Share of Search, Market Share and the Number That Can't Flatter You

If your marketing dashboard is up and to the right and you still have a nagging feeling about it, that feeling is worth listening to. Almost every number on a dashboard can improve while the business quietly loses ground, because almost none of them look outside the business. Market share in search is the number that resolves it, because it's measured against the competitors who are taking the work you're not.

Last year I sat with a legal client, a sharp firm that had done the sensible thing and read the numbers they had. Traffic was up. Enquiries were up. Then I showed them a chart they hadn't seen before: about half a percent of tens of thousands of monthly searches in their market, and the smallest firm on the list. They saw the implication before I'd finished explaining it, and that one chart shaped the next twelve months more than any audit finding did.

This is the written version of the conversation Nic and I have with every client: what market share in search is, how it differs from share of search, how we measure it, and how to turn it into a revenue number a board will act on.

Why can every marketing metric improve while the business shrinks?

Because nearly all of them compare you to your own past. CTR compares this month's clicks to this month's impressions. Sessions compare this quarter to last.

If your market grows by 20% and you grow by 10%, every internal chart goes up and to the right and you have lost ground. Nobody puts "we grew slower than the category" on slide one.

CPA is the sneaky one. Narrow targeting to the people who were going to buy anyway and cost per lead falls while the dashboard applauds. In plain English, you've got cheaper at winning a smaller slice of the market.

Market share is different because the denominator isn't you. It's the total demand in your market, and someone else is counting it too.

What is market share in search, and how is it different from share of search?

Share of search is the recognised industry term, from Les Binet's work at adam&eveDDB, presented through the IPA in 2020. It's searches for your brand divided by searches for every brand in your category. Binet showed it tracks market share in cars, energy and mobile handsets, and in cars it moved up to a year ahead. In plain English, when more people type your name into Google relative to your competitors' names, sales tend to follow. Google Trends gives it to you for nothing.

Share of voice started life in advertising as your share of category ad spend. SEO tools borrowed the phrase for how visible you are across a set of keywords. When we report that Convoy ATX reached 32% share of voice, that's the second meaning.

Market share in search is what we build our work around. It's your share of the clicks available across the whole keyword universe of a market, not just brand terms, weighted by where you rank, split between organic and paid, and measured against named competitors. Share of search tells you how many people want you. Market share in search tells you how much of the actual demand you capture when people go looking for what you sell.

If you're a consumer brand with real branded search, track Binet's metric. If you're a B2B or professional services firm where nobody searches your name until after they've found you, share of search tells you almost nothing. That's when you need the market share version.

How do we measure market share in search?

Four steps, no data scientist required.

Define the keyword universe

Every market gets its own list of the queries a buyer uses, organic and paid together. For a legal client that might be 400 to 800 queries across five or six service lines; for a B2B software client in three countries it's a separate universe per country. The universe is the market. If it's wrong, every number downstream is wrong.

Weight positions by a click-through curve

Ranking third isn't a third of ranking first. We apply a CTR curve to each position, so position one on a query with 1,000 monthly searches is credited with roughly 250 to 300 clicks and position eight gets perhaps 20. Paid uses the ad account's own click data. The output is an estimated click count per domain per query, which means we're counting the traffic the market hands out, not rankings.

Name the competitors

Every domain that takes clicks goes on the list, including the ones nobody calls competitors: comparison sites, directories, national brands, government pages. Leaving them out makes the picture look better than it is. If a comparison site takes 30% of your market's clicks, that's 30% you can't have until you know why.

Produce one share number per market per month

Client clicks divided by total clicks in the universe, repeated monthly, plotted against each named competitor. That's the whole output. I get excited about this stuff, as you can probably tell, but the point is that a board member can read it in ten seconds.

You don't need perfect data to start. Volumes are estimates, CTR curves are averages, and AI Overviews are moving clicks around. To be honest, the absolute number could be a point or two out. It doesn't matter, because you're measuring the trend and the gap to competitors the same way every month. The one rule is never to change the universe mid-year.

What did half a percent tell a legal client?

Back to the client from the top of this piece. A legal and property firm, tens of thousands of searches a month, holding about half a percent of them.

Three things came out of that chart. The largest local competitor had around ten percent, so the ceiling for a local firm was twenty times where the client sat. The two smallest firms on the list were taking double the client's share. And 70% of the clicks went to national brands, comparison sites and government pages, so no local firm had claimed the market at all.

I said at the time that, given the website had grown up piece by piece as the firm grew, half a percent wasn't bad. I also said, looking at the graph, that it was winnable. Both were true.

