By Scott Fulton, VP, Retail Analytics, Circana, and Scott Love, SVP, CPG Analytics, Circana
Many factors affect market share shifts, from price changes to competitor promotions. While retailers focus on such common causes, they may overlook the importance of assortment.
Indeed, what a retailer stocks — or no longer stocks, for that matter — plays an important role in driving gains and losses. Accordingly, assortment should be viewed as a measurable, controllable driver of share and gauged for its productivity in comparison to the market instead of just a retailer’s own plan.
Why Assortment Decisions Now Carry More Weight
As modern retailers understand all too well, the current operating environment is less forgiving of assortment miscalculations than in the past.
Three pressures contribute to challenges:
Consumer behavior has fragmented: Shoppers increasingly mix channels, brands, and pack sizes within a single week, making basket-by-basket decisions rather than loyal, repeatable ones.
Consumer confidence remains low: Financial pressure forces intentional behavior at the shelf. A shopper who bought a $6 party-size bag of chips last month may switch to a $4 regular-size bag this month to hold the weekly budget in line. The category did not shrink; the demand simply migrated to a different pack size, and the retailer that carries the wrong configuration loses the sale.
Supply chain volatility persists: Availability gaps and shifting product flows mean that an assortment planned on paper rarely matches the assortment shoppers actually encounter. Every out-of-stock in a key segment hands share to a competitor.
In this environment, assortment is a constant priority. The relentless cycle is exactly why retailers need a faster, more objective way to determine whether their choices are working.
Assortment as a Market Share Driver
Today, what a retailer carries or is planning to discontinue goes beyond a static plan. Executing your own strategy flawlessly means little if the market is moving faster than you are.
For example, one grocer may commit its carbonated soft drink space to 2-liter bottles and 12-packs. On its own terms, the plan looks solid and sales seem stable. Meanwhile, a competitor goes all in on 24-packs. As budget thresholds shift and value-seeking shoppers chase the lowest cost per ounce, demand tilts toward the larger pack. The first retailer can be executing perfectly and still bleed share, because it measured itself against its own plan rather than against where the market moved.
To see this clearly, a retailer needs to separate the controllable levers. Pricing, promotion, and assortment overlap and correlate, which makes it easy to credit or, alternately, blame the wrong one. Market share decomposition attributes share change to each specific driver, isolating internal execution from external market forces. When assortment is pulled apart from price and promotion, you can answer that difficult question with confidence.
How Assortment Decisions Shape Share Gains and Losses
Assortment influences market share through different mechanisms that demand attention.
Breadth and depth define category authority. Too little range in a growing segment signals that you are not the destination for it, and shoppers take their baskets elsewhere. Too much range creates clutter without adding sales.
Redundant SKUs cannibalize rather than grow. While it’s a common belief that a retailer’s assortment is highly differentiated, up to 80% of what sits on the shelf is the same across every competitor. Overlapping items compete for the same demand instead of capturing new demand.
Regional preferences expose localized leakage. A uniform national strategy hides share loss at the market level. What performs in one region might underperform in another; averaging the two conceals both the win and the loss. Local demand, then, should shape local assortment.
Turning Insight Into Action With Market Share Drivers
Circana’s Market Share Drivers solution provides retailers with crucial assortment insights that enable them to flag problems with merchandise mix. Armed with this evidence, merchants can isolate assortment, pricing, and promotion and gauge the true cause of share movement and determine if their assortment is more or less productive than the market.
From there, retailers can leverage other assortment analysis tools to delve deeper into actions they can take to optimize their share of the increasingly competitive market. For example, after learning that assortment is contributing to share loss, an organization can measure how each SKU contributes to sales and share and then determine which items should stay and which should give away.
With a clear look at shelf dynamics and consumer preferences, retailers can make a move to improve their scenario planning and capture white space opportunities.
This broad informed perspective ultimately aligns the organization. A unified scorecard and clear path forward ensure that every team — including executive leaders, merchants, and regional operators — works from a single version of the truth.
Assortment will keep moving, and so will the market. Winning retailers will measure their choices against the market in real time, act on evidence, and sync their teams around one clear picture of what is driving share.
