Share of Voice
A brand's share of all mentions on a topic compared to its competitors, expressed as a percentage.
What is Share of Voice?
Share of voice is a marketing metric that measures how much of the total market conversation or advertising presence a brand owns compared to its competitors, usually expressed as a percentage. It long predates AI search: in traditional advertising, share of voice originally meant the percentage of all ad spending in a category that one company accounted for, for example, if five car brands together spent $100 million on TV ads in a market and one spent $30 million of that, its share of voice would be 30%.
Why it matters
Historically, share of voice (SOV) was a media-planning metric defined as a brand's advertising expenditure as a percentage of total category advertising expenditure in a given market, channel, and time period (a concept formalized in advertising and media-planning practice well before digital or social measurement existed, and still used that way by measurement firms like Nielsen. A well-known finding from marketing research (popularized by the IPA and firms like Nielsen and Ehrenberg-Bass) is the 'SOV/SOM' relationship: brands whose share of voice exceeds their existing share of market tend to grow, with studies estimating roughly 0.5 percentage points of market-share gain for every 10 points a brand's share of voice exceeds its share of market ('excess share of voice'). The concept has since been extended well beyond paid media to cover a brand's share of mentions, impressions, or visibility across owned, earned, and social channels) and, more recently, within AI-generated answers.