What changed was the conversation. Before the chart, the brief was "more enquiries". After it, the brief was "get from half a percent to five", and every fix, from three service pages carrying a charity page's heading to the site structure we rebuilt, was judged by whether it moved that number.

How do you turn a share number into a revenue number?

This is Nic's rule more than mine: if we can put revenue figures around the audit, and what that could do for the business, the work gets funded. A share number with a pound sign next to it is a decision.

The maths is four multiplications. Share points gained, times total monthly clicks in the market, times your conversion rate from click to enquiry, times the value of an enquiry.

Here's an illustrative example, not the legal client's actual figures. Say the market is 40,000 clicks a month. One share point is 400 clicks. If 3% of visitors enquire, that's 12 enquiries. If one in four becomes a matter worth £2,500 in fees, one share point is worth £7,500 a month, or £90,000 a year. Going from half a percent to five percent is four and a half points, which is £405,000 a year from a market you're already in.

Once you've done that sum, "should we invest in search" stops being a marketing question. It's a question about whether £405,000 a year is worth the cost of going and getting it, and most boards answer that quickly. Share points are also a far better base for a forecast than rankings. We cover that in our piece on SEO forecasting.

The useful property of this sum is that it works in both directions. If your share has fallen two points while your CTR improved, you can put a pound figure on the gap your dashboard couldn't show you. It's not a comfortable number, but it's a better starting point for a budget conversation than a feeling, and lost share is fixable.

What does market share change at board level and with investors?

Boards don't care about impressions, and they're right not to. When the plan on the table is a redesign of the website, the first question an investor asks is where the money's coming from. An investor invests in the return, and the hope that there's a return for them.

Three things happen when a share chart replaces a traffic chart. The marketing budget gets defended on the same terms as a sales hire. Competitors get named, which turns "digital" from a cost line into a fight the board understands. And when share falls, the chart says so, which is uncomfortable for a month and useful for a year.

It also keeps us honest as an agency. If the share number is flat for two quarters, that's on us, and the client can see it. It's the standard we hold ourselves to on Wigwam, where the outcome was £1.4m of revenue in 2025 rather than a slide of sessions.

What discipline does it force on SEO and paid?

One keyword universe, argued over by both channels. In my head that's the whole point of integrated search.

When SEO and paid share one universe and one share number, they start talking to each other. Organic says, no, no, I'm okay, we do well over here, go and spend money elsewhere. Paid says, the likelihood of us ranking for this is very low, so I'll do the heavy lifting here. The budget goes where market share is cheapest to buy.

Without a shared number, the pattern we see most often when we inherit an account is paid bidding on terms the site already ranks first for, and SEO writing content for queries paid has already proven don't convert. Neither team is doing anything unreasonable; they just can't see each other. The share number doesn't move. The over-reliance on Google Ads will eventually come back to haunt some companies, and this is why.

For B2B, where one enquiry can be worth five figures, this matters more than anywhere. See our guide to SEO for B2B, and for the attribution side, our marketing attribution guide.

Questions we get asked

What is search market share?

Your share of the clicks across every query buyers use in your market, organic and paid, weighted by position, against named competitors. Unlike traffic or leads, it can only go up if someone else's goes down.

How is share of search different from share of voice?

Share of search, as Les Binet defined it, is your share of branded searches in your category. Share of voice was originally share of ad spend and is now used by SEO tools for visibility across a keyword set. Neither counts clicks against named competitors across the full market.

How do you calculate market share in search?

Build the keyword universe for your market, estimate clicks per domain by applying a CTR curve to each ranking position and adding paid click data, then divide your clicks by the total, every month. The formula is simple; the work is in the universe.

Can a small company measure market share?

Yes, and small companies get more from it, because half a percent of a big market is a growth plan rather than a number to apologise for. You need a keyword tool, a spreadsheet and a consistent monthly routine.

What tools do you use for market share dashboards?

Semrush or Ahrefs for volumes and rankings, Search Console and the ad accounts for actual clicks, a sheet or BigQuery for the CTR weighting, and Looker Studio on top. Build the logic before the dashboard, or you end up with a pretty chart of a number that doesn't mean much.

Where we fit

We run search and CRM programmes for B2B and professional services companies, and market share is where every engagement starts. It's stage one of the CLEAR Method, the first output of our market opportunity analysis, and the frame for the competitive analysis that names who is taking the clicks you're not. Convoy ATX reached 32% share of voice this way.

If you'd like to know what share of your market you hold, and what a point is worth, get in touch and we'll tell you what we'd need to work it out.