The Danger of One Big Deal in Your Pipeline
- No invented stats
- Written for UK readers
- 3 min read
- Published 22 October 2026
Every so often a deal turns up that's worth more than everything else in your pipeline put together. It is the best thing that has happened all year and it is quietly one of the most dangerous. Not because big deals are bad — because of what carrying one does to the person carrying it.
It breaks your forecast, mathematically
Forecasting works on aggregates. If you have thirty deals with a rough 30% close rate, you can say something sensible about the quarter, because the ones that fail and the ones that surprise you roughly cancel out. Apply the same 30% to a single deal and the number is fiction: you will not close 30% of it. You will close all of it or none of it, and the forecast will be wrong either way.
This is why weighted pipeline figures get so misleading when one deal dominates. A £300,000 opportunity at 50% shows as £150,000 of expected revenue, a figure that cannot occur. If you use a weighted pipeline value, it's worth pulling the outlier out and reporting it separately — "here's the weighted pipeline, and separately, here's the one deal that changes the year" — rather than letting it blend into an average it doesn't belong in.
It changes how you behave, which is worse
The arithmetic is the small problem. The behavioural effects are the ones that lose deals.
You stop prospecting. Not consciously. But when one opportunity could make the year, an hour spent on cold outreach feels like an hour stolen from it. Two months later the big deal slips a quarter and there's nothing behind it. This is a very common way a great opportunity turns into a terrible year.
You lose the ability to walk away. Once you need a deal, the buyer holds every card, and good procurement teams can smell it. You agree to the extra pilot, the custom work, the payment terms, the discount. Needing a deal is the most expensive negotiating position there is, which is worth remembering before you get anywhere near the procurement conversation.
You stop qualifying honestly. Awkward questions — who signs, what's the budget, what happens if this doesn't get approved — start feeling risky, because you don't want to hear a bad answer. So you don't ask, and you carry a deal for six months without knowing whether it was ever real.
What to do about it
Three rules, none of them complicated.
- Ring-fence your prospecting time and treat it as non-negotiable. Whatever your normal activity level is, it does not drop because of the big deal. This is the one that matters most.
- Qualify it harder than anything else in the pipeline, not softer. Big deals have more stakeholders, longer approval chains and more ways to die. The fact that you want it is not evidence that it's real.
- Forecast it separately and honestly. Tell your manager: here's my number without it, here's my number with it. That's a far more useful thing to give leadership than a blended figure, and it protects you when the date slips.
The counter-argument
There's a real case on the other side. Concentration is how small companies grow — a single anchor customer can fund a hire, prove a new sector, or turn a side product into a business. Spreading effort evenly across forty deals when one of them could change the trajectory of the company isn't prudence, it's a failure to recognise an opportunity. Some deals genuinely do deserve disproportionate attention.
The distinction isn't how much attention you give it. It's whether the rest of the machine keeps running. Give the big deal your best thinking, your best people and more of your week than anything else — but if the price of that is an empty top of funnel, you've bet the year on one buyer's internal politics. That's a bet you don't control, and the people who've made it once rarely make it twice.
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