What it means
This cover exists because professional work can cause financial harm without anyone being hurt or anything being broken. An architect's miscalculation, an accountant's missed filing deadline or a consultant's flawed recommendation can cost a client real money, and the client may look to recover it.
It matters commercially for two reasons. Legal defence costs alone can run into six figures even when a claim ultimately fails, and many clients and regulators will not engage a supplier that cannot show a valid certificate of cover.
Policies are almost always written on a claims-made basis, meaning the policy that responds is the one in force when the claim is notified, not the one in force when the work was done. That is why firms buy run-off cover for several years after they stop trading, and why an unbroken chain of policies matters so much.
Premiums are usually set as a rate applied to fee income, adjusted for the type of work, the chosen limit of indemnity, the excess and the claims history. Higher-risk disciplines such as structural engineering or financial advice attract far higher rates than, say, graphic design.
Two limits deserve attention. The limit of indemnity may apply per claim or in the aggregate across the policy year, and the excess is the amount the business pays on every claim before the insurer contributes anything.
In practice
Real-world examples.
Example
An IT consultancy configures a client's stock system incorrectly, causing $210,000 of overselling and refunds. Its professional liability policy covers the settlement and the legal costs above the $20,000 excess, and the consultancy keeps the client relationship.
Example
A recruitment agency is sued after placing a candidate whose qualifications it failed to verify. The claim is eventually dismissed, but the insurer pays $64,000 of legal defence costs the agency could not have funded from its own cash flow.
Example
A small architectural practice wins a public sector framework only because it can evidence $5,000,000 of professional indemnity cover, double the level it previously carried. The extra premium of $6,800 is comfortably covered by the first project on the framework.
Formula
Calculation
Premium = (annual fee income / 1,000) x rate per $1,000 of income
Insurer payout = claim settlement + defence costs - excess, capped at the limit of indemnity
A consultancy has annual fee income of $3,200,000 and is quoted a rate of $4.50 per $1,000 of income for a $2,000,000 limit with a $25,000 excess.
Premium = ($3,200,000 / 1,000) x $4.50 = 3,200 x $4.50 = $14,400 a year
A client later claims that a flawed forecast caused a loss. The matter settles for $155,000 with $25,000 of legal defence costs, a total of $180,000.
Insurer payout = $180,000 - $25,000 excess = $155,000
Cost to the consultancy = $25,000
So a $14,400 annual premium turned a $180,000 event into a $25,000 one. Had the firm chosen a $50,000 excess to save roughly $2,000 of premium, its share of this single claim would have doubled.Case study
Seen in the real world.
Kestrel Vantage Advisory is a fictional consultancy invented for this illustrative case study. It carried a $1,000,000 limit chosen five years earlier when fee income was a quarter of its current level, and had never reviewed it.
A supply chain redesign project went wrong. The client claimed $1,400,000 in losses, and the case settled at $1,150,000 with $180,000 of legal costs. The insurer paid up to the $1,000,000 limit, leaving Kestrel to fund $330,000 from its own reserves plus its $25,000 excess.
The firm survived, but the episode consumed most of a year's profit. Kestrel now reviews its limit annually against the largest single contract value it holds, has moved to a policy where defence costs sit outside the limit, and maintains run-off cover on every completed engagement for six years.
Watch out
Common mistakes.
- Assuming general or public liability insurance covers professional errors, when those policies respond to injury and property damage rather than financial loss from advice.
- Letting cover lapse after a contract finishes, forgetting that claims-made policies only respond if a policy is live when the claim is notified.
- Setting the limit of indemnity once at start-up and never revisiting it as fee income, contract sizes and client expectations grow.
Questions
People also ask.
What does professional liability insurance not cover?
Deliberate wrongdoing, known circumstances not disclosed at renewal, contractual penalties the firm agreed to voluntarily, and bodily injury or property damage, which belong on other policies.
What is run-off cover?
It is a policy bought after a firm stops trading or ends a line of work, keeping cover alive for claims notified in later years, and it is typically maintained for six years.
Do sole traders and small firms really need it?
If clients rely on your advice or professional output, then yes, because a single claim can easily exceed a small firm's annual profit, and many client contracts and professional bodies require the cover anyway.
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