Professional Liability Insurance (E&O): What It Covers, What It Costs, and Who Needs It

Professional liability insurance — also called errors and omissions (E&O) — protects service businesses from claims that their work, advice, or deliverables caused a client financial harm. If you sell expertise rather than physical goods, this policy is almost certainly necessary.

Why General Liability Is Not Enough for Service Businesses

Many service businesses believe their general liability policy covers everything. It doesn't. General liability covers physical harm — someone gets hurt, something gets damaged. It does not cover the scenario where your software project failed, your strategy advice backfired, or your accounting work contained an error that cost your client money.

The gap between general liability and professional liability is where most professional service claims fall. A marketing agency whose campaign produced zero results for a client is not facing a general liability claim — they are facing a professional liability claim. A software consultant whose code caused a production outage costing the client $1M in revenue is facing a professional liability claim.

A single professional liability claim — even an unfounded one that is ultimately dismissed — can cost $50,000–$200,000 in legal defense fees. Without E&O coverage, that comes out of your operating cash or personal assets.

Who Needs Professional Liability Insurance

Management Consultants

Strategy recommendations that result in client financial losses are the primary E&O exposure. Even when the advice was sound, if the client suffered losses while under your engagement, expect a claim.

IT and Software Professionals

Failed system implementations, data breaches resulting from code defects, and missed project deliverables are common claim categories. The cost of IT failures can be enormous.

Accountants and Bookkeepers

Tax filing errors, missed deadlines resulting in CRA penalties, and incorrect financial reporting create direct financial liability for the preparer.

Engineers and Architects

Design errors, specification mistakes, and project cost overruns attributed to professional guidance are the primary exposure. Most professional licensing bodies require E&O.

Marketing and Communications

Copyright infringement, defamation claims, and failed campaign performance claims are increasingly common as marketing accountability expectations rise.

Real Estate Professionals

Disclosure failures, transaction errors, and valuation disputes. Most provinces require E&O as a condition of real estate licensing.

What Professional Liability Covers (and What It Doesn't)

Covered

Professional negligence claims

Claims that you failed to perform your services with the care, skill, and judgment expected of a competent professional in your field.

Errors in work product

Mistakes in deliverables — reports, designs, code, filings — that cause a client financial loss, even if unintentional.

Omissions

Failures to include information, warnings, or recommendations that a reasonable professional would have provided and that a client relied upon.

Defense costs

Legal defense of a professional liability claim, even if ultimately unfounded. Defense costs alone can reach $50,000–$200,000 for complex matters.

Settlements and judgments

The policy pays settlements or court-awarded damages up to the policy limit.

Not Covered

Intentional fraud or criminal acts

Bodily injury or property damage (that's general liability)

Claims arising from work done before the policy retroactive date

Employment practices claims (requires separate EPLI coverage)

Claims known to you before the policy was placed

How Much Coverage Do You Need?

The standard starting point for most professional service businesses is $1M per occurrence and $2M aggregate. If you have enterprise clients with significant contract values, consider matching your policy limit to your largest contract value — if a client can lose $3M from your work, insure for $3M.

Many enterprise clients specify minimum insurance requirements in their master service agreements — often $1M–$5M in E&O coverage. Check your client contracts before buying; you may need more coverage than you initially assumed. The premium difference between $1M and $2M in coverage is often only $200–$500/year.

Frequently Asked Questions

Get the Right Professional Liability Coverage

ClearSide matches service businesses to commercial insurance partners who understand professional liability for your industry and jurisdiction.