The Concentration Risk in One Large Property Account

Why this matters

A large property account is the fastest volume a small shop can add. It is also the only customer that can end your year with one email, and unlike a homeowner, it knows exactly how much of your calendar it occupies. Concentration does not hurt you while it is building. It hurts the first time the account wants something you would otherwise refuse, and by then the decision has already been made for you by your own schedule.

This is the operating version of the question, not the version a buyer asks when you sell. A buyer discounts you for concentration at a moment of your choosing. An account exploits it at a moment of theirs.

Two denominators, and they do not move together

Shops measure concentration one way, as a share of revenue or billed hours. That number is real and it is the wrong one to steer by.

Billed-hours share tells you what you lose if the account leaves. It is a survival number, and it matters for your runway.

Schedule share tells you what you can still say yes to. Measure it as the account's share of your prime-window hours, meaning the weekday hours a new customer actually wants to be seen in. It is a leverage number, and it is the one that moves first.

They diverge because property work clusters. A portfolio's work orders arrive on weekday mornings, cluster around turn dates, and expect same-week response. A residential customer wants the same hours. So an account at a modest share of your billed hours can already own most of the slots you would use to replace it, which means your ability to build a replacement pipeline dies well before your revenue looks concentrated.

That is the trap in one sentence: by the time the survival number looks alarming, the leverage number has been gone for two quarters.

The four thresholds, with their units

All measured per account, on the trailing quarter, not on a month and not on a running year.

The Boolean across these is OR, not AND. Any single trigger acts on its own. A shop sitting at 22 percent of billed hours with 47 percent of its prime window committed has crossed a threshold and must cap, even though the number it watches looks comfortable.

The step when the cap triggers is a cap, not a cut. Hold the account's work-order count at the prior quarter's level while you grow everything else. Cutting an account to fix concentration shrinks the denominator too, which is why it barely moves the ratio, as the arithmetic below shows.

Worked example: one shop, four quarters

A five-tech shop takes on a portfolio at the start of the year. Trailing-quarter figures, both measures:

Both measures rose in every quarter. The prime-window share was higher than the billed-hours share in all four quarters, and the gap between them widened each time, from 6 points in Q1 to 13, then 19, then 22. That widening is the whole story: the account was consuming schedule faster than it was consuming revenue, every single quarter.

Running the thresholds. Q1 and Q2 trigger nothing: 21 percent is under the 25 percent watch line and 34 percent is under the 40 percent leverage line. Q3 crosses both at once, at 33 and 52 percent. Q4 crosses the 35 percent danger line at 41 percent.

Note which one would have warned first if the shop had been watching only one number. Neither, in this case, because both crossed in the same quarter. But the prime-window measure was within 6 points of its trigger at Q2 while the billed-hours measure was still 4 points from its own lower trigger and 14 points from danger. The leading indicator was the widening gap, not either level.

What actually happened in Q3. The shop declined two multi-day residential jobs because the prime-window slots were committed. Neither customer came back. That is what a 52 percent prime-window share costs, and it does not appear on any financial statement.

The recovery arithmetic nobody runs before they need it

Take the Q4 position, 41 percent of billed hours, and set a target of getting back to 25 percent. There are exactly two routes, and both are worse than shops expect.

Grow the denominator, keep the account. Hold the account's hours flat and grow total billed hours until the account is 25 percent of the new total. Total billed hours have to reach 41 divided by 25, which is 1.64 times where they are now: a 64 percent increase in total volume, with no help from your largest customer, using a prime window that is 63 percent committed.

Shrink the account. Cut the account's hours and accept that your total falls with them. To land at 25 percent, the account's hours have to come down to roughly 20 percent of the original total, which is a cut of about half the account, and total billed hours land at about 79 percent of where they started. So you shed roughly a fifth of your volume to fix a ratio.

Neither number is a reason to panic. Both are a reason to act at the 25 percent watch line, where the same correction requires growth in the teens rather than in the sixties. The cost of waiting is not linear, and this is the arithmetic that shows why.

What the account extracts once it knows

Managers are not villains here. They are graded on cost per unit and vendor reliability, and a vendor who cannot walk is simply a vendor with a better price available. The asks arrive in a predictable order, and each one is individually reasonable:

• A rate hold at renewal, then a second one.
• Extended payment terms, framed as an accounting policy change rather than a negotiation.
• Small scope items absorbed as goodwill, which become expected.
• Priority response that quietly reprices your emergency coverage to zero.

The tell that you have crossed the leverage line is not the ask itself. It is your own reaction to it: when you find yourself calculating what you can afford to give rather than what the work is worth, the schedule already decided.

Hedges that work before you are concentrated

Quote deliberately outside the account, on a quota. Not "market more." A specific count of quotes per month to non-portfolio customers, held even in busy weeks, because busy weeks are exactly when the pipeline dies.

Protect a slice of the prime window. Reserve a fixed number of weekday prime-window hours per week that portfolio work orders cannot book. It costs utilization now and it is the only thing that keeps replacement possible later.

Shorten your terms exposure as share rises. The larger the account, the less of your cash should sit in its payment cycle at any moment. Progress billing on multi-day work and same-day invoicing do more here than any collections effort.

Rotate techs across accounts. A tech who serves one account exclusively builds a relationship the account can hire away, and takes the property knowledge with them.

Stagger the renewals, do not just chase new accounts

The hedge shops overlook entirely: when a single manager gives you several properties, do not let the agreements share one renewal date. Negotiate them onto a staggered calendar so no single conversation puts the whole relationship on the table at once.

This changes the shape of the risk without changing its size. At 41 percent concentration across four properties on one renewal date, you face one meeting that can remove 41 percent of your billed hours. The same 41 percent across four dates spread through the year means the largest single decision is a fraction of that, and a bad outcome on one gives you months to respond before the next.

It is also the easiest concession to win, because it costs the manager nothing and looks administrative. Ask at signing, when it is a scheduling detail. Asking later, after concentration has built, reveals exactly why you want it.

How to verify you got this right

Once a quarter, per account, compute both shares from your own scheduling data rather than from an invoice total:

• Account billed hours divided by total billed hours, trailing quarter.
• Account hours scheduled inside your prime window divided by total prime-window hours available, same quarter.
• The gap between the two, and whether it widened against the prior quarter.

Then check one thing that no ratio catches: count the quotes you issued to non-portfolio customers in the quarter, and how many you declined to issue for lack of capacity. A shop with acceptable ratios and zero declined quotes is fine. A shop with acceptable ratios that turned away work it wanted is already past the leverage line, and the ratios will confirm it one quarter late.

References

• See related: What a Buyer Reads Into Your Customer Concentration
• See related: How to Avoid Becoming the Cheapest Vendor on a Portfolio
• See related: The Signals a Property Account Is Going Bad
• See related: How to Price a Multi-Property Agreement