Customer concentration: how a buyer reads it

Customer concentration is how much of your revenue depends on your largest customers. In a subscription business it’s usually measured as a share of MRR: what percentage comes from the top customer, from the top ten, and how many customers each account for more than a set share on their own. A buyer looks at it because a concentrated business can lose a large part of its revenue in one cancellation, and because a big customer often has more say over price and terms than the business would like.

This guide covers how concentration is measured in a SaaS business, why the trend matters as much as the level, and the questions a buyer asks about large accounts.

Measure it as a share of MRR

For a subscription business, measure concentration as a share of MRR at a point in time. MRR is what renews, and it isn’t distorted by one-time fees or by the month an annual invoice happened to be billed. Many general definitions use annual revenue or bookings instead, which suits other kinds of business better.

The measures a buyer typically asks for:

• Top customer share: the largest customer’s MRR divided by total MRR.
• Top 10 share: the ten largest customers’ MRR divided by total MRR. Some analysts also ask for the top 20.
• Customers above a threshold: how many customers individually account for more than 5% or 10% of MRR.
• The trend: all of the above, month by month, over the last 12 to 24 months.

Here’s an example. These are illustrative numbers, not data from a real company.

	Jan 2026	Jun 2026
Total MRR	$80,000	$70,000
Largest customer	$9,600	$9,600
Top 10 customers	$30,400	$30,400
Top customer share	12.0%	13.7%
Top 10 share	38.0%	43.4%
Customers above 10% of MRR	1	1

Why the direction matters as much as the level

In the example, no large customer changed what it pays. The top-10 share still rose by more than five points, because smaller customers churned and total MRR fell from $80,000 to $70,000. To a buyer, rising concentration usually means one of two things:

• the long tail is shrinking, which is a retention question, or
• growth is coming from a few large accounts, which is a dependency question.

Either one leads to follow-up questions. That’s why a single reading of concentration is less useful than a monthly series. Read it next to net revenue retention, since high NRR driven by a few expanding accounts and rising concentration are often the same story.

Concentration inside a plan

Overall concentration can look fine while one plan depends on a handful of customers. For example, an enterprise plan might have six customers and 15% of total MRR. None of them stands out in the top-10 share, but losing one would cut that plan’s MRR by about a sixth. Looking at concentration by plan, along with each plan’s share of MRR, shows where the dependency really sits.

The same goes for billing cadence. If most of your largest customers are on annual contracts, the risk is concentrated on their renewal dates.

What a buyer asks about large customers

Once the largest customers are identified, expect questions like:

• What’s the contract term, and when does each one renew?
• Have they downgraded, asked for discounts, or paid late?
• How long have they been customers, and how did their spend change over that time? (This is where cohort analysis helps.)
• Is the relationship tied to one person on either side?
• Could they build the product themselves or move to a competitor easily?

None of these questions are unusual. What makes them hard is answering them for the first time during a live process.

What a founder can do about it in a year

Concentration mostly changes slowly. The levers that move the measure:

• Grow the base under the large customers. New and expanding smaller customers lower every share.
• Reduce churn in the long tail. In the example, all of the increase came from smaller customers leaving.
• Lengthen or stagger large contracts, so that several renewals don’t fall in the same quarter.

Some things only change how the numbers look, such as grouping related entities differently or leaving a customer out. A buyer’s analyst will rebuild the measure from the customer list, so presentation changes don’t survive diligence.

What counts as high customer concentration?

There’s no universal threshold. Buyers, lenders and investors each set their own, and the level they accept depends on the customer type, contract terms and the rest of the business. What you can control is knowing your own numbers, how they’ve moved, and the story behind your largest accounts before someone asks.

How Bright Vault shows this

Bright Vault calculates concentration from your Stripe history, month by month:

• Top-1, top-10 and top-20 shares of MRR
• The number of customers above 5% and 10% of MRR
• A top-customers table
• Plan and billing-cadence mix over time

Every view can be filtered by plan. Reports are private to your team.

For where concentration fits among a buyer’s other requests, see the SaaS due diligence checklist.

FAQ

What’s the difference between customer concentration and revenue concentration?

They’re often used interchangeably. Customer concentration usually means share by customer. Revenue concentration can also mean share by product, channel or geography. In SaaS diligence, the per-customer view is the one asked for first.

Should I measure concentration on MRR or on revenue?

On MRR for the recurring business, because that’s what renews. Recognized revenue is useful too, especially if large customers also pay for services. If you show both, label which is which.

Does a parent company with several subscriptions count as one customer?

A buyer will usually group related accounts under one parent when measuring concentration. If several Stripe customers belong to the same organization, expect them to be combined, and check how they change your numbers before the buyer does.