Share of wallet
The share of a customer's total spending in a category that goes to one brand or company. It shows how much growth is left inside existing customers, and is common in banking, retail and B2B. Its limit is the ceiling: most buyers split their purchases across brands by habit, so share-of-wallet programmes tend to plateau, and growth usually needs more customers, not only more from each.
Where it's used
Used in loyalty programmes, key account management and retail CRM to size the growth inside the current base. Good when the data shows total category spend, not just spend with you.
How to calculate it
Share of wallet = Spend with the brand ÷ Total category spend
Worked example
Illustrative numbersA typical customer spends 400 a month on groceries, 120 of it in our chain. A loyalty plan aims to lift that share to 40% across 10,000 members.
Current share of wallet
120 at our store ÷ 400 total = 30%
Spend at 40% share
400 total × 40% = 160
Extra monthly revenue
(160 target - 120 now) × 10,000 members = 400,000
What it tells you
The upside looks large, but each point of share gets harder to win. Compare it with the revenue from adding new members before choosing where to spend.