Most IFRS 16 problems don't start in the accounting model. They start in the lease contract.
Somewhere between page 12 and page 37 of a property lease is usually a clause that quietly changes the numbers in your spreadsheet. If you miss it, the lease liability, ROU asset and expense profile can all be wrong before you even start.
Here are five clauses that regularly surprise finance teams.
1. The "Perfectly Harmless" CPI Rent Review
This one usually reads something like: "Rent will increase annually in line with CPI."
Simple enough, right?
Except under IFRS 16 you don't forecast inflation when calculating the lease liability. You use the current index level at commencement, and only remeasure the lease liability when the index or rate used to determine the payment changes.
Which means if someone has enthusiastically added 3% CPI growth for the next 10 years into the lease model, the liability is probably overstated.
Think of it this way: IFRS 16 prefers facts over forecasts. Future inflation belongs in the news, not in your opening lease liability.
2. The Renewal Option Everyone "Knows" Will Be Used
Lease agreements love a good extension clause: "The tenant may extend the lease for a further five years."
Legally optional. Economically, often inevitable.
Under IFRS 16, if management is reasonably certain to exercise the extension option and they have the right to do so, that extension becomes part of the lease term.
So your 5-year office lease quietly becomes a 10-year accounting lease, which means:
- bigger lease liability
- larger ROU asset
- longer depreciation period
Auditors love asking about this one. "Why did you assume the extension wouldn't be exercised?" If the answer is "because the spreadsheet said five years", that conversation may take a while.
And importantly, this assessment is not static. If circumstances change, the lease term must be reassessed. For example, if the company commits to significant leasehold improvements, that may make exercising the option reasonably certain, triggering a remeasurement of the lease liability.
3. Rent-Free Periods That Aren't Actually Free
Property leases often include incentives like:
- three months rent free
- landlord fit-out contributions
- cash incentives
They sound like a nice gift from the landlord. In accounting terms, they're really just part of the lease economics.
Lease incentives reduce the right-of-use asset. A £200k landlord fit-out contribution means the ROU asset is £200k lower than the lease liability. Just keep in mind that any expenses you have incurred for the fit-out will be recognised separately, as an asset for leasehold improvements.
The rent-free period isn't a bonus. It's just the landlord helping pay for the asset you're recognising.
4. Residual Value Guarantees Hiding in Equipment Leases
Vehicle and equipment leases sometimes include wording like: "The lessee guarantees the residual value of the asset at the end of the lease."
Which sounds harmless until you realise it might mean: "If the asset is worth less than expected, you make up the difference."
Under IFRS 16, amounts expected to be payable by the lessee under residual value guarantees are included in the lease liability calculation.
This clause shows up often in:
- vehicle fleets
- heavy equipment
- specialised machinery
And it's one of the most commonly missed data points during lease implementations. Mostly because it's usually written in very polite legal language.
5. "Variable" Payments That Are Actually Fixed
Some leases proudly announce: "Payments are variable." Which sounds reassuring. Except sometimes the payment is only variable in theory.
Example: "A minimum monthly payment applies, plus an additional charge based on usage."
Even if part of the payment varies, the minimum amount is unavoidable and must be included in the lease liability. These are called in-substance fixed payments, and they must be included in the lease liability.
In other words, just because the contract calls something a variable doesn't mean IFRS 16 agrees.
The Real Lesson
IFRS 16 calculations look complicated. But most mistakes happen before the spreadsheet opens. They happen when:
- renewal options are ignored
- incentives aren't captured
- CPI clauses are misinterpreted
- residual guarantees are missed
- variable payments aren't analysed properly
The standard itself is usually the easy part. The tricky part is reading the lease agreement carefully enough to understand what the payments actually are.
Which is why, in lease accounting, the most powerful tool isn't Excel. It's reading the contract properly.
Why Rubli Helps With These Clauses
If you've ever tried to model leases in spreadsheets, you'll know the real difficulty isn't the formula. It's keeping track of everything the contract says.
Clauses like CPI rent reviews, renewal options, incentives and residual value guarantees all change how the lease is measured. Miss one detail and the numbers can quietly drift away from the contract.
Rubli is designed specifically to deal with these kinds of situations.
Instead of forcing finance teams to build complex models, Rubli captures the actual economic terms of the lease and applies the correct accounting automatically.
That means:
- CPI and index-linked payments trigger automatic remeasurements when the index or rate changes
- Renewal and termination options can be incorporated into the lease term assessment
- Lease incentives and rent-free periods are correctly reflected in the ROU asset calculation
- Residual value guarantees and payment structures are captured in the lease liability
- Every change is tracked through a complete audit trail
The result is a lease register that reflects what the contract actually says, without fragile spreadsheets or manual recalculations.
Because under IFRS 16, the numbers don't start with accounting. They start with the details buried in the lease agreement.
