer relationships and cash flow are not. Business interruption is the coverage that funds the space between them. Size the indemnity period for the recovery you'd actually face, revisit the numbers yearly, and treat extended indemnity as the default rather than the upgrade.
If you can't say today what your interruption limit and indemnity period are, that's the review to book — talk to an advisor or fold it into a full program quote. It's a one-hour conversation about the worst year your business might ever have